Taxonomic review of the genus Orchymontia (Coleoptera: Hydraenidae)

Taxonomic review of the genus Orchymontia (Coleoptera: Hydraenidae)Juan A. Delgado Departamento de Biología Animal (Zoología), Facultad de Biología, Universidad de Murcia,30100 Murcia, Spain.Ricardo L. Palma Museum of New Zealand Te Papa Tongarewa, PO Box 467, Wellington, New Zealand.

AbstractAll the species of the genus Orchymontia Broun,

1919 are reviewed, including O. nunni described asa new species from Karori,Wellington.The malegenitalia of all 14 species are discussed and figuredin both lateral and ventral views. A new arrange-ment of the species in groups and subgroups isproposed, mainly based on the morphology of themale genitalia and supported by features of themale middle tibiae. New locality records are givenfor 5 species.

Key words: Hydraenidae, Orchymontia, newspecies, locality records, male genitalia,New Zealand.

IntroductionThe genus Orchymontia was described by Broun

(1919) for the single species O. spinipennis Broun,1919. In his revision of the New ZealandHydraenidae, Ordish (1984) redescribedOrchymontia and described 12 new species. Hansen(1991) gave a complete redescription ofOrchymontia in his generic review of the familyHydraenidae. Perkins (1997) erected the new sub-family Orchymontinae - with Orchymontia as typegenus - for the three endemic genera of New Zealand Hydraenidae.

Recent collections of Orchymontia beetles madeby us and by John Nunn in both the North and theSouth Islands include an undescribed species andnew locality records.The new species was recognised after we compared its genitalia withthose of all previously known species. Ordish(1984) included figures of genitalia from eight ofthe 13 species he described or redescribed,presumably because he found the remaining five tobe so similar to other species that they did notwarrant illustration.While we agree with Ordish(1984: 22) in that the species of Orchymontia aremorphologically uniform, we believe that the male genitalia alone are sufficiently distinct to separateall species.This is consistent with several otherhydraenid genera such as those studied by Jäch(1993, 1994), Perkins (1980) and Perkins &Balfour-Browne (1994).

In this paper we describe the new species, reportnew locality records for five known species, andinclude illustrations of the male genitalia in bothlateral and ventral views for the 14 species ofOrchymontia now known to live in New Zealand.Also, we propose three species groups (with one ofthem subdivided into three subgroups) within thegenus Orchymontia, mainly based on the morphology of the male genitalia and supported byfeatures of the male middle tibiae.Abbreviations used for repository institutions are as follows:

CUMS - Departamento de Biología Animal,Universidad de Murcia, Murcia, Spain.

JNNZ - John Nunn Collection, Dunedin,New Zealand.

MONZ - Museum of New Zealand Te PapaTongarewa,Wellington, New Zealand.

NZAC - New Zealand Arthropod Collection,Landcare Research N.Z. Limited, Auckland,New Zealand.

Two letter abbreviations indicating collectingareas are those proposed by Crosby et al. (1976).

SystematicsGenus Orchymontia Broun, 1919

Ordish (1984) regarded nine species ofOrchymontia as forming a natural species groupbased on the presence of a distally membranousmedian lobe in the male genitalia. Of the remain-ing four species, he stated that O. bidentata and O. latispina seemed to be closely allied to eachother, while O. curvipes and O. crassifemur had widelydivergent male genitalia.

We have made a comparative study of the genitalia and of some external features from malesof all the species of Orchymontia. We found that certain morphological patterns have emerged,especially in the shape and chaetotaxy of the aedeagus and, to a lesser degree, in the shape of themiddle tibiae.Thus, we propose a new arrange-ment of the 14 species which differs somewhatfrom that of Ordish (1984).We recognise threespecies groups: the spinipennis (11 species, further

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subdivided into three subgroups), the curvipes (twospecies), and the crassifemur (a single species) groups.

spinipennis species groupThis group comprises 11 species in which the

main piece (combined basal piece and median lobe)of the aedeagus is broad in ventral view and has awell developed, apical translucent membrane whichis usually expanded (Figs 1, 3, 5, 7, 9, 11, 17, 19,21, 25, 27).The setae of the two separate groupssituated on the ventral side of the main piece are ofthe same length or slightly different. The parameresare slender with rows of setae only on their distalends.This group can be further subdivided into the spinipennis (6 species), the calcarata (3 species) and the bidentata (2 species) sub-groups.spinipennis s u b gr o u p

Formed by the following six species:O. banksiana, O. ciliata, O. dilatata, O. spinipennis,O. otagensis and O. vulgaris. In these species, the mainpiece of the aedeagus is sinuate in ventral view witha width about 1/5 of its length, and the translucentmembrane is rounded (Figs 1, 3, 5, 7, 9, 11).The two groups of setae on the main piece are relatively close to each other, with the proximalgroup situated about the midline in ventral view.The male middle tibiae have a well developed spurpointing backwards (see Figs 67, 70, 73, 77, 78, 79in Ordish, 1984).

Orchymontia banksiana Ordish, 1984Figs 1, 2

Orchymontia banksiana Ordish, 1984: 24, Figs 15, 39, 67, 94,123.

M aterial examinedPa r atypes: 5 , 5 , Kaituna Stream, Banks

Peninsula (MC), 20 March 1973, G. Kuschel(MONZ, in alcohol).

Orchymontia ciliata Ordish, 1984 Figs 5, 6

Orchymontia ciliata Ordish, 1984: 25, Figs 42, 70, 97.M aterial examined

Pa r atype: 1 ,Waitaiki Stream, Karioi,Taihape(RI), 6 January 1961, B.A. Holloway (MONZ, drymounted).

New records: 1 , 3 , Catchpool Stream,Rimutaka (WN), 28 December 1992, J. Nunn;9 , 4 , Pauatahanui Stream, Moonshine Road,

Judgeford (WN), 29 December 1992, J. Nunn; 1 ,Pakurataki Forks,Wellington (WN), 6 January1993, J. Nunn; 1 , Karori Reservoir,Wellington(WN), 1 December 1996, J. Nunn; 1 , RimutakaStream at bridge no. 4 (on State Highway 2,Wellington - Featherston) (WA), 17 November1996, J.A. Delgado & M. Martinez-Esparza; 1 , inunnamed stream flowing through WaiorongomaiStation into the western side of Lake Wairarapa(WA), 17 November 1996, J.A. Delgado & M. Martinez- Esparza; 1 , same locality, 2 January1997, J.A. Delgado, M. Martinez-Esparza & R.L.Palma (MONZ, CUMS, JNNZ, dry mounted).

Orchymontia dilatata Ordish, 1984Figs 7, 8

Orchymontia dilatata Ordish, 1984: 26, Figs: 45, 73, 124.M aterial examined

Pa r atypes: 1 , Dinner Creek, Lake Hawea(OL), 29 March 1973, G. Kuschel (MONZ, drymounted); 6 , 10 , Black Birch Stream,Hooker Valley, McKenzie Basin (MK), 2 April 1977,J.S. Dugdale (MONZ, in alcohol).

Orchymontia spinipennis Broun, 1919Figs 3, 4

Orchymontia spinipennis Broun, 1919: 108.Hydraenodes spinipennis Broun, 1921: 479.Orchymontia spinipes Orchymont, 1937: 155.Orchymontia spinicollis Jeannel, 1940: 130.Orchymontia spinipennis; Ordish, 1984: 28, Figs 8, 22, 50, 78,102, 125.

M aterial examinedSpecimens recorded by Ordish (1984): 2 ,2 , Lake Thompson Hut,Te Anau, FiordlandNational Park (FD), 4 December 1973,D.A. Craig; 1 , 1 , Hawk Range Station (KA),12 April 1973, G. Kuschel & J. McBurney; 1 ,Hanmer River, Hanmer Springs (MB), 15 June1984, R.L.C. Pilgrim; (all samples MONZ, in alco-hol).

New records: 4 , 5 , Dog Stream,Hanmer Springs (MB), 19 December 1995, J.Nunn; 2 , 1 , Ote Makura Stream, Goose Bay(KA), 13 January 1994, J. Nunn (MONZ, CUMS,JNNZ, dry mounted).

Orchymontia otagensis Ordish, 1984Figs 9, 10

Orchymontia otagensis Ordish, 1984: 28, Figs 49, 77.

New Zealand Entomologist, vol 22, March 2000.

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Delgado & Palma: Taxonomic review of Orchymontia (Coleoptera: Hydraenidae)

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Figs 1-8: Male genitalia. Orchymontia banksiana (Paratype,Banks Peninsula) 1, ventral view; 2, right lateral view. O.spinipennis (Dog stream) 3, ventral view; 4, right lateral view.O. ciliata (Pakurataki Forks) 5, ventral view; 6, right lateral

view. O. dilatata (Paratype, Lake Hawea) 7, ventral view; 8,right lateral view. Scale: 0.1 mm.The left paramere has beenomitted in all lateral views.

1 2 3 4

5 6 7 8


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9 10 11 12

13 14 15 16

Figs 9-16. Male genitalia. Orchymontia otagensis (Leith).9, ventral view; 10, right lateral view. O. vulgaris (Rai River)11, ventral view; 12, right lateral view. O. curvipes (Holotype)13, ventral view; 14, right lateral view. O. dugdalei (Karori

Reservoir) 15, ventral view; 16, right lateral view.Scale: 0.1 mm.The left paramere has been omitted in all lateral views.

M aterial examinedPa r atypes: 1 , 1 , Carey Creek, Evansdale

(DN), 2 March 1973, G. Kuschel (MONZ, in alcohol); 2 , Skippers Road, Coronet Peak,(OL), 25 March 1973, G. Kuschel (MONZ, drymounted).

New records: 1 ,Waipori Falls,Waipori River(DN), 22 January 1994, J. Nunn; 2 , 2 , waterof Leith, Leith Valley (DN), 25 January 1994,J. Nunn (MONZ, CUMS, JNNZ , dry mounted).

Orchymontia vulgaris Ordish, 1984Figs 11, 12

Orchymontia vulgaris Ordish, 1984: 29, Figs 51, 79, 103.M aterial examined

Pa r atypes: 7 , 27 , Pukaka stream,Tuamarina, Marlborough (MB), 25 May 1975,R.G. Ordish; 22 , 19 ,Waitohi River (MB),25 May 1975, R.G. Ordish (MONZ, in alcohol).

New records: 1 , 3 ,Tapu Stream,Tapu(CL), 22 November 1995, J. Nunn; 3 , 2 ,Rai River, near Pelorus Bridge (MB),30 November 1996, J.A. Delgado & M. Martinez-Esparza; 1 , 1 , Norris Creek near GoldenDowns (NN), 1 December 1996, J.A. Delgado,J.S. Dugdale & M. Martinez-Esparza; 1 , Mai MaiCreek, Mahitahi (WD), 5 December 1996,J.A. Delgado & M. Martinez-Esparza (MONZ,CUMS, JNNZ, dry mounted).Remarks

Our new records of O. vulgaris extend the knowngeographical distribution of this species to the dis-tricts of Coromandel (CL) in the North Island andWestland (WD) in the South Island.

calcara ta s u b gr o u pThis subgroup comprises three species:

O. calcarata, O. laminifera and O. latispina. In thesespecies, the main piece of the aedeagus is broaderthan those in the spinipennis subgroup, with awidth about 1/4 of its length in ventral view, andthe translucent membrane is not rounded, havingat least one marginal angle (Figs 17, 19, 21).The two groups of setae on the main piece aremore separated from each other, with the proximal group situated towards the right side.The male middle tibiae have a well developed spurpointing at right angles to the longitudinal axes ofthe tibiae (see Figs 69, 75, 76 in Ordish, 1984).

Orchymontia calcarata Ordish, 1984Figs 17, 18

Orchymontia calcarata Ordish, 1984: 25, Figs 41, 69.M aterial examined

Pa r atypes: 1 , 1 , Dinner Creek, Lake Hawea(OL), 29 March 1973, G. Kuschel (MONZ, inalcohol); 1 , Simonin Pass, Olivine Range (WD),30 January 1975, J.S. Dugdale (MONZ, drymounted).

Orchymontia laminifera Ordish, 1984Figs 19, 20

Orchymontia laminifera Ordish, 1984: 27, Figs 47, 75.M aterial examined

Pa r atype: 1 , Simonin Pass, Olivine Range(WD), 30 January 1975, J.S. Dugdale (MONZ, inalcohol).

Orchymontia latispina Ordish, 1984Figs 21, 22

Orchymontia latispina Ordish, 1984: 27, Figs 48, 76,100, 101.

M aterial examinedPa r atypes: 2 , Moonstone Lake (NN),

7 February 1973, A.K.Walker (MONZ, drymounted); 4 , 5 , Surveyors Creek, KarameaBluff (NN), 25 June 1973, G. Kuschel & J.M. McBurney (MONZ, in alcohol).

bidentata s u b gr o u pThis subgroup comprises two species: O. bidentata

and O. nunni new species. In these species, the mainpiece of the aedeagus is broader than any other inthe genus, with a width about 1/3 of the length inventral view (Figs 25, 27).The translucent membrane is less expanded and the two groups ofsetae on the main piece are situated closer to theleft side.The male middle tibiae have a small spurover a rounded keel (Figs 29, 30).

Orchymontia bidentata Ordish, 1984Figs 27, 28, 30

Orchymontia bidentata Ordish, 1984: 24, Figs 4, 40, 68,95, 96.

M aterial examinedPa r atypes: 1 , Mangapohue Stream,Waitomo,

13 March 1975, G. Kuschel (MONZ, dry mounted); 1 , 1 , small stream near LakeWaikaremoana (GB), 19 November 1975,G. Kuschel (MONZ, in alcohol).


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17 18 19 20

21 22 23 24

Figs 17-24: Male genitalia. Orchymontia calcarata (Paratype,Simonin Pass) 17, ventral view;18, right lateral view.O. laminifera (Paratype, Simonin Pass) 19, ventral view; 20,right lateral view. O. latispina (paratype, Moonstone Lake) 21,

ventral view; 22, right lateral view.O. crassifemur (Paratype, Lake Cobb) 23, ventral view; 24, rightlateral view. Scale: 0.1 mm.The left paramere has been omitted in all lateral views.


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Orchymontia nunni n. sp.Figs 25, 26, 29

M aterial examinedHolotype (dry mounted): 1 , Karori

Reservoir,Wellington (WN), New Zealand,20 November 1996, J. Nunn (MONZ).

Pa r atypes (all dry mounted): 3 , same dataas holotype; 1 , 2 , same locality and date asholotype, J.A. Delgado; 1 , same locality,19 February 1995, J. Nunn; 1 , same locality,20 February 1995, J. Nunn; 1 , same locality,22 November 1996, J. Nunn; 1 , same locality,1 December 1996, J. Nunn; 2 , same locality,7 December 1996, J. Nunn (MONZ, NZAC,CUMS, JNNZ).Descript ion

Length: 2.50 mm; width: 0.86 mm.Colour: Uniformly dark reddish-brown, with

paler humeral areas.Head: Smooth, shiny and sparsely pubescent.

Male maxillary palps with penultimate segmentnot enlarged and without a ventral groove.Thorax: Pronotum 1.2x as wide as long, finelypubescent; lateral margins slightly crenulate anteriorly. Elytra 1.8x as long as wide, broadlyrounded, with wide margins; discal punctures onstriae obsolete; humeral spines obsolete.Hind wings generally reduced but fully developedin two specimens.

Legs of male: middle trochanters without asmall tooth on distal margin; middle femora notenlarged; middle tibiae (Fig. 29) straight, with ansmall spur over a smoothly rounded keel; hind tibiae with a few long, distal, ventral setae andsome short spines.

Male genitalia (Figs 25, 26): Main piece ofaedeagus massive, with a distinct emarginationbetween the two groups of setae in ventral view(Fig. 25). The distal end of the main piece has aconical process tapering to a fine point on theright side (Fig. 26), and a partially developedtranslucent membrane on the left side.Remarks

Orchymontia nunni is morphologically closest toO. bidentata. They are of similar size, colour andhabitus; therefore it is very difficult to distinguishthe females of these two species. Externally, malesof O. nunni can be distinguished by the shape oftheir middle tibiae, which are less curved than inO. bidentata, and by the shape of the keel on the

inner side of the middle tibiae (Figs 29, 30). Also,the penultimate segment of the male maxillarypalps differs between O. nunni and O. bidentata,being weakly grooved and slightly enlarged in thelatter species. Notwithstanding the similaritybetween O. nunni and O. bidentata, if Ordish’s(1984) key is used, males of O. nunni will key to O.otagensis because their maxillary palps are notexpanded or grooved ventrally. Females of O.nunni, on the other hand, will key to O. bidentata.

The male genitalia (Figs 25 - 28) exhibit the bestfeatures to separate O. nunni from O. bidentata andfrom all other species in the genus.The main pieceof the aedeagus in O. nunni is the broadest of allspecies in both ventral and lateral views (Figs 25,26). Further, in ventral view, O. nunni has an emargination between the two groups of setae (Fig. 25) which is absent in O. bidentata (Fig. 27),and the distal end of the right process is sharplypointed in O. nunni but is blunt in O. bidentata.Geogr aphical distri but ion

Only known from the type locality.Etymology

This species is named after our colleague Mr John Nunn, the collector of most of the typematerial and one of the best collectors of New Zealand beetles.

curvipes species gr o u pThis group comprises two species, O. curvipes and

O. dugdalei. They have an aedeagus with a mainpiece slender in ventral view (Figs 13, 15), andmarkedly curved in lateral view (Figs 14, 16).The apical translucent membrane is reduced.The setae of the proximal group on the main pieceare very long, about 6 -7 times longer than thosein the distal group (Figs 13 - 16).The parameresare slender with rows of setae only on their distalends.The male middle tibiae have weakly roundedexpansions, without a spur (see Figs 72, 74 inOrdish, 1984).

Orchymontia curvipes Ordish, 1984Figs 13, 14

Orchymontia curvipes Ordish, 1984: 26, Figs 44, 72 and 99M aterial examined

Holotype: 1 , Lake Hutt, University CampStream (MC), 10 December 1973, G. Kuschel(NZAC, dry mounted).

Pa r atypes: 1 , 5 , same data as holotype,(MONZ, in alcohol); 1 , 1 , same data, (NZAC,


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25 26

27 28

Figs 25-28: Male genitalia. Orchymontia nunni (Holotype) 25, ventral view; 26, right lateral view. O. bidentata (Paratype,

Waitomo) 27, ventral view; 28, right lateral view. Scale: 0.1mm.The left paramere has been omitted in all lateral views.

dry mounted); 3 , 1 , Dinner Creek, LakeHawea (OL), 29 March 1973, G. Kuschel(MONZ; NZAC, dry mounted).

Orchymontia dugdalei Ordish, 1984Figs 15, 16

Orchymontia dugdalei Ordish, 1984: 27, Figs 46, 74.M aterial examined

Holotype: 1 , Kohukohunui, Hunua (AK),30 March 1974, J.S. Dugdale (NZAC,dry mounted).

Pa r atypes: 1 , 1 , same data (NZAC, drymounted).

New records: 2 , 2 , Karori Reservoir,Wellington (WN), 30 November 1996,J. Nunn; 1 , 1 , same locality, 1 December 1996,J. Nunn (MONZ, CUMS, JNNZ, dry mounted).

RemarksOur new records of O. dugdalei in the southern

end of the North Island considerably expand theknown geographical distribution of this species,hitherto known from the Auckland region only(Ordish, 1984).

crassifemur species gr o u pThis group comprises a single species with

unique genitalia within the genus.The main pieceis strongly keeled, distally diverging and withoutsetae (Figs 23, 24).The parameres are broad, eachwith a row of setae situated approximately on theirmidpoint, in addition to those on the distal end(Fig. 23).The distal half of the male middle tibiaeis very broad (see Fig. 71 in Ordish, 1984).

Orchymontia crassifemur Ordish, 1984(Figs 23, 24)

Orchymontia crassifemur Ordish, 1984: 25, Figs 43, 71, 98.M aterial examined

Pa r atypes: 1 , Lake Cobb (NN), 9 February1973, G. Kuschel (MONZ, dry mounted); 1 ,Swamp Stream, Lewis Pass (BR), 11 April 1973,G. Kuschel (MONZ, in alcohol).

AcknowledgementsWe are indebted to Prof. Robert L. C. Pilgrim

and Mr John S. Dugdale for their hospitality andvaluable assistance towards our fieldwork, and toMr Ron Ordish for sharing his vast knowledge ofhydraenids with us. Also to Ms María Martínez-Esparza for her important contribution and companionship during our collecting in the field.We are grateful to the authorities of the KaroriReservoir Wildlife Sanctuary Trust (Inc.) for allowing us to collect in the Reservoir area; to Dr Trevor K. Crosby for making available specimens under his care; and to Mr Philip J.Sirvid for his critical review of the manuscript.Our special thanks go to Mr John Nunn who notonly collected most of the material of O. nunni, butalso made available to us all his other specimens ofOrchymontia and shared with us his detailed knowl-edge of the Karori Reservoir.

ReferencesBroun T. 1919. A new genus of Hydraenidae from

New Zealand. Annales de la Société Entomologique deBelgique 59: 108-109.

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29 30

Figs 29-30: Male right middle tibiae.29, Orchymontia nunni. 30, O. bidentata. Scale: 0.1 mm.


Broun T. 1921. Descriptions of new genera andspecies of Coleoptera. Bulletin of the New ZealandInstitute 1(6): 475-590.

Crosby TK, Dugdale JS,Watt JC. 1976. Recordingspecimen localities in New Zealand: an arbitrary system of areas and codes defined. New ZealandJournal of Zoology 3(1): 69 + map.

Hansen M. 1991. A review of the genera of the beetle family Hydraenidae (Coleoptera). Steenstrupia17(1): 1-52.

Jäch M. 1993 Taxonomic revision of the Palearcticspecies of the genus Limnebius Leach, 1815(Coleoptera, Hydraenidae). KoleopterologischeRundschau 63: 99-187.

Jäch M. 1995. Taxonomic synopsis of the genusLaeliaena, Sahlberg, 1900 (Coleoptera: Hydraenidae).Elytron 8: 35-41.

Jeannel R. 1940. Croisiere du Bouganinville aux îlesaustrales françaises. III. Coléopteres. Mémoires duMuséum National d Histoire Naturelle de Paris (n.s.) 14:63-201.

Orchymont A. 1937. Check list of the Palpicornia ofOceania (Coleoptera, Polyphaga). Occasional Papers ofBernice P. Bishop Museum 13(13): 147-160.

Ordish, RG. 1984. Hydraenidae (Insecta:Coleoptera). Fauna of New Zealand No. 6, 56 pp.

Perkins PD. 1980. Aquatic beetles of the familyHydraenidae in the western hemisphere:Classification, biogeography and inferred phylogeny(Insecta: Coleoptera). Quaestiones Entomologicae16(1,2): 1-554.

Perkins PD. 1997. Life on the effective bubble:Exocrine secretion delivery systems (ESDS) and theevolution and classification of beetles in the familyHydraenidae (Insecta: Coleoptera). Annals of CarnegieMuseum 66(2): 89-207.

Perkins PD, Balfour-Browne J. 1994.A contribution to the taxonomy of aquatic and humicolous beetles of the family Hydraenidae inSouthern Africa. Fieldiana: Zoology, New Series No. 77, i-viii + 159 pp.


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Taxonomic review of the genus Orchymontia (Coleoptera: Hydraenidae)

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