Small snails in a big place: a radiation in the semi-arid rangelands in northern Australia...

Small snails in a big place: a radiation in the semi-aridrangelands in northern Australia (Eupulmonata,Camaenidae, Nanotrachia gen. nov.)

FRANK KÖHLER* and FRANCESCO CRISCIONE

Australian Museum, 6 College Street, Sydney, NSW 2010, Australia

Received 22 February 2013; revised 29 April 2013; accepted for publication 2 May 2013

Continuing the revision of the Camaenidae in the Australian Monsoon Tropics, we employed comparative analysesof morphological features (with a focus on shell and penial anatomy) and genetic markers (with a focus onmitochondrial COI and 16S sequences) to address the systematic relationships of land snails from the VictoriaRiver District, Northern Territory, and adjacent East Kimberley (Western Australia). These analyses revealed thatthe species under study represented the previously undescribed genus Nanotrachia. This genus differs from allother camaenid genera known from north-western Australia most conspicuously by its small, flat, and ribbed shell.Six species are identified as members of the new genus, four of them new species (Nanotrachia costulatasp. nov., Nanotrachia carinata sp. nov., Nanotrachia coronata sp. nov., Nanotrachia levis sp. nov.). Twofurther species have already been described previously but assigned to different genera. These species, Ordtrachiaintermedia (as the type species of Nanotrachia) and Mouldingia orientalis, are here transferred to Nanotrachia.Like other camaenids from the Australian Monsoon Tropics, species of Nanotrachia are characterized by essentiallyallopatric distributions, regional endemism, and a patchy distribution across their range.

© 2013 The Linnean Society of London, Zoological Journal of the Linnean Society, 2013, 169, 103–123.doi: 10.1111/zoj.12051

ADDITIONAL KEYWORDS: Australian Monsoon Tropics – Helicoidea – morphology – mtDNA –phylogenetics – taxonomy.

INTRODUCTION

The fauna of the semi-arid rangelands in northernAustralia is impacted by anthropogenic threatsrelating to grazing, the introduction of weeds andferal animals, changed fire regimes, and climatechange. These impacts together were shown tocause changes in the species compositions of ants(Hoffmann, 2000) and extinctions in mammals(Woinarski et al., 2007, 2011); however, because of thevastness and inaccessibility of the region, its inverte-brate fauna in particular remains poorly documented.These persisting knowledge gaps render the monitor-ing of faunal changes in most groups difficult toimpossible, and our understanding of current faunaltrends incomplete.

Land snails are particularly susceptible to thealteration of habitats, and increased intensity andfrequency of fires, and have therefore been identifiedas a potential bioindicator group for monitoring envi-ronmental health and for biodiversity conservationin semi-arid Australia (Braby et al., 2012). In termsof species numbers and abundances the Camaenidaeis the predominant land snail group within thisregion. In addition, these invertebrates are character-ized by moderate to high levels of narrow-range ende-mism and beta-diversity (Hugall & Stanisic, 2011).However, as holds true for most other invertebratetaxa, our current knowledge of the fauna is based onpatchy collections undertaken mostly in easily acces-sible areas along roads and highways, whereas vastregions have essentially remained unsurveyed untiltoday.

As part of the Australian Monsoon Tropics (AMT),the Victoria River District (VRD) is located about

*Corresponding author.E-mail: [email protected]

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Zoological Journal of the Linnean Society, 2013, 169, 103–123. With 7 figures

© 2013 The Linnean Society of London, Zoological Journal of the Linnean Society, 2013, 169, 103–123 103

500 km south of Darwin in the north-west of theNorthern Territory. Characterized by tropical savan-nah, the VRD forms a transition zone in which thefauna and flora typical of the higher rainfall forestsgradually gives way to that of the arid and semi-aridwoodlands, shrublands, and grasslands typical ofthe centre of the continent. More than 30 camaenidspecies in some 13 genera have so far been describedfrom the VRD, and in the immediately adjacent areasof the East Kimberley (EK) in Western Australiaby 20th century workers (Iredale, 1939; Solem, 1984,1985a). However, the camaenids of the VRD havenever been treated as comprehensively as their coun-terparts in the Western Australian Kimberley, whichhave been surveyed twice, in the late 1980s (Solem,1991) and between 2008 and 2010 (Gibson & Köhler,2012). The camaenids of the semi-arid VRD and EKare commonly found to show a coherent pattern ofassociation with exposed limestone outcrops (Solem,1984, 1985a), and because of this many species havea patchy distribution across their range. Previousstudies also showed that the patterns of distributionare predominantly allopatric, and that a maximum ofthree different species may co-occur syntopically, butoften fewer than this (Cameron, 1992).

Between 2007 and 2009, the first ever helicopter-based field survey of land snails was conducted inthe VRD and EK in order to achieve a more completedocumentation of the land snail fauna throughout theregion. By documenting the current diversity anddistribution of the land snail, this survey will providethe foundation for the monitoring and assessment ofthe above-mentioned impacts. As a direct result of thesurvey, our ongoing work has resulted in the discov-ery of several new species and new genera throughoutthe region. In a pilot study, Criscione, Law & Köhler(2012) revised the taxonomy of one genus, ExiligadaIredale, 1939, which included the description of thir-teen new species. Exiligada species were largelyfound to be endemic to areas of outcropping limestonewith a diameter of between 20 and 150 km. Althoughthe ranges of up to seven species overlapped, nevermore than three species were found to co-occur at anygiven locality. This finding underpins the patchinessof species distributions and the mutual ecologicalexclusion of species, which probably relates to thelimitations to realise different ecological niches in aharsh environment. In another study that has beenbased on the collections undertaken during the VRDsurvey, we have revised the taxonomy of the genusMesodontrachia Solem, 1985. In this case we foundthat six not closely related species were lumpedtogether into one polyphyletic assemblage, which infact represented five different genera with nearlyidentical shells. The morphological conservatism inthe shell is thought to have resulted from strong

selection towards a certain phenotype in species thatinhabit a similar, and again comparatively harsh,environment (F. Criscione & F. Köhler, 2013b). Here,we continue our revisionary work of the Camaenidaein the VRD by studying samples of supposedly newspecies of a yet undescribed genus. The species exam-ined here are readily distinguishable from Exiligadaand ‘Mesodontrachia s.l.’ in terms of their smallershell size, flatter shape, and marked shell sculpture.Just as a similar shell in the two previous generamight relate to the use of similar ecological niches,the starkly different shell of the species treatedhere might reflect a different pathway in adapting toa life under certain environmental constraints. Byemploying comparative analyses of morphological andmolecular characters, we address species limits andinfer phylogenetic relationships as a provision to cor-rectly delineate and describe monophyletic taxa.

MATERIAL AND METHODSMATERIAL

This study is based on newly collected, ethanol-preserved samples and dry shells deposited in themalacological collections of the Australian Museum(AM), the Museum and Art Galleries of the NorthernTerritory (NTM), and the Western AustralianMuseum (WAM) (Table 1). Collection sites spanned anarea of about 20 000 km2 throughout the VictoriaRiver District in the Northern Territory and the EastKimberley in Western Australia (Fig. 1). Samplesfrom the same collection site are referred to as lots.Holotypes are dissected, ethanol-preserved speci-mens, the shells of which were cracked to permitaccess to soft tissues. References to specimen size arerelative to other congeneric species.

MOLECULAR STUDIES

DNA was extracted from small pieces of foot musclefrom up to four specimens per lot with the QIAGENDNA extraction kit for animal tissue, following themanufacturer’s standard procedure. Fragments ofthe mitochondrial 16S rRNA (16S) and of the cyto-chrome c oxidase subunit I (COI) genes were ampli-fied by PCR using the primer pairs 16Scs1 (Chiba,1999) and 16Sbd1 (Sutcharit, Asami & Panha, 2007),and L1490 and H2198 (Folmer et al., 1994), respec-tively. Reactions were performed with annealing stepsof 90 s at 55 °C for 16S and 60 s at 50 °C for COI.Both strands of PCR fragments were purified andcycle sequenced by use of the PCR primers. Electro-pherograms were corrected for misreads and forwardand reverse strands were merged into one sequencefile using CODONCODE ALIGNER 3.6.1 (CodonCode

104 F. KÖHLER AND F. CRISCIONE

© 2013 The Linnean Society of London, Zoological Journal of the Linnean Society, 2013, 169, 103–123

Tab

le1.

Mu

seu

mre

gist

rati

onn

um

bers

,lo

cali

tyda

ta,

and

Gen

Ban

kac

cess

ion

nu

mbe

rsof

the

sam

ples

ofN

an

otra

chia

gen

.nov

.st

udi

ed

Taxo

n

Mu

seu

mre

gist

rati

onn

um

ber

Sta

tus

Loc

alit

yan

dh

abit

at

Gen

Ban

kac

cess

ion

nu

mbe

rs

CO

I16

S

Na

not

rach

iaca

rin

ata

sp.n

ov.

WA

MS

6630

0H

tA

ust

rali

a,W

A,

EK

,la

rge

lim

esto

ne

area

wit

hn

um

erou

sgu

llie

s,40

.6km

nor

th-w

est

ofN

ich

olso

nS

tati

onH

omes

tead

,ba

seof

the

clif

fs,

Spi

nif

ex,

talu

s.U

nde

rro

cks

inlo

ose

soil

,17

°49′

30″S

,12

8°34

′40″

E(V

.Kes

sner

,1

Sep

2009

);w

et.

KC

6793

82K

C67

9329

WA

MS

4917

8P

tA

ust

rali

a,W

A,

EK

,la

rge

lim

esto

ne

area

wit

hn

um

erou

sgu

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s,40

.6km

nor

th-w

est

ofN

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nS

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onH

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tead

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seof

the

clif

fs,

Spi

nif

ex,

talu

s.U

nde

rro

cks

inlo

ose

soil

,17

°49′

30″S

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8°34

′40″

E(V

.K

essn

er,

1S

epte

mbe

r20

09);

2w

et.

KC

6793

83–8

4K

C67

9330

WA

MS

4910

0P

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a,W

A,

EK

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rge

lim

esto

ne

area

wit

hn

um

erou

sgu

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s,40

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th-w

est

ofN

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tead

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the

clif

fs,

Spi

nif

ex,

talu

s.U

nde

rro

cks

inlo

ose

soil

,17

°49′

30″S

,12

8°34

′40″

E(V

.Kes

sner

,1

Sep

2009

);85

dry.

––

Na

not

rach

iaco

ron

ata

sp.n

ov.

WA

MS

6630

1H

tA

ust

rali

a,W

A,

EK

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smon

dR

ange

,17

kmn

orth

-eas

tof

Pal

mYa

rd,

nar

row

lim

esto

ne/

san

dsto

ne

ridg

ew

ith

stee

pop

ensl

opes

,ta

lus,

and

Spi

nif

ex.

Few

bush

es.

Dea

din

litt

eran

du

nde

rro

cks,

17°1

2′13

″S,

128°

24′5

0″E

(V.K

essn

er,

29A

ug

2009

);w

et.

KC

6793

85K

C67

9331

WA

MS

4918

1P

tA

ust

rali

a,W

A,

EK

,O

smon

dR

ange

,17

kmn

orth

-eas

tof

Pal

mYa

rd,

nar

row

lim

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ne/

san

dsto

ne

ridg

ew

ith

stee

pop

ensl

opes

,ta

lus,

and

Spi

nif

ex.

Few

bush

es.

Dea

din

litt

eran

du

nde

rro

cks,

17°1

2′13

″S,

128°

24′5

0″E

(V.K

essn

er,

29A

ug

2009

);1

wet

.

KC

6793

86K

C67

9332

WA

MS

4908

6P

tA

ust

rali

a,W

A,

EK

,O

smon

dR

ange

,17

kmn

orth

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tof

Pal

mYa

rd,

nar

row

lim

esto

ne/

san

dsto

ne

ridg

ew

ith

stee

pop

ensl

opes

,ta

lus,

and

Spi

nif

ex.

Few

bush

es.

Inli

tter

and

un

der

rock

s,17

°12′

13″S

,12

8°24

′50″

E(V

.Kes

sner

,29

Au

g20

09);

11dr

y.

––

WA

MS

4908

5A

ust

rali

a,W

A,

EK

,O

smon

dR

ange

,21

.8km

nor

th-e

ast

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alm

Yard

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eep

open

slop

esan

dba

seof

lim

esto

ne

clif

fs,

Spi

nif

ex.

Dea

din

talu

s,17

°11′

13″S

,12

8°27

′18″

E(V

.Kes

sner

,29

Au

g20

09);

26dr

y.–

–

Na

not

rach

iaco

stu

lata

cost

ula

tass

p.n

ov.

WA

MS

6630

2H

tA

ust

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a,W

A,

EK

,lo

wex

pose

dh

ills

wit

hsm

all

lim

esto

ne

clif

fsof

2–3

min

hei

ght,

east

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un

can

Hig

hw

ay,

12.3

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stof

Spr

ing

Cre

ekS

tati

onH

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tead

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pin

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wfi

gtr

ees.

Un

der

slab

sin

loos

eso

il,

16°5

9′57

″S,

128°

58′3

4″E

(V.K

essn

er,

30A

ug

2009

);di

ssec

ted

spec

imen

.

KC

6793

67K

C67

9316

WA

MS

4919

1P

tA

ust

rali

a,W

A,

EK

,lo

wex

pose

dh

ills

wit

hsm

all

lim

esto

ne

clif

fsof

2–3

min

hei

ght,

east

ofD

un

can

Hig

hw

ay,

12.3

kmea

stof

Spr

ing

Cre

ekS

tati

onH

omes

tead

,S

pin

ifex

,fe

wfi

gtr

ees.

Un

der

slab

sin

loos

eso

il,

16°5

9′57

″S,

128°

58′3

4″E

(V.K

essn

er,

30A

ug

2009

);11

wet

.

KC

6793

68–6

9K

C67

9317

WA

MS

4907

3P

tA

ust

rali

a,W

A,

EK

,lo

wex

pose

dh

ills

wit

hsm

all

lim

esto

ne

clif

fsof

2–3

min

hei

ght,

east

ofD

un

can

Hig

hw

ay,

12.3

kmea

stof

Spr

ing

Cre

ekS

tati

onH

omes

tead

,S

pin

ifex

,fe

wfi

gtr

ees.

Un

der

slab

sin

loos

eso

il,

16°5

9′57

″S,

128°

58′3

4″E

(V.K

essn

er,

30A

ug

2009

);27

dry.

––

WA

MS

4917

4A

ust

rali

a,W

A,

EK

,op

enli

mes

ton

ear

eaw

ith

deep

gull

ies,

44.4

kmn

orth

ofN

ich

olso

nS

tati

onH

omes

tead

,ba

seof

the

clif

fs,

smal

lpo

cket

sof

vin

eth

icke

t,S

pin

ifex

,u

nde

rta

lus

and

slab

s,17

°37′

49″S

,12

8°53

′23″

E(V

.Kes

sner

,2

Sep

2009

);5

wet

.

KC

6793

79K

C67

9326

WA

MS

4908

7A

ust

rali

a,W

A,

EK

,op

enli

mes

ton

ear

eaw

ith

deep

gull

ies,

44.4

kmn

orth

ofN

ich

olso

nS

tati

onH

omes

tead

,ba

seof

the

clif

fs,

smal

lpo

cket

sof

vin

eth

icke

t,S

pin

ifex

,u

nde

rta

lus

and

slab

s,17

°37′

49″S

,12

8°53

′23″

E(V

.Kes

sner

,2

Sep

2009

);72

dry.

––

AM

C.4

4327

7A

ust

rali

a,W

A,

EK

,D

un

can

Roa

d,gr

ader

rubb

leu

nde

rtr

ee,

60km

nor

thof

Nic

hol

son

hom

este

ad,

un

der

lim

esto

ne

rock

s,17

°30′

03″S

,12

8°49

′15″

E(R

.Cro

oksh

anks

,28

Jan

2005

);18

dry.

––

THE NEW CAMAENID GENUS NANOTRACHIA 105


Tab

le1.

Con

tin

ued

Taxo

n

Mu

seu

mre

gist

rati

onn

um

ber

Sta

tus

Loc

alit

yan

dh

abit

at

Gen

Ban

kac

cess

ion

nu

mbe

rs

CO

I16

S

AM

C.4

4327

8A

ust

rali

a,W

A,

EK

,D

un

can

Roa

d,gr

ader

rubb

le,

58km

nor

thof

Nic

hol

son

hom

este

ad,

un

der

lim

esto

ne

rubb

le,

17°3

0′46

″S,

128°

48′4

5″E

(R.C

rook

shan

ks,

28Ja

n20

05);

7dr

y.–

–

AM

C.4

4328

7A

ust

rali

a,W

A,

EK

,74

kmn

orth

ofN

ich

olso

nH

omes

tead

,D

un

can

Roa

d,K

elly

Cre

ek,

infl

ood

debr

isof

cree

k,17

°22′

07″S

,12

8°56

′17″

E(R

.Cro

oksh

anks

,28

Jan

2005

);1

dry.

––

AM

C.4

4329

3A

ust

rali

a,W

A,

EK

,D

un

can

Roa

d,O

ldO

rdR

iver

Hom

este

ad,

For

rest

Cre

ek,

70km

nor

thof

Nic

hol

son

Hom

este

ad,

un

der

lim

esto

ne

rock

s&

con

cret

eof

old

stru

ctu

res,

17°2

3′56

″S,

128°

52′0

1″E

(R.C

rook

shan

ks,

29Ja

n20

05);

12dr

y,6

wet

.

––

WA

MS

4907

4A

ust

rali

a,W

A,

EK

,O

ldO

rdR

iver

Hom

este

adru

ins,

nor

thof

For

rest

Cre

ek,

Du

nca

nH

igh

way

,L

imes

ton

esl

abs

inth

egr

ass

nea

rol

dru

ins.

Un

der

slab

s,17

°23′

57″S

,12

8°52

′01″

E(V

.Kes

sner

,31

Au

g20

09);

50dr

y.–

–

WA

MS

4907

5A

ust

rali

a,W

A,

EK

,gu

lly

east

ofD

un

can

Hig

hw

ay,

sou

thof

Bro

okC

reek

cros

sin

g,li

mes

ton

egu

lly

inop

enw

oodl

and,

Spi

nif

ex.

Rec

entl

ybu

rned

.U

nde

rro

cks,

17°4

2′08

″S,

128°

49′3

9″E

(V.K

essn

er,

31A

ug

2009

);16

dry.

––

WA

MS

4908

8A

ust

rali

a,W

A,

EK

,op

enli

mes

ton

esl

opes

,L

ees

Cre

ekdr

ain

age,

35.6

kmn

orth

-wes

tof

Kir

kim

bie

Sta

tion

Hom

este

ad,

stee

psl

opes

and

base

ofli

mes

ton

ecl

iffs

abov

ea

stre

am,

few

bush

es.

Un

der

rock

sin

loos

eso

il,

17°3

2′48

″S,

128°

58′0

8″E

(V.K

essn

er,

2S

ep20

09);

93dr

y.

––

WA

MS

4917

5A

ust

rali

a,W

A,

EK

,op

enli

mes

ton

esl

opes

,L

ees

Cre

ekdr

ain

age,

35.6

kmn

orth

-wes

tof

Kir

kim

bie

Sta

tion

Hom

este

ad,

stee

psl

opes

and

base

ofli

mes

ton

ecl

iffs

abov

ea

stre

am,

few

bush

es.

Un

der

rock

sin

loos

eso

il,

17°3

2′48

″S,

128°

58′0

8″E

(V.K

essn

er,

2S

ep20

09);

3w

et.

KC

6793

80–8

1K

C67

9327

–28

WA

MS

4919

2A

ust

rali

a,W

A,

EK

,O

ldO

rdR

iver

Hom

este

adru

ins,

nor

thof

For

rest

Cre

ek,

Du

nca

nH

igh

way

,li

mes

ton

esl

abs

inth

egr

ass

nea

rol

dru

ins.

Un

der

slab

s,17

°23′

57″S

,12

8°52

′01″

E(V

.Kes

sner

,31

Au

g20

09);

1w

et.

––

Na

not

rach

iaco

stu

lata

mon

teji

nn

iss

p.n

ov.

NT

MP

4893

9A

ust

rali

a,N

T,V

RD

,30

.7km

sou

th-w

est

ofM

onte

jin

ni

Sta

tion

Hom

este

ad,

Mon

teji

nn

iS

tati

on,

larg

eli

mes

ton

efo

rmat

ion

s,ka

rst,

clif

fsof

6–8

min

hei

ght,

vin

eth

icke

tpa

tch

es.

Inde

epta

lus,

free

seal

er,

16°5

2′16

″S,

131°

34′1

1″E

(V.K

essn

er,

M.B

raby

,T.

Par

kin

,29

Jul2

010)

;di

ssec

ted

spec

imen

.

KC

6793

96K

C67

9340

AM

C.4

7021

4A

ust

rali

a,N

T,V

RD

,30

.7km

sou

th-w

est

ofM

onte

jin

ni

Sta

tion

Hom

este

ad,

Mon

teji

nn

iS

tati

on,

larg

eli

mes

ton

efo

rmat

ion

s,ka

rst,

clif

fsof

6–8

min

hei

ght,

vin

eth

icke

tpa

tch

es.

Inde

epta

lus,

free

seal

er,

16°5

2′16

″S,

131°

34′1

1″E

(V.K

essn

er,

M.B

raby

,T.

Par

kin

,29

Jul2

010)

;29

dry,

8w

et.

KC

6793

97–9

8K

C67

9341

–42

AM

C.4

7116

9A

ust

rali

a,N

T,C

raw

ford

Cre

ek,

Bu

chan

anH

igh

way

,17

kmN

NW

ofV

icto

ria

Riv

erD

own

sH

omes

tead

,bu

ried

inlo

ose

soil

un

der

rock

sin

smal

lli

mes

ton

eou

tcro

p,16

°16′

11″S

,13

0°57

′04″

E(V

.Kes

sner

,21

Mar

2008

);11

dry.

––

AM

C.4

6275

4A

ust

rali

a,N

T,V

RD

,16

.4km

NN

Wof

VR

DS

tati

onH

omes

tead

,B

uch

anan

Hig

hw

ay,

nea

rC

raw

ford

Cre

ekcr

ossi

ng,

pave

men

tli

mes

ton

ein

open

woo

dlan

dal

ong

hig

hw

ay.

Un

der

slab

sbu

ried

inlo

ose

soil

,16

°16′

01″S

,13

0°57

′08″

E(V

.Kes

sner

,16

Jul2

008)

;23

dry,

10w

et.

KC

6793

88–9

0H

Q24

5504

KC

6793

33–3

4

AM

C.4

7019

7A

ust

rali

a,N

T,V

RD

,17

.2km

sou

th-w

est

ofM

oun

tS

anfo

rdH

omes

tead

,G

rego

ryN

atio

nal

Par

k,lo

wli

mes

ton

eh

ill

nor

thof

ase

ason

alst

ream

inD

epot

Cre

ekdr

ain

age,

17°0

3′12

″S,

130°

24′5

4″E

(V.K

essn

er,

T.P

arki

n,

25Ju

l201

0);

24dr

y,4

wet

.

KC

6793

91–9

3K

C67

9335

–37

AM

C.4

7019

8A

ust

rali

a,N

T,V

RD

,17

.7km

sou

th-w

est

ofM

oun

tS

anfo

rdH

omes

tead

,G

rego

ryN

atio

nal

Par

k,lo

wan

dop

enli

mes

ton

eh

ill,

sou

thof

ase

ason

alst

ream

inD

epot

Cre

ekdr

ain

age.

Un

der

rock

sin

loos

eso

il,

17°0

3′11

″S,

130°

24′3

9″E

(V.K

essn

er,

T.P

arki

n,

25Ju

l201

0);

48dr

y,28

wet

.

KC

6793

94–9

5K

C67

9338

–39



AM

C.4

3765

9A

ust

rali

a,N

T,C

raw

ford

Cre

ek,

Bu

chan

anH

igh

way

,17

kmN

NW

ofV

icto

ria

Riv

erD

own

sH

omes

tead

,pa

vem

ent

lim

esto

ne,

open

woo

dlan

d,bu

ried

inso

ilu

nde

rla

rge

rock

s,16

°16′

11″S

,13

0°57

′04″

E(R

.Cro

oksh

anks

,9

Au

g20

04);

14dr

y,3

wet

.

KC

6793

87H

Q24

5586

WA

MS

2997

5A

ust

rali

a,N

T,G

rego

ryN

atio

nal

Par

k,17

.7km

sou

th-w

est

ofM

oun

tS

anfo

rdH

omes

tead

,V

RD

,lo

wan

dop

enli

mes

ton

eh

ill

sou

thof

ase

ason

alst

ream

inD

epot

Cre

ekdr

ain

age.

Un

der

rock

sin

loos

eso

il,

17°0

3′10

.6″S

,13

0°24

′38.

9″E

(V.K

essn

er,

25Ju

l201

0);

39dr

y.

––

WA

MS

2997

6A

ust

rali

a,N

T,ju

nct

ion

ofG

ill

and

Gil

es(W

atti

e)cr

eeks

,27

kmw

est

ofK

alka

rin

dji,

Dag

ura

guA

bori

gin

alL

and

Tru

st,

VR

D,

lim

esto

ne

hil

lbe

side

ast

ream

,w

ine

thic

ket,

dead

inta

lus.

17°2

3′20

.5″S

,13

0°35

′02.

8″E

(V.K

essn

er,

27Ju

l201

0);

10dr

y.

––

WA

MS

2997

7A

ust

rali

a,N

T,M

onte

jin

ni

Sta

tion

,30

.7km

sou

th-w

est

ofM

onte

jin

ni

Sta

tion

Hom

este

ad,

VR

D,

larg

eli

mes

ton

efo

rmat

ion

s,ka

rst,

clif

fsof

6–8

min

hei

ght,

vin

eth

icke

tpa

tch

es.

Un

der

talu

sin

loos

eso

il,

16°5

2′16

.1″S

,13

1°34

′10.

8″E

(V.K

essn

er,

29Ju

l201

0);

23dr

y.

––

WA

MS

2999

7A

ust

rali

a,N

T,G

rego

ryN

atio

nal

Par

k,17

.2km

sou

th-w

est

ofM

oun

tS

anfo

rdH

omes

tead

,V

RD

,lo

wli

mes

ton

eh

ill

nor

thof

ase

ason

alst

ream

inD

epot

Cre

ekdr

ain

age.

Un

der

talu

sin

loos

eso

il.

Fre

ese

aler

,17

°03′

11.7

″S,

130°

24′5

4.0″

E(V

.Kes

sner

,25

Jul2

010)

;10

dry.

––

Nan

otra

chia

inte

rmed

ia(S

olem

,19

84)

AM

C.1

4610

9P

tA

ust

rali

a,D

un

can

Hig

hw

ay,

14.3

kmso

uth

ofB

ehn

Riv

ercr

ossi

ng,

13.4

kmn

orth

ofS

prin

gC

reek

Sta

tion

turn

-off

,16

°41′

51″S

,12

8°55

′06″

E(A

.Sol

em&

L.P

rice

,13

May

1980

);3

wet

.–

–

AM

C.1

4611

0P

tA

ust

rali

a,W

A,

EK

,D

un

can

Hig

hw

ay,

14.3

kmso

uth

ofB

ehn

Riv

ercr

ossi

ng,

13.4

kmn

orth

ofS

prin

gC

reek

Sta

tion

turn

-off

,16

°41′

51″S

,12

8°55

′06″

E(A

.Sol

em&

L.P

rice

,13

May

1980

);4

dry.

––

AM

C.1

4611

1P

tA

ust

rali

a,W

A,

EK

,D

un

can

Hig

hw

ay,

9km

sou

thB

ehn

Riv

ercr

ossi

ng,

sou

thof

Ku

nu

nu

rra,

clif

fs,

16°3

9′23

″S,

128°

56′1

6″E

(A.S

olem

&L

.Pri

ce,

12M

ay19

80);

4dr

y.–

–

AM

C.4

4336

6A

ust

rali

a,W

A,

EK

,D

un

can

Hig

hw

ay,

wes

tsi

de,

8.4

kmso

uth

ofB

ehn

Riv

ercr

ossi

ng,

sou

thof

Ku

nu

nu

rra,

un

der

lim

esto

ne

rock

s,16

°39′

15″S

,12

8°56

′30″

E(V

.Kes

sner

,15

Jul1

985)

;28

dry.

––

AM

C.4

4336

7A

ust

rali

a,W

A,

EK

,D

un

can

Hig

hw

ay,

wes

tsi

de,

13.5

kmso

uth

ofB

ehn

Riv

ercr

ossi

ng,

sou

thof

Ku

nu

nu

rra,

un

der

lim

esto

ne

rock

s,16

°42′

00″S

,12

8°55

′00″

E(V

.Kes

sner

,15

Jul1

985)

;20

dry.

––

AM

C.4

7363

0A

ust

rali

a,W

A,

EK

,13

.5km

sou

thof

Beh

nR

iver

,in

dirt

un

der

lim

esto

ne

rock

s,16

°42′

04″S

,12

8°57

′58″

E(G

.R.A

nn

abel

l,15

Jul1

985)

;8

dry.

––

WA

MS

4907

2A

ust

rali

a,W

A,

EK

,li

mes

ton

eri

dge

wes

tof

Du

nca

nH

igh

way

,13

.6km

SS

Wof

Beh

nR

iver

cros

sin

g,S

prin

gC

reek

Sta

tion

,li

mes

ton

eri

dge,

patc

hes

ofvi

ne

thic

ket,

inta

lus,

16°4

1′59

″S,

128°

55′0

6″E

(V.K

essn

er,

27A

ug

2009

);30

dry.

––

WA

MS

4907

6A

ust

rali

a,W

A,

EK

,li

mes

ton

ear

eaea

stof

Mu

dS

prin

gC

reek

,w

est

ofD

un

can

Hig

hw

ay,

Spr

ing

Cre

ekS

tati

on,

open

lim

esto

ne

slop

es,

wel

l-de

velo

ped

Spi

nif

ex.

Un

der

rock

s,16

°41′

20″S

,12

8°54

′55″

E(V

.Kes

sner

,3

Sep

2009

);34

dry.

––

WA

MS

4907

7A

ust

rali

a,W

A,

EK

,ga

pin

lim

esto

ne

ridg

en

orth

ofM

ud

Spr

ing

Cre

ek,

wes

tof

Du

nca

nH

igh

way

,S

prin

gC

reek

Sta

tion

,st

eep

lim

esto

ne

slop

es,

talu

s,S

pin

ifex

.U

nde

rro

cks

inlo

ose

soil

,16

°41′

33″S

,12

8°55

′07″

E(V

.Kes

sner

,3

Sep

2009

);35

dry.

––

WA

MS

4907

9A

ust

rali

a,W

A,

EK

,li

mes

ton

egu

lly

alon

ga

seas

onal

stre

am,

29.8

kmn

orth

ofS

prin

gC

reek

Sta

tion

Hom

este

ad,

lim

esto

ne

gull

yw

ith

vin

eth

icke

tpa

tch

es.

Un

der

slab

s,in

loos

eso

ilan

dli

tter

,16

°43′

40″S

,12

8°52

′25″

E(V

.Kes

sner

,28

Au

g20

09);

357

dry.

––

WA

MS

4909

2A

ust

rali

a,W

A,

EK

,ga

pin

lim

esto

ne

ridg

e,n

orth

ofM

ud

Spr

ing

Cre

ek,

wes

tof

Du

nca

nH

igh

way

,S

prin

gC

reek

Sta

tion

,st

eep

lim

esto

ne

slop

es,

talu

s,S

pin

ifex

.U

nde

rsl

abs,

16°4

1′33

″S,

128°

55′0

7″E

(V.K

essn

er,

3S

ep20

09);

42dr

y.

––



Tab

le1.

Con

tin

ued

Taxo

n

Mu

seu

mre

gist

rati

onn

um

ber

Sta

tus

Loc

alit

yan

dh

abit

at

Gen

Ban

kac

cess

ion

nu

mbe

rs

CO

I16

S

Na

not

rach

iale

vis

sp.n

ov.

WA

MS

4919

0A

ust

rali

a,W

A,

EK

,li

mes

ton

eri

dge

wes

tof

Du

nca

nH

igh

way

,13

.6km

SS

Wof

Beh

nR

iver

cros

sin

g,S

prin

gC

reek

Sta

tion

,li

mes

ton

eri

dge,

patc

hes

ofvi

ne

thic

ket,

inta

lus,

16°4

1′59

″S,

128°

55′0

6″E

(V.K

essn

er,

27A

ug

2009

);11

wet

.

KC

6793

64–6

6K

C67

9314

–15

WA

MS

4919

3A

ust

rali

a,W

A,

EK

,li

mes

ton

ear

eaea

stof

Mu

dS

prin

gC

reek

,w

est

ofD

un

can

Hig

hw

ay,

Spr

ing

Cre

ekS

tati

on,

Ope

nli

mes

ton

esl

opes

,w

ell

deve

lope

dS

pin

ifex

.U

nde

rro

cks,

16°4

1′20

″S,

128°

54′5

5″E

(V.K

essn

er,

3S

ep20

09);

25w

et.

KC

6793

70–7

2K

C67

9318

–20

WA

MS

4919

4A

ust

rali

a,W

A,

EK

,li

mes

ton

egu

lly

alon

ga

seas

onal

stre

am,

29.8

kmn

orth

ofS

prin

gC

reek

Sta

tion

Hom

este

ad,

lim

esto

ne

gull

yw

ith

vin

eth

icke

tpa

tch

es.

Un

der

slab

s,in

loos

eso

ilan

dli

tter

,16

°43′

40″S

,12

8°52

′25″

E(V

.Kes

sner

,28

Au

g20

09);

95w

et.

KC

6793

73–7

5K

C67

9321

–22

WA

MS

4919

5A

ust

rali

a,W

A,

EK

,ga

pin

lim

esto

ne

ridg

e,n

orth

ofM

ud

Spr

ing

Cre

ek,

wes

tof

Du

nca

nH

igh

way

,S

prin

gC

reek

Sta

tion

,st

eep

lim

esto

ne

slop

es,

talu

s,S

pin

ifex

.U

nde

rro

cks

inlo

ose

soil

,16

°41′

33″S

,12

8°55

′07″

E(V

.Kes

sner

,3

Sep

2009

);16

wet

.

KC

6793

76–7

8K

C67

9323

–25

WA

MS

6630

3H

tA

ust

rali

a,W

A,

EK

,n

arro

wli

mes

ton

eri

dge

6.7

kmso

uth

-wes

tof

Lis

sade

llS

tati

onH

omes

tead

,ba

seof

the

clif

fs,

smal

lpo

cket

sof

vin

eth

icke

t,u

nde

rro

cks

inlo

ose

soil

,16

°43′

17″S

,12

8°30

′46″

E(V

.Kes

sner

,K

.Car

nes

,6

Sep

2009

);di

ssec

ted

spec

imen

.

KC

6793

55K

C70

3174

WA

MS

4919

9P

tA

ust

rali

a,W

A,

EK

,n

arro

wli

mes

ton

eri

dge

6.7

kmso

uth

-wes

tof

Lis

sade

llS

tati

onH

omes

tead

,ba

seof

the

clif

fs,

smal

lpo

cket

sof

vin

eth

icke

t,u

nde

rro

cks

inlo

ose

soil

,16

°43′

17″S

,12

8°30

′46″

E(V

.Kes

sner

,K

.Car

nes

,6

Sep

2009

);67

wet

.

KC

6793

56–5

8K

C70

3175

–77

WA

MS

4909

6P

tA

ust

rali

a,W

A,

EK

,n

arro

wli

mes

ton

eri

dge

6.7

kmso

uth

-wes

tof

Lis

sade

llS

tati

onH

omes

tead

,ba

seof

the

clif

fs,

smal

lpo

cket

sof

vin

eth

icke

t,u

nde

rro

cks

inlo

ose

soil

,16

°43′

17″S

,12

8°30

′46″

E(V

.Kes

sner

,K

.Car

nes

,6

Sep

2009

);19

0dr

y.

––

AM

C.1

4803

8A

ust

rali

a,W

A,

EK

,L

ake

Arg

yle,

sou

th-w

est

corn

er,

5km

sou

th-w

est

ofL

issa

dell

Hom

este

ad,

un

der

lim

esto

ne

rock

s,16

°42′

30″ S

,12

8°31

′30″

E(V

.Kes

sner

,17

Jul1

985)

;20

dry.

––

WA

MS

4909

4A

ust

rali

a,W

A,

EK

,L

imes

ton

eri

dge

15.4

kmso

uth

-wes

tof

Lis

sade

llS

tati

onH

omes

tead

,li

mes

ton

eri

dge,

patc

hes

ofvi

ne

thic

ket

patc

hes

,u

nde

rro

cks

inlo

ose

soil

,16

°47′

56″S

,12

8°29

′02″

E(V

.Kes

sner

,R

.Hok

kan

en,

28A

ug

2009

);87

dry.

––

WA

MS

4909

5A

ust

rali

a,W

A,

EK

,lo

wli

mes

ton

eri

dge

5.4

kmso

uth

-wes

tof

Lis

sade

llS

tati

onH

omes

tead

,ba

seof

the

clif

fs,

smal

lpo

cket

sof

vin

eth

icke

t,u

nde

rro

cks

inlo

ose

soil

,16

°42′

31″S

,12

8°30

′58″

E(V

.Kes

sner

,K

.Car

nes

,6

Sep

2009

);29

dry.

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Corporation, Dedham, MA). Sequences have beendeposited in GenBank (Tables 1, S1).

Sequence alignments were generated usingMUSCLE, as implemented in MEGA 5 (Tamura et al.,2011). Sequence saturation was assessed for eachmtDNA fragment by using tests implemented inDAMBE (Xia & Xie, 2001; Xia et al., 2003). Uncor-rected pairwise genetic distances were calculatedusing MEGA 5 under the option ‘pairwise deletionof gaps’. For phylogenetic analyses, 16S and COIsequences were concatenated into one partitioneddata set. Prior to the model-based phylogenetic analy-ses, the best-fit model of nucleotide substitution wasidentified for each gene partition separately usingthe goodness-of-fit test of substitution models imple-mented in MEGA 5. Partitioned models were appliedin the Bayesian inference (BI) analyses with param-eters estimated from the data set. Maximum likeli-hood (ML) analyses were performed by applying themore complex model of sequence evolution to theentire data set, as the program used did not allowfor data partitioning. One thousand ML bootstrapreplicates were performed in MEGA 5 to assess the

topology support of the ML tree. Bayesian posteriorprobabilities of phylogenetic trees were estimatedby running 107 generations of Metropolis-coupledMarkov chain Monte Carlo (two runs, each with fourchains, of which one was heated), as implemented byMrBayes 3.1.2 (Ronquist & Huelsenbeck, 2003). Adata partition was applied that allowed parameters tobe estimated separately for each gene fragment andfor each codon position of the COI gene. The samplingrate of the trees was 1000 generations. Generationssampled before the chain reached stationarity werediscarded as burn-in. Stationarity was reached whenthe average standard deviation of split frequenciesshown in MrBayes was less than 0.01 and the loglikelihood of sampled trees reached a stationary dis-tribution (Ronquist & Huelsenbeck, 2003).

MORPHOLOGICAL STUDIES

Morphological characters of adult shells (dimension,coloration, and sculpture) were assessed from a rep-resentative number of randomly chosen adult speci-mens from each lot (more than 60, if possible). If the

Figure 1. Distribution of Nanotrachia gen. nov., showing occurrences of studied samples in the Victoria River District(VRD), Northern Territory, and the East Kimberly (EK), Western Australia. Scale bar = 100 km.



number of available specimens from one lot was toosmall to permit meaningful statistical comparisons,we included specimens from additional collection sites(Fig. 1) in the immediate vicinity (i.e. from less than10 km distance) if these had an identical shell sculp-ture. Adults were recognized by a complete aperturallip. Shells were measured with callipers preciseto 0.1 mm. Characters measured were height (H,maximum dimension parallel with the axis of coil-ing, including lip) and diameter (D, maximum dimen-sion perpendicular to H, including lip). The numberof whorls (W), including protoconch, was countedprecisely to 0.1 intervals, as shown in Köhler(2011b: fig. 2). Values of D and H were plotted inSYSTAT 15 using the mtDNA tree topology as a con-straint. The 95% confidence ellipse option was used inorder to visualize the level of overlap in the morpho-space occupied by specimens of each clade. Values ofW were represented by means of frequency histo-grams in order to check for discontinuous distribu-tions among clades. Representatives of each mtDNAclade were dissected in order to study the genitalanatomy by use of a Leica M8 stereomicroscope withdrawing mirror. Genital anatomy was studied inbetween two (in small lots) and five specimens persample in order to confirm that morphological fea-tures were consistent in specimens from the sameclade. Anatomical features are reported in the taxo-nomic descriptions at the end of the paper; the ter-minology used is the same as that in Köhler (2011b).

ABBREVIATIONS

16S, 16S rRNA gene; AM, Australian Museum,Sydney; AMT, Australian Monsoon Tropics; BI, Baye-sian inference; COI, cytochrome c oxidase subunit Igene; D, shell diameter; dry, number of dry shells; EK,East Kimberley; ep, epiphallus; epd, epiphallus–penisconnecting duct; H, shell height; Iss, Index of substi-tution saturation; Iss.c, Index of substitution satura-tion critical value; lp, longitudinal pilasters; lsp,longitudinal pilasters with pointed corrugations; mf,muscular fibres; ML, maximum likelihood; NP,National Park; NT, Northern Territory; NTM,Museum and Art Galleries of the Northern Territory,Darwin; p, penis; rm, retractor muscle; scr, sub-circular ridge; sh, penial sheath; va, vagina; vd, vasdeferens; VRD, Victoria River District, NT; W,number of whorls of shell; WA, Western Australia;WAM, Western Australian Museum, Perth; wet,number of ethanol-preserved specimens.

RESULTSMOLECULAR ANALYSES

Analyses of mitochondrial sequences were employed toestimate the levels of genetic variation within and

between species, to infer phylogenetic relationshipsof confamilial species studied here, and to test themonophyly of taxa as delimited by means of theirmorphology. A pilot analysis was performed using acomprehensive 16S data set containing representativesequences from all north-western Australian camaenidgenera (tree not shown). Based on the topology of thisinitial phylogeny, we selected a group of more closelyrelated taxa, including species of the focal group and asuitable out-group (i.e. a lineage closely related to thein-group), for a final, more thorough phylogeneticanalysis. The final data set contained concatenatedCOI and 16S sequences from 90 camaenid specimensfrom the NT and WA, which represented 13 differentgenera, including the putatively new genus. Sequencesof the Kimberley endemic Kimboraga were used as anout-group to root the tree (Table S1). Eighty-sevenspecimens were represented in the data set bysequences from both genes and four by COI sequencesonly, but 16S sequences were always available for atleast another specimen from the same lot. The missingsequence fragments were coded as unknown. The finalconcatenated data set of aligned sequences of COI and16S had a total length of 1459 bp (16S, 804 bp; COI,655 bp). Tests conducted by Xia et al. (2003) indicatedno or little saturation in both mitochondrial fragments(Iss < Iss.c with P < 0.01). The goodness-of-fit testrevealed the TN93 model (Tamura & Nei, 1993) withgamma distribution and proportions of invariable sites(TN93 + G + I) as the best-fit model of sequence evolu-tion for both gene fragments by means of the Bayesianinformation criterion. TN93 + G + I was used in all MLanalyses, but because this model is not implementedin MrBayes, the model GTR+G + I was used in BIanalyses.

The BI and ML analyses produced trees with nearlyidentical topologies. Therefore only the BI tree isshown (Fig. 2). For clarity, the phylogenetic clades inthis tree have been labelled with the names of taxarecognized or described below, based on comparativeanalyses of morphological and molecular data. In bothphylogenies the species of the new camaenid genusformed a clade, here labelled ‘Nanotrachia’, whichalso included the two species Ordtrachia intermediaSolem, 1984 and Mouldingia orientalis Solem, 1984.The monophyly of this clade was highly supported bymeans of Bayesian posterior clade probabilities andmaximum-likelihood bootstrapping. Within this clade,the sister pair of ‘Nanotrachia coronata sp. nov.’ and‘Nanotrachia carinata sp. nov.’ formed the sister cladeof all remaining species, which also formed two sisterclades, with Mouldingia orientalis and ‘Nanotrachialevis sp. nov.’ being the sister clade of Ordtrachiaintermedia and ‘Nanotrachia costulata’.

Additional species of Ordtrachia Solem, 1984 andMouldingia Solem, 1984 each formed distinct clades



within an essentially unresolved basal polytomy, com-prising some additional clades that represent variouscamaenid genera from throughout the region. Threespecies of Ordtrachia (Ordtrachia australis Solem,1984, Ordtrachia elegans Solem, 1984, and Ordtrachiagrandis Solem, 1984) formed the sister clade of Exili-gada, whereas Mouldingia occidentalis Solem, 1984,

type species of the genus Mouldingia, formed the sisterlineage of Westraltrachia Iredale, 1933 (Fig. 2).

Species of Nanotrachia gen. nov. as herein delim-ited by means of comparative analyses of morphologi-cal and mitochondrial differentiation differed fromeach other by mean pairwise p-distances of between6 and 18% (average = 16%) in 16S and 9 and 15%

Figure 2. Bayesian phylogram based on analyses of concatenated COI and 16S sequences. Nodal support (%): Bayesianposterior clade probabilities (BPP, above branches), ML bootstrap (BTSP, below branches); only BPP values � 90% andBTSP values � 70% are shown; asterisks = 100%.



(average = 13%) in COI (Table 2). There was nooverlap between intra- and interspecific geneticp-distances in COI, as the maximum intraspecificp-distance was 8%. By contrast, intra- and interspe-cific p-distances in 16S overlapped only slightly,at ~9%.

MORPHOLOGICAL ANALYSES

Morphological examinations and analyses of shelldimensions aimed to document and evaluate the levelof morphological differentiation within and betweenNanotrachia species. For clarity, the following ana-tomical comparisons are presented with referenceto the taxon names; however, the underlying taxon

delimitations resulted from combined analyses ofmolecular and anatomical differentiation, and werenot foregone conclusions preceding these analyses.

Species of Nanotrachia gen. nov. exhibit character-istic shells, which can readily be distinguished fromshells of other genera by the combination of keycharacters, such as small size, flat shape, openumbilicus, ribbed sculpture, mostly keeled periphery,and microscopic pustulation. Within Nanotrachiagen. nov., species varied very little in shell dimensionsand whorl counts (Table 3). In a scatter plot of H/Dmost species could not be differentiated. Only shells ofN. coronata sp. nov. could be partially distinguishedfrom other species by having the largest size rangeamong all congeners (Fig. 3A). Consequently, shell

Table 2. Genetic differentiation among clades of Nanotrachia gen. nov. by means of p-distances

ori lev int cos car cor

ori 16S 0.002COI 0.006

lev 16S 0.109 0.096COI 0.118 0.081

int 16S 0.144 0.165 0.051COI 0.135 0.144 0.054

cos 16S 0.141 0.155 0.108 0.036COI 0.139 0.139 0.093 0.040

car 16S 0.165 0.176 0.179 0.180 0.001COI 0.136 0.147 0.138 0.145 0.002

cor 16S 0.167 0.181 0.185 0.185 0.060 0.007COI 0.149 0.153 0.130 0.110 0.096 0.003

Min Max Mean

16S Within 0.001 0.096 0.032Between 0.060 0.185 0.156

COI Within 0.002 0.081 0.031Between 0.093 0.153 0.131

Entries in bold: distances within clade. Rows on top, 16S distances; rows below, COI distances. Inset: minimum,maximum, and average p-distances between and within (car, Nanotrachia carinata sp. nov.; cor, Nanotrachiacoronata sp. nov.; cos, Nanotrachia costulata sp. nov.; int, Nanotrachia intermedia; ori, Nanotrachia orientalis).

Table 3. Shell dimensions (mm) and whorl counts of Nanotrachia gen. nov. species recognized in the present work

Species N H D W

Nanotrachia carinata sp. nov. 60 3.0–4.5 (3.6 ± 0.3) 8.1–10.2 (8.8 ± 0.4) 3.5–4.0 (3.7 ± 0.1)Nanotrachia coronata sp. nov. 26 3.6–6.1 (5.1 ± 0.5) 9.7–13.4 (11.4 ± 1.0) 3.6–4.2 (4.0 ± 0.2)Nanotrachia costulata sp. nov. 132 3.5–6.0 (4.6 ± 0.5) 7.5–10.0 (8.8 ± 0.6) 3.3–4.2 (3.8 ± 0.2)Nanotrachia intermedia 60 3.4–5.3 (4.3 ± 0.4) 7.4–10.0 (8.7 ± 0.5) 3.2–4.1 (3.7 ± 0.2)Nanotrachia levis sp. nov. 100 3.4–5.3 (4.1 ± 0.4) 8.0–10.8 (9.4 ± 0.6) 3.3–4.0 (3.7 ± 0.1)Nanotrachia orientalis 70 3.2–5.5 (4.2 ± 0.5) 8.9–12.2 (10.1 ± 0.7) 3.3–4.9 (3.7 ± 0.2)Genus 348 3.0–6.1 (4.3 ± 0.4) 7.4–13.4 (9.5 ± 0.6) 3.2–4.9 (3.7 ± 0.2)

Data are min–max (average ± standard deviation) mm for N measured shells.



dimensions were generally uninformative withrespect to differentiating morphospecies. In contrast,species were found to exhibit a distinct macroscopic(and, to a lesser extent, microscopic) shell sculpture,but revealed little intraspecific sculptural variation.Most conspicuously, species differed in the presence,development, spacing, and shape of axial ribs, and theabsence or presence of a peripheral keel. For details,refer to the taxonomic descriptions and the identifi-cation key below.

Nanotrachia gen. nov. is also characterized bykey morphological features of the penial anatomy.Differentiating penial characters common to allclades include: a delicate, membranous penial sheath,tightly enclosing the entire penial complex, includingthe epiphallus; a well-developed epiphallus withoutepiphallic flagellum; attachment of the penial retrac-tor muscle at the distal end of the epiphallus; acomparatively thick vas deferens; and an essentially

smooth inner penial wall, supporting between oneand four longitudinal pilasters of variable shape anddevelopment. Particularly informative characters atthe species level were: length of epiphallus relativeto penis (one-quarter to same length); and number,shape, and development of longitudinal pilasters ofinner penial wall. For a more detailed description ofpenial characteristics refer to the taxonomic descrip-tions below. Penial features were generally foundto vary little within species. Exceptionally, withinN. costulata sp. nov. the number and arrangementof longitudinal pilasters differed between specimenscollected in the western and in the eastern parts of itsdistribution, indicating their distinctiveness.

DISCUSSION

Our operational criterion of species delimitation is todetermine phenotypically and genotypically distinct

Figure 3. A–D. H/D scatter plots with 95% confidence ellipses. A, All species; B, Nanotrachia intermedia (Solem, 1984)and N. costulata sp. nov.; C, N. orientalis (Solem, 1984) and N. levis sp. nov.; D, N. carinata sp. nov. andN. coronata sp. nov.



clusters (Sites & Marshall, 2004). To this end, weemployed a stepwise evaluation of the mitochondrialand morphological variation (‘reciprocal corrobora-tion’) to recognize distinct species by using four crite-ria: (1) distinct species form clades; (2) these cladesare well differentiated from other such clades; (3) themorphology of species differs in at least one featurethat is unlikely to be polymorphic or under environ-mental control; (4) no intermediate morphs exist. Thisprocedure is considered a conservative approach inspecies delimitation. As it requires consistent differen-tiation in morphological and mitochondrial markers,it would not recognize morphologically cryptic speciesor phylogenetically young species that share ancestralgenetic polymorphisms. By combining the observa-tions on shell and penial morphology with distribu-tional and phylogenetic data, we delineated sixmorphologically and phylogenetically distinct clusters,which are considered to represent distinct species.Two of these clusters represented the already namedspecies M. orientalis and O. intermedia. In addition,we recognized a further four species, which are cur-rently undescribed; for taxonomic descriptions refer tothe taxonomic descriptions below. All six species haveallopatric distributions in the VRD and EK (Fig. 1).

All Nanotrachia species featured shells with asimilar shape, size, colour, and microsculpture. Onlyone species, N. coronata sp. nov., could readily be dis-tinguished from all others by its significantly largershell (Fig. 3A). The remaining species had shellsof nearly identical size, shape, microsculpture, andcolour. They differed, however, most conspicuouslyin their macroscopic sculpture (Fig. 4; for N. orientalisand N. intermedia refer to Solem, 1984: 645, pl. 53a–f; 660, pl. 56d–f). The main sculptural elements,axial ribs and spiral keel, were present in all species,excepting N. levis sp. nov., which exhibits a rathersmooth shell. Nanotrachia costulata costulata ssp.nov., Nanotrachia costulata montejinnissp. nov., andN. intermedia revealed no differences in shell sculp-ture, and could only be distinguished by their distinctpenial anatomy.

The present study confirms the taxonomic utility ofpenial anatomy in camaenid taxonomy as a morpho-logical feature largely independent from morphologi-cal adaptations to the immediate environment. Penialanatomy has frequently been found to be one of thekey characters in shell-wise very similar camaenidland snails (e.g. Solem, 1985b; Köhler, 2010, 2011a, b,c, 2012; Criscione et al., 2012; Köhler & Johnson,2012; Köhler & Shea, 2012; Criscione & Köhler,2013a, b). The most informative penial features inNanotrachia were the length of the epiphallus rela-tive to the penis and the number, shape, and devel-opment of penial wall pilasters. However, two specieshad an identical penial morphology, N. carinata

sp. nov. and N. coronata sp. nov., and can only be dif-ferentiated by means of their shell.

Analysing the differentiation in mitochondrialmarkers provided us with an estimate of geneticdistinctiveness independent of morphological observa-tions, and confirmed that the species recognized bytheir morphology were also genetically distinct. Theobserved levels of interspecific differentiation wereequal to or even larger than those in other confamilialgroups in north-western Australia (Table 2). Previousstudies of Australian camaenids revealed maximalintraspecific p-distances of ~3% in Exiligada (Criscioneet al., 2012), ~4% in Rhagada (Johnson et al., 2012),and ~6% in Amplirhagada (Köhler & Johnson, 2012),with no or little overlap with interspecific distances.These values are also comparable with a maximumintraspecific divergence of ~4% in several other sty-lommatophorans (Davison, Blackie & Scothern, 2009).

One species in particular, N. levis sp. nov., sticksout from the crowd by revealing unusually highintraspecific genetic divergence, with p-distances ofup to almost 10% in 16S. Significant genetic struc-turing within and between populations of this speciesoccurred on a very small geographic scale (Fig. 1). Thegenetic differentiation amongst N. levis sp. nov. popu-lations is indeed comparable with the differentiationbetween other species of Nanotrachia. However, agreat deal of differentiation can be found, even withina single population (WAM S49199) that contains twoout of four haplotype clusters. Although we acknowl-edge that this genetic differentiation might be indica-tive of the existence of further cryptic species, weprefer taking a conservative approach. In accordancewith the four criteria of species delimitation statedabove, we consider all populations as conspecific forthe absence of morphological differentiation. Therecognition of potentially cryptic species throughanalysis of genetic differentiation alone would requireanalysing many more sequences, in order to testwhether populations share distinct haplotypes or not.Because we have only a few specimens to hand, weare unable to perform such tests and have refrainedfrom further splitting this taxon.

Two further species revealed considerable intraspe-cific genetic structuring, although on a lower scale.Firstly, N. intermedia has been found to comprisetwo distinct mitochondrial clades (Fig. 2). As in N. le-vis sp. nov., this genetic differentiation is associatedwith small geographic distances between populationsand morphological homogeneity (Fig. 6A, B). Thegenetic differentiation is therefore not translated intoa formal taxonomic act. Secondly, N. costulata sp. nov.revealed considerable intraspecific genetic structur-ing, with all sequences but one clustering in twoseparate clades. However, in contrast to the formertwo species, the genetic differentiation follows a clear



geographic pattern, and is associated with the mor-phological distinctiveness of both clades. The twoclades contain populations from the eastern andwestern portions, respectively, of the vast range ofN. costulata sp. nov., which exhibit clearly distinctpenial morphology but identical shells (Fig. 4D,7A–D). Because one sequence from the western part

of the range does not cluster with all the others, butis found at an unresolved position between the twoclades, we cannot ascertain that there is no continu-ing gene flow between the two morphologically andgeographically different forms. In recognition of thenearly coherent morphological and genetic differen-tiation, we consider the treatment of both forms as

Figure 4. Shells of Nanotrachia species studied herein. A, N. intermedia (Solem, 1984) (paratype AM C.146110); B,Nanotrachia carinata sp. nov. (paratype WAM S49100); C, N. coronata sp. nov. (paratype WAM S49086); D, N.costulata costulata sp. nov. (WAM S49088); E, N. levis sp. nov. (paratype WAM S49096); F, N. orientalis (Solem, 1984)(paratype AM C.146105); G, Mouldingia occidentalis (Solem, 1984) (paratype AM C.146107). Scale bar = 1 cm.



subspecies as the most appropriate taxonomic solu-tion to this problem for the time being.

Relatively low genetic divergence was recordedbetween N. carinata sp. nov. and N. coronata sp. nov.The two sister species also had identical genitalanatomy; however, they are recognized as distinct

species for their considerably different shells (Figs 3D,4B, C, 5A–D).

In summary, future studies should aim at a morecomprehensive sampling of haplotypes throughoutthe range of Nanotrachia in order to further test ourcurrent species delimitations. As we have taken a

Figure 5. SEM micrographs of shells showing protoconch and teleoconch microsculpture. A–B, N. carinatasp. nov. (paratype WAM S49100); C–D, N. coronata sp. nov. (paratype WAM S49086); E–F, Nanotrachia costulatasp. nov. (WAM S49088); G–H, N. levis sp. nov. (paratype WAM S49096). Scale bars: A, C, E, G = 1 mm; B, D, F,H = 200 mm.



conservative approach here, such studies may indeedresult in the recognition of additional, currentlyunrecognized, species.

The formal recognition of Nanotrachia as a distinctand undescribed genus is strongly corroborated bymorphological and phylogenetic data. We demon-strated that all species shared consistent morphologi-cal features, which set them apart from otherconfamilial genera known from the VRD and EK.These features most conspicuously comprise: a small,flat shell with axial ribs and a penis with membranouspenial sheath, well-developed epiphallus and peculiarpenial wall sculpture. Moreover, all six species formeda highly supported clade in the molecular phylogeny(Fig. 2). This clade comprises three subclades, eachcomposed by two sister species: N. carinata sp. nov.and N. coronata sp. nov., N. levis sp. nov. and N. orien-talis, and N. intermedia and N. costulata sp. nov.

In order to retain the monophyly of Nanotrachia,two species originally affiliated with other genera arebeing transferred into the new genus: O. intermediaand M. orientalis. These two species exhibit key mor-phological features typical of Nanotrachia. Thepresent phylogeny also supports their distinctivenessfrom other species of these genera, such as M.occidentalis (type species of Mouldingia) as wellas O. australis, O. elegans, and O. grandis (the typespecies of Ordtrachia is Ordtrachia septentrionalisSolem, 1985, which has not been studied here).

TAXONOMIC DESCRIPTIONSGASTROPODA

STYLOMMATOPHORA

CAMAENIDAE PILSBRY, 1895

NANOTRACHIA GEN. NOV.Type species: Ordtrachia intermedia Solem, 1984.

DescriptionShell (Figs 4, 5): Relatively small, flat, thin to mod-erately thick; periphery rounded to strongly keeled;spire moderately to weakly elevated; umbilicus open,wide, rarely partly concealed by columellar reflection;protoconch and teleoconch with dense, pointed peri-ostracal projections and fine axial growth lines;teleoconch with or without axial ribs; last whorl mod-erately wide in cross section; apertural lip reflected,moderately expanded, without lip nodes; parietal wallthin; colour uniform, horn to brown.

Genitalia (Figs 6, 7): Spermoviduct, lacking diver-ticulum and stimulatory organs. Penial sheathwell-developed, extending entire length of penis,membranous. Penial retractor muscle inserting onvas–epiphallic junction; in some species muscular

fibres extending onto penial apex. Epiphallus welldeveloped; wall comprising thick layers of muscle;connected to penis through simple duct and pore;length equivalent to 20–100% of penis. Vas deferensentering penial sheath basally to halfway up, beforereflexing into epiphallus. Penis thin with thin wall;not coiled within penial sheath; inner penial wallwith between one and three narrow to thick, straightor winding, longitudinal pilasters, in some specieswith regularly spaced, pointed corrugations. Vaginallength equivalent to 50–100% of penis, twice as longas free oviduct. Bursa copulatrix simple, distallyslightly inflated, comparatively short, extending to, ornearly to, anterior end of spermoviduct.

Comparative remarksShell easily distinguished from other camaenidgenera from the VRD and EK by its small size, flatshape, open umbilicus, microscopic pustulation. Dif-fering from Cristilabrum Solem, 1981, Exiligada,Mesodontrachia, Ningbingia Solem, 1981, Nodula-bium Criscione & Köhler, 2013, Ototrachia Criscione& Köhler, 2013, Prototrachia Solem, 1984, Pseu-domesodontrachia Criscione & Köhler, 2013, Turgen-itubulus Solem, 1981, and Vincentrachia Criscione &

Figure 6. Penial anatomy. A, Nanotrachia intermedia(Solem, 1984) (WAM S49195); B, N. intermedia (Solem,1984) (WAM S49194); C, Nanotrachia carinata sp. nov.(holotype WAM S66300); D, N. levis sp. nov. (holotypeWAM S6630). Insets showing schematic cross section ofmid-penis. Scale bar = 2 mm.



Köhler, 2013 by smaller and less conical shape. Dif-fering from most Ordtrachia species by smaller sizeand presence of axial ribs, and from O. elegans bystronger axial sculpture and periostracal projections.Differing from M. occidentalis (Fig. 4G) by callus notdetached from parietal wall.

NANOTRACHIA INTERMEDIA (SOLEM, 1984)

Ordtrachia intermedia Solem, 1984: 666–669, pl. 56,figures 172–173.

Material examined: Table 1.

DiagnosisShell (Fig. 4A): Average in size; periphery shouldered,weakly keeled; spire moderately elevated; umbilicusopen, wide, sometimes partly concealed by columellarreflection; protoconch and teleoconch with dense,pointed periostracal projections and fine axial growthlines; teleoconch with blunt, regular, widely spacedaxial ribs; apertural lip reflected, moderatelyexpanded; horn.

Genitalia (Fig. 6A, B): Penial retractor muscle insert-ing on vas–epiphallic junction. Epiphallus about aslong as penis, thick, tapering in thickness towards

penis. Muscle fibres connecting median portion ofepiphallus to penial apex. Vas deferens enteringpenial sheath halfway up. Inner penial wall with asingle, wide, long, irregularly S-shaped pilaster, com-prising apical two-thirds of wall. Vagina about as longas penis, from half to twice as long as free oviduct.

Comparative remarksShell similar to N. costulata sp. nov., differing fromN. carinata sp. nov., N. coronata sp. nov., and N. ori-entalis by less developed peripheral keel, and fromN. levis sp. nov. by presence of axial ribs. Genitalanatomy differing from N. carinata sp. nov., N. coro-nata sp. nov., and N. levis sp. nov. by smooth penialwall pilasters and long epiphallus; differing fromN. costulata sp. nov. by fewer number of pilasters (oneinstead of three).

Taxonomic remarksType species of Nanotrachia gen. nov., not congenericwith other species originally assigned to the genusOrdtrachia, as revealed by the molecular phylogeny(Fig. 2).

NANOTRACHIA CARINATA SP. NOV.HolotypeAustralia, WA, EK, 40.6 km north-west of NicholsonStation Homestead, limestone area with numerousgullies, base of cliffs, Spinifex, and talus, underrocks in loose soil, 17°49′30″S, 128°34′40″E (coll.V. Kessner, 1 September 2009); dissected specimen(WAM S66300).

ParatypesSame data as holotype; two wet (WAM S49178), 85dry (WAM S49100).

EtymologyIn reference to the peripheral keel of the shell,derived from ‘carinatus’ (Latin = possessing a keel),adjective of feminine gender.

DescriptionShell (Figs 4B, 5A, B): Average in size; peripheryshouldered, strongly keeled; spire weakly elevated;umbilicus open, wide, not concealed by columellarreflection; protoconch and teleoconch with dense,pointed periostracal projections and fine axial growthlines; teleoconch with weak, blunt, narrowly spacedaxial ribs, interrupted on keel; apertural lip reflected,moderately expanded; yellowish–horn.

Genitalia (Fig. 6C): Epiphallus very short, one-quarter of penial length; no muscle fibres connect theepiphallus and penial apex. Vas deferens entering

Figure 7. Intraspecific variation of penial anatomy in N.costulata sp. nov. A, Nanotrachia c. costulata (holo-type WAM S66302); B, Nanotrachia c. costulata (WAMS49174); C, Nanotrachia c. montejinni ssp. nov. (holo-type NTM P48939); D, Nanotrachia c. montejinni (AMC.437659). Insets showing schematic cross section of mid-penis. Scale bar = 2 mm.



penial sheath almost halfway up. Penial wall thin,with two longitudinal pilasters, one wide, irregular,comprising half of penial wall, second pilasterthinner, irregularly shaped, winding, with regularlyspaced, pointed corrugations; penial pore surroundedby subcircular ridge. Vagina slightly shorter thanpenis, half to twice as long as free oviduct.

Comparative remarksShell similar to N. coronata sp. nov., but smaller insize, axial ribs interrupted on keel. Differs from N. le-vis sp. nov. by presence of keel, from all other conge-ners by less developed axial ribs. The largest shells ofN. carinata sp. nov. are similar to the smallest shellsof O. elegans, which differ by more elevated spire andweaker developed periostracal projections. Genitaliaidentical to N. coronata sp. nov., N. levis sp. nov. hasthree pilasters, and all other species have smoothpilasters.

NANOTRACHIA CORONATA SP. NOV.HolotypeAustralia, WA, EK, Osmond Range, 17 km north-east of Palm Yard, narrow limestone and sandstoneridge, with steep open slopes, talus, and Spinifex, inlitter under rocks, 17°12′13″S, 128°24′50″E (coll.V. Kessner, 29 August 2009); dissected specimen(WAM S66301).

ParatypesSame as holotype; one wet (WAM S49181), 11 dry(WAM S49086).

Other material: Table 1.

EtymologyIn reference to the crown-like appearance of theperipheral keel because of the axial ribs continuingonto it, derived from ‘coronatus’ (Latin = bearing acrown), adjective of feminine gender.

DescriptionShell (Figs 4C, 5C, D): Large; periphery shouldered,strongly keeled; spire weakly elevated; umbilicusopen, wide, not concealed by columellar reflection;protoconch and teleoconch with dense, pointed peri-ostracal projections and fine axial growth lines; tele-oconch with weak, blunt, widely spaced axial ribs, notinterrupted on keel; apertural lip reflected, moder-ately expanded; yellowish brown.

Genitalia: Epiphallus very short, one-quarter ofpenial length; no muscle fibres connect epiphallus andpenial apex. Vas deferens entering penial sheathalmost halfway up. Penial wall thin, with two longi-

tudinal pilasters, one wide, irregular, comprising halfof penial wall, second pilaster thinner, irregularlyshaped, winding, with regularly spaced, pointed cor-rugations; penial pore surrounded by subcircularridge. Vagina slightly shorter than penis, half to twiceas long as free oviduct (identical to N. carinatasp. nov.; Fig. 6C).

Comparative remarksLargest species of genus. Shell similar to N. carina-ta sp. nov., but axial ribs continuing on keel; N. le-vis sp. nov. differing by absence of keel; N. orientaliswith stronger ribs, other congeners with weaker keel.Genitalia identical to N. carinata sp. nov.

NANOTRACHIA COSTULATA SP. NOV.Two subspecies are described herein. The nominateform occurs in the EK, comprising the western part ofthe range. The second subspecies occurs in the VRD,comprising the eastern part of the range. Both sub-species share identical shells but differ in develop-ment of inner penial wall pilasters.

NANOTRACHIA COSTULATA COSTULATA SSP. NOV.HolotypeAustralia, WA, EK, 12.3 km east of Spring CreekStation Homestead, east of Duncan Highway,low exposed hills with limestone cliffs of 2–3 min height, Spinifex, few fig trees, under slabs inloose soil, 16°59′57″S, 128°58′34″E (coll. V. Kessner,30 August 2009); dissected specimen (WAM S66302).

ParatypesSame as holotype; 11 wet (WAM S49191), 11 dry(WAM S49073).


EtymologyIn reference to the shell sculpture of axial ribs,derived from ‘costulatus’ (Latin = exhibiting ribs),adjective of feminine gender.

DescriptionShell (Figs 4D, 5E, F): Average in size; peripheryshouldered, weakly keeled; spire weakly elevated;umbilicus open, wide, sometimes partly concealed bycolumellar reflection; protoconch and teleoconch withdense, pointed periostracal projections and fine axialgrowth lines; teleoconch with prominent, blunt,widely spaced axial ribs; apertural lip reflected, mod-erately expanded; horn.



Genitalia (Fig. 7A, B): Epiphallus long, thick, taper-ing in thickness, length equivalent to 50–70% ofpenis; thick muscular fibres connecting distal portionof epiphallus to penial apex. Vas deferens enteringpenial sheath almost halfway up. Inner penial wallwith up to four, mostly narrow, nearly straight longi-tudinal pilasters comprising entire length of penialwall.

Vagina half as long as penis, half to twice as long asfree oviduct.

Comparative remarksShell similar to N. intermedia both in size and shape,differing from N. carinata sp. nov., N. coronata sp.nov., and N. orientalis by less developed keel, andfrom N. levis sp. nov. by presence of axial ribs. Geni-talia of N. carinata sp. nov., N. coronata sp. nov., andN. levis sp. nov. differ by having corrugated penialwall pilasters; N. intermedia has only one penial wallpilaster.

NANOTRACHIA COSTULATA MONTEJINNI SSP. NOV.HolotypeAustralia, NT, VRD, 30.7 km south-west of Monte-jinni Station Homestead, Montejinni Station, largelimestone formations, karst, cliffs of 6–8 m inheight, vine thicket patches. In deep talus, freesealer, 16°52′16″S, 131°34′11″E (V. Kessner, M.Braby, T. Parkin, 29 July 2010); dissected specimen(NTM P48939).

ParatypesSame as holotype; 29 dry, eight wet (AM C.470214)


EtymologyFor the type locality, Montejinni Station, noun byapposition.

DescriptionAs nominate form, but with longer, wider epiphallus;inner penial wall with two thick, winding, irregularlyshaped longitudinal pilasters (Fig. 7C, D).

Comparative remarksDiffers from nominate form by shape, number, anddevelopment of penial wall pilasters.

NANOTRACHIA LEVIS SP. NOV.HolotypeAustralia, WA, EK, 6.7 km south-west of LissadellStation Homestead, narrow limestone ridge, base ofcliffs, small pockets of vine thicket, under rocks in

loose soil, 16°43′17″S, 128°30′46″E (coll. V. Kessner,K. Carnes, 6 September 2009); dissected specimen(WAM S66303).

ParatypesSame as holotype; 67 wet (WAM S49199), 109 dry(WAM S49096).


EtymologyIn reference to the smooth shell surface and lackof axial sculpture, derived from ‘levis’ (Latin =smooth); adjective of feminine gender.

DescriptionShell (Figs 4E, 5G, H): Average in size, peripheryrounded, without keel; spire weakly elevated; umbili-cus open, wide, not concealed by columellar reflection;protoconch and teleoconch with dense, pointedperiostracal projections and fine axial growth lines;teleoconch without ribs; apertural lip reflected, mod-erately expanded; horn to light brown.

Genitalia (Fig. 6D): Epiphallus very short, onefifth of penial length; no muscle fibres connectingepiphallus with penis apex. Inner penial wall withtwo longitudinal pilasters, one thick, tapering inwidth towards base, with weak projection, notreaching proximal end of wall, second pilasterthinner, with pointed corrugations, extending entirelength of wall. Vagina half as long as penis, as longas free oviduct.

Comparative remarksShell differing from other congeners by absenceof axial sculpture. Genitalia similar to N. carinatasp. nov. and N. coronata sp. nov., but differing byshape and size of pilasters (one being narrower andlonger, the other being straight); differing from allother congeners by presence of pointed corrugations.

NANOTRACHIA ORIENTALIS (SOLEM, 1984)

Mouldingia orientalis Solem, 1984: 644–647, pl. 53,figures 163d–f, 165.

Material examined: Table 1.

DiagnosisShell (Fig. 4F): Average in size; periphery shouldered,strongly keeled; spire weakly elevated; umbilicusopen, wide, not concealed by columellar reflection;protoconch and teleoconch with dense, pointedperiostracal projections and fine axial growth lines;



teleoconch with prominent blade-shaped, irregular,widely spaced axial ribs; apertural lip reflected, mod-erately expanded; brown.

Genitalia: Refer to Solem (1984: 647).

Comparative remarksShell differing from other congeners by blade-shaped axial ribs. Penial wall differing from

other congeners by more numerous and narrowerpilasters.

Taxonomic remarksOriginally assigned to Mouldingia by Solem (1984)for its shell being extremely similar with the typespecies, M. occidentalis (Fig. 4G), from which it canonly be distinguished by parietal lip being attachedto callus.

KEY TO THE IDENTIFICATION OF SPECIES OF NANOTRACHIA

1. a. Peripheral keel and axial ribs present...............................................................................................2b. Peripheral keel and axial ribs absent ...........................................................Nanotrachia levis sp. nov.

2. a. Axial ribs regularly spaced and blunt ............................................................................................... 3b. Axial ribs irregularly spaced and blade-shaped.......................................................Nanotrachia orientalis

3. a. Peripheral keel marked and acutely angled........................................................................................4b. Peripheral keel week and obtuse......................................................................................................5

4. a. Axial ribs continuing onto keel; D ~10 mm or larger.................................Nanotrachia coronata sp. nov.b. Axial ribs not continuing onto keel; D up to ~10 mm................................Nanotrachia carinata sp. nov.

5. a. One single longitudinal pilaster on inner penial wall.............................................Nanotrachia intermediab. More than one single longitudinal pilaster on inner penial wall.................Nanotrachia costulata sp. nov.

ACKNOWLEDGEMENTS

This work has been made possible through financialsupport from the Australian Government (ABRSgrants RF210-05 and RF 211-10 to FK). VinceKessner (Adelaide River) and Michael Braby(Darwin) prepared and conducted the fieldwork,thereby providing the foundation for this work. Theirefforts are most thankfully acknowledged. Specialthanks are due to Martin Püschel (Berlin) for produc-ing illustrations of genitalia and to Sue Lindsay (AM)for conducting SEM work. We thank three reviewersfor constructively commenting on an earlier version ofthis article.

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SUPPORTING INFORMATION

Additional Supporting Information may be found in the online version of this article at the publisher’s web-site:

Table S1. Museum registration numbers and GenBank accession numbers of samples used as out-groups.



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