A Critical Analysis of A.V. Martynov’s Version of Ontogenetic Systematics

A CRITICAL ANALySIS oF A.V. MARTyNoV’S VERSIoNoF oNTogENETIC SySTEMATICS

Zoological museum, moscow lomonosov state University,bolshaya nikitskaya str. 6, moscow 125009, russia

[email protected]

Thalassas, 29(2) · June 2013: 23-33An International Journal of Marine Sciences

Key words: ontogenetic systematics, developmental systematics, evolutionary models, taxon, taxonomic diagnosis, tree thinking, cycle thinking,

ontogenetic cycle.

Palabras clave: Sistemática ontogenética, sistemática del desarrollo, modelos evolutivos, taxón, diagnosis taxonómica, sistemática filogenética,

concepción sistemática, ciclo ontogenético.

igor ya. Pavlinov

23Thalassas, 29(2) · June 2013

ABSTRACT

Ontogenetic systematics is based on the general idea that the arrangement of taxa within a classification should reflect diver-sity of developmental (ontogenetic) patterns peculiar to organisms allocated to these taxa. As understood here, it includes such taxonomic approaches as Nelson—Platnick’s pattern cladistics and Ho’s version of rational taxonomy. One of its most recent conceptions is the one elaborated by A. Martynov (2009–2011), central for which is a notion of ontogenetic cycle, and the entire conception is defined by its author as a theory of “formation and decay of the ontogenetic cycles”. The latter con-ception is shown to be inconsistent as an artificial combination of mutually incompatible principles borrowed from different taxonomic schools (phenetics, typology, cladistics).

RESUMEN

La sistemática ontogenética se basa en la idea general de que la disposición de los taxones dentro de una clasificación debe reflejar la diversidad de patrones de desarrollo (ontogenético) propios de los organismos adjudicados a estos taxones. Tal como se entiende aquí, incluye enfoques taxonómicos tales como el modelo cladístico de Nelson-Platnick y la versión Ho de la taxonomía racional. Una de las concepciones más recientes es la elaborada por A. Martínov (2009-2011), para la que resulta básico el concepto de ciclo ontogenético, y todo el modelo es definido por su autor como una teoría de la “formación y la descomposición de los ciclos ontogenéticos”. Esta última concepción se muestra aquí como inconsistente, al ser una combi-nación artificial de principios mutuamente incompatibles tomados prestados de diferentes escuelas taxonómicas (feneticismo, tipología, cladística).

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INTRODUCTION

Conceptions in contemporary systematics are rather diverse, notwithstanding that they are usually delimited by but few predominating schools, namely cladistics, evolutionary taxonomy and numerical phenetics (Hull, 1970; Ereshefsky, 2008). Due to such an attitude, some noteworthy contemporary schools escape attention of the theoreticians; these are biosystematics (Lines, Mertens, 1970; Stace, 1989; Feliner, Fernandez, 2000), rational taxonomy (Ho, 1992; Ho, Saunders, 1993; Webster, Goodwin, 1996), and ecomorphological approach (Aleev, 1986; Leontiev, Akulov, 2004; Pavlinov, 2010); for their most recent complete review, see Pavlinov, Lyubarsky (2011). Such a “minimizing” position in consideration of the current taxonomic schools impoverishes significantly the entire diversity of theoretical thoughts in systematic biology and provides a biased estimate of both its present state and possible future pathways.

Among these schools nearly “forgotten” by the scholars reviewing contemporary “systematic philosophies”, there is one which can be, by and large, called ontogenetic systematics. The latter word-combination intends to emphasize principal idea of this taxonomic doctrine, according to which the arrangement of taxa within a classification should reflect diversity of developmental (ontogenetic) patterns peculiar to organisms allocated to these taxa. As a matter of fact, it is rarely mentioned in contemporary literature and, even if accounted, then under different designations, such as “developmental systematics” (Orton, 1955; Babbitt, 2005), “ontogenetic systematics” (Albert et al., 1998; Martynov, 2009a,b; 2011a,b) or occasionally as a part of the rational taxonomy (Ho, 1990, 1992; Ho, Saunders, 1993). Paradoxically enough, the pattern cladistics, which bases all its taxonomic decisions on analyses of just the ontogenetic patterns (Nelson, 1974, 1989; Platnick, 1982; Patterson, 1983), was never mentioned in this context. Meanwhile, ontogenetic systematics, in its extended understanding adopted here, has quite a profound biological content, unlike, for instance, the molecular taxonomy with its reducing background.

The ontogenetic systematics is reviewed briefly in the present paper, with a special attention paid to its version elaborated recently by A. Martynov (2009–2011), as one of his papers was published just in the Thalassas.

Ontogenetic systematics: its brief history and current versions

Very schematically, the general idea of ontogenetic systematics, as it is now called and understood, ascends

to K. von Baer who has been the first to interpret taxa of the Natural System (in particular, enbrаnchements of G. Cuvier’s “Animal Kingdoms”) as reflecting generalized ontogenetic patterns of organisms embraced by them (Gould, 1977). Subsequently, with E. Haeckel having come with his “Systematische Phylogenie”, von Baerian approach gained phylogenetic interpretation and took one of the leading positions in systematics of the late 19th to the early 20th centuries. As a matter of fact, most of the phyla of multicellulate animals were recognized at that time based mostly on analysis of their development (for a review, see Dogel, 1975). In a wider perspective, inclusion of ontogenetic criteria in at least some theoretical definitions of homology and in respective recognition of particular homologies (Goodwin, 1994) make most of both earlier and more recent morphology-based systematics also ontogeny-based, in a sense (Kluge, Srauss, 1985).

It so happened that a strong trend toward adoption of reducing approaches in systematic biology since the first third of the 20th century led to forcing basically holistic ontogenetic systematics (as it is understood here) out of its leading position. The first has been population systematics and the next was phenetics, both focused on lower levels of taxonomic hierarchy, at which no ontogenetic variability is significantly expressed in most cases. Then came cladistics addressed to higher levels of that hierarchy, but with its peculiar concept of semaphoront (Hennig, 1966) imposing an obvious strong restriction on analyses of the entire ontogenetic patterns and thus making it clearly “anti-ontogenetic” in its background (Martynov, 2011a). And at last molecular phylogenetics appeared with its raw data not permitting to deal with ontogeny at all (Patterson, 1983). All this, as mentioned above, led to a decline in interest to the ontogenetic systematics (but see Conclusions below about Evo—Devo).

It was, however, in the mid 20th century when the general idea under consideration was first proclaimed and nominated “officially” by ichthyologist G. Orton (1955) as a “developmental systematics”, according to which “judgment in taxonomy and evolution should be based on a unified summary of the data obtainable from the entire developmental pattern” (op. cit., p. 76). This Orton’s appeal was at least once applied subsequently in systematics of a particular arthropod group (Babbitt, 2005).

Belonging to ontogenetic systematics, in the above extended sense, seems to be pattern cladistics having emerged within a framework of the Hennigian phylogenetic systematics (Nelson, 1974, 1989; Platnick, 1982). My allocation of this taxomomic school to the ontogenetic systematics is based on declaration of its

24 Thalassas, 29(2) · June 2013

a criTical analySiS OF a.V. MarTynOV’S VerSiOn OF OnTOgeneTic SySTeMaTicS

proponents that hierarchy of taxa in a classification should be inferred from the hierarchy of ontogenetic patterns. So this is actually and explicitly an ontogeny-based approach.

A concept similar, at the level of general idea, to that of Orton and Nelson—Platnick was developed by M.-W. Ho not so far ago as a part of the rational taxonomy (Ho, 1990, 1992; Ho, Saunders, 1993). In this case, the focal point is the ordered processes of ontogenetic transformations, from which decisions about taxonomic arrangements can be inferred.

A term used here to designate this doctrine (“ontogenetic” rather then “developmental”) was coined more recently, though without explicit definition and with a somewhat different meaning (Albert et al., 1998). These authors meant under their “ontogenetic systematics” an issue of tracing morphogenetic (including molecular) mechanisms of origin of diversity of an adult structure (petals in their particular case) in different taxa thus evidently relating their approach to Evo—Devo (mentioned in Stuessy, 2008; De Craene, 2010).

At last, a most recent attempt to regain the former prestigious position of ontogenetic systematics was undertaken by invertebrate zoologist A. Martynov (2009a,b; 2011a,b), who developed his own version of this general approach independently of those mentioned above based on his ideas of relation between taxonomy, phylogeny and ontogeny (see below).

As it is obvious from the above, ontogenetic (=developmental) systematics, as it is understood here, is quite heterogeneous in its sources and theoretical backgrounds. As a matter of fact, it is considered here in such a widened treatment for the first time. Meanwhile, its uniting idea seems to be quite clear and straightforward: all judgements about content, boundaries and systematic position of the taxa within a classification should be deduced, some or other way, from ontogenetic observations and/or experiments. So, any concept, which follows this general argumentation scheme, deserves being allocated here, whatever might be its original context.

The attention paid herewith to the Martynov’s version of ontogenetic systematics is explained by the following. On the one hand, it is the most recent concept, which is most actively popularized by its author as a sole representative of the school under consideration. From the other hand, many of Martynov’s ideas, which are suggested by him as a core of ontogenetic systematics, I consider incorrect and inconsistent. Therefore, it seems

quite timely to provide a critical analysis of his conception within a more wide theoretical framework in order to show its proper place within ontogenetic systematics. As the version in question is not especially familiar to taxonomists, I start my analysis with its brief outlining.

Basics of Martynov’s ontogenetic systematics

The central claim of the entire conception in question is formulated by its author as a theory of “formation and decay of the ontogenetic cycles” (Martynov, 2011a, p. 135). By this, Martynov goes back to that phase in the history of taxonomy in the first half of the 20th century, when population (bio)systematics emerged to substitute the “old-fashioned” traditional typological (and occasionally phylogenetic) systematics by a “new” biological one (Pavlinov, Lyubarsky, 2011). Proponents of this taxonomic school became the first to appeal to consider systematics as a science not of taxa but of their emergence in the course of Darwinian evolution (Huxley, 1940). Such initial proposition predestines all other more particular concepts that constitute the core of Martynov’s version of ontogenetic systematics.

Presentation of the entire body of this version starts with a “main hierarchical principle” introduced as no less than the core of the taxonomic theory (Martynov, 2011a, p. 35). That is, it is this empirical fact of hierarchical arrangement of taxonomic classifications that is suggested to be the main theoretical generalization for the entire systematic biology. With this, Martynov really believes that it is the classical systematics (the school of Linnaeus and his fellows) that had elaborated it (Martynov, 2009а, 2011a). He concludes from this that taxonomic hierarchy has not a logical but basically a biological (natural) background. By this, he shelves a fundamental question underlying taxonomic hierarchy; to what extent it reflects the hierarchical arrangement of nature and to what extent it is a consequence of hierarchical classificatory algorithm (Hawksworth, Bisby, 1988; Ereshefsky, 2001; Pavlinov, 2007a).

Paradoxically enough, Martynov blames contemporary phylogenetics for its “underestimating” the hierarchical principle, with emphasizing that cladistics was never “even aware” of it. With this, he believes that rejection of paraphyletic groups by cladists means their “challenging” the above hierarchical principle. However, quite the contrary, it is the cladistic ranking principle of sister groups categorical equality that brings the above “hierarchical principle” to its logical perfection (Hennig, 1966; Wiley, 1981; Wägele, 2005). And it is the contemporary phylogenetics that is seriously preoccupied with the justification of taxonomic hierarchy by referring


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to phylogenetic pattern resulting from divergent phylogeny (Eldredge, Cracraft, 1980; Wiley, 1981; Pavlinov, 2005; Wägele, 2005).

Pattern cladistics also pays much attention to substantiating taxonomic hierarchy, though not from phylogenetic, like the hennigians, but rather from a pure ontogenetic standpoint (Nelson, 1974, 1989; Platnick, 1982; Patterson, 1983). By the latter, pattern cladistics seems to look much more “ontogenetic” than Martynov’s approach, in which taxonomic hierarchy is established on a combinatorial basis without recruiting any ontogenetic reasoning (see the next section). Curiously enough, Martynov does not mention the ideas of this cladistic school in his publications.

The working principles of Martynov’s ontogenetic systematics are summarized in the list of 12 points, of which only a minority (three or four) are relevant directly to the taxonomy in its strict sense, while the remainders concern ontogenetic evolution (Martynov, 2009a, 2011a,b). The taxonomic principles proper, besides the above central claim, can be summarized as follows (listed accordingly to their theoretic significance): (a) a unit of ontogenetic systematics is the ontogenetic cycle; (b) taxon is respectively defined as such an ontogenetic cycle; (c) the entire taxonomic hierarchy is represented as a tree-like scheme of transformations of those cycles, (d) taxa are primarily recognized by combinations of morphological traits and then generalized ancestral ontogenetic patterns are inferred for them; (e) diagnoses of these taxa include “models” of respective ontogenetic patterns. These points are considered more closely in subsequent sections.

Classification, phylogeny, ontogeny

The logical relations between evolutionary and taxonomic judgements was and remains (and will certainly persist) one of the most fundamental and most disputable issues of the entire systematic biology since Darwinian—Haeckelian revolution. There are two opposite standpoints in answering it, each with its own philosophical background. According to one of them, which is historically primary, classification precedes its evolutionary interpretation, with the latter appearing to be secondary relative to the former. This is characteristic for typological and more recent phenetic taxonomic schools; classical (Haeckelian) phylogenetics also follows this argumentation scheme and is therefore referred to sometimes as a kind of phylogenetic typology, or “pseudo-phylogenetics” (Remane, 1956; Levit, Meister, 2006). The opposite is the scheme according to which classification should be based on some prior evolutionary

scenarios (Hennig, 1966; Wiley, 1981); this is now acknowledged as one of the most characteristic features of the Hennigian cladistics, which makes this school of systematics actually evolutionary, that is based on evolution and not preceding it (de Queiroz, 1988; de Queiroz, Gauthier, 1992). In terms of the above logical relations, the first approach can be called, with certain reservations, “deductive” — phylogeny is deduced, i.e. inferred from a priory obtained classification, while the second is respectively “inductive” — classification is inferred a posteriori from phylogeny (Pavlinov, 2011a).

Ontogenetic systematics adds a third component to this problematic issue, namely the ontogenetic judgements. With the phylogenetic inferences remaining in effect, this provides eventually a three-partitioned argumentation scheme, in which the above relation between phylogeny and classification is supplemented with two more, viz. relations between ontogeny and classification, on the one hand, and between ontogeny and phylogeny, on the other hand. All this makes the entire line of reasoning in ontogenetic systematics most sophisticated among taxonomic paradigms. Its particular elaboration by each of the above versions of this school results in several argumentation schemes, which can roughly be packed up into above “deductive” and “inductive” methodologies as follows. In this particular case, “deductive” means that ontogenetic reconstructions is inferred from a priory obtained classification, while “inductive” means that it is the classification that is a posteriori inferred from ontogenetic reconstructions.

The approach proclaimed by Ho (1990, 1992) is evidently “inductive” in both phylogenetic and ontogenetic respects. Ho’s algorithm presumes the following steps: (a) analysis of ontogenetic patterns in a particular group of organisms, (b) representation of diversity of these patterns in a form of branching “ontogenetic tree”, (c) the latter’s treatment, under some provisions, as a phylogenetic tree, (d) representation of this tree in a form of classification, with its branches being treated as taxa. As it is seen, in this approach a classification is a posteriori derived from phylogenetically interpreted “ontogenetic tree”.

The approach elaborated by pattern cladistics is “inductive” with respect to the relation between ontogeny and classification, while it is “deductive” with respect to the relation between phylogeny and classification. In this case, diversity of ontogenetic patterns is first studied, from which a hierarchy of so called “defining characters” is inferred, which serves directly as a basis for constructing the respective taxonomic hierarchy. As to the phylogenetic hypothesis, it is deduced from taxonomic hierarchy by its representation in a form of branching



cladogram following some formal rules (Nelson, 1974, 1989; Platnick, 1982; Patterson, 1983).

Martynov’s scheme is evidently “deductive” in both of the above respects. He starts with a claim that “procedures of classical taxonomy (and the entire hierarchy discovered earlier) rather precede the implementation of a “phylogenetic” analysis, but are not resulted from it” (Martynov, 2011a, p. 34, italics original). Accordingly, the following analytic procedure is implied. A classification is first derived for a group studied based on combinatorial analysis of supposedly homologous traits, with particular taxa being recognized by respective unique combinations of these traits. Afterwards, generalized ontogenetic patterns are reconstructed for these taxa, with subsequent interpretation of these patterns as ancestral (or basic, after Orton) for the respective taxa. Then, hierarchy of all these patterns is represented in a tree-like manner, with the latter being probably equivalent to what Ho (1990) calls “ontogenetic tree”. After that, initial classification is suggested to treat as a “reconstructed system of the ancestral ontogenetic cycles” (Martynov, 2011, p. 139). And, at last, the tree inferred from initially elaborated classification is interpreted as a representation of evolutionary scenario of ontogenetic patterns in the group studied. So, within this conception, it looks like particular classifications are initially designed to serve as but a means for elaborating particular evolutionary scenarios of reconstructed ontogenetic cycles (patterns). Such a relation agrees with the above Martynov’s claim that his ontogenetic systematics is by and large about evolution of ontogenetic cycles and not about classifications themselves.

Secondary status of an inferred ontogenetic evolution relative to the classification in Martynov’s approach is emphasized by what he calls “presumption of the known cycle”. According to the latter, “with discovering of an unknown taxon, even differing significantly by its morphology from its most close relative forms, it is necessary to suppose that the former is but a previously unknown modification of the ancestral ontogenetic cycle of those forms” (Martynov, 2009a, p. 203). As no operational criteria for “being most close” are explicitly indicated, it just remains to suppose that similarity by combination of traits, by which the taxa have been distinguished initially, is presumed. This makes Martynov’s approach, among other things, very conservative with respect to possible rearrangements of any classifications in response to newly discovered ontogenetic patterns.

A posteriori phylogenetic interpretation of the classification and of the taxa with their reconstructed ancestral ontogenetic cycles is based on the following

taxonomic principles suggested by Martynov. According to them, each above-species taxon of whatever rank (a) has at its base a single ancestral species with its peculiar ontogenetic cycle, and (b) includes all subtaxa with their ontogenetic cycles derived from that ancestral cycle. It is evident, that these principles are nearly the same as those fundamental for Hennigian cladistics; they presume holophyletic status of taxa defined by “ontogenetic synapomorphies”.

Thus, Martynov’s version of ontogenetic systematics, with respect to the relations between taxonomic, phylogenetic and ontogenetic judgments, represents a curious eclectic combination of the principles borrowed (most probably unconsciously) from different taxonomic theories. Prior recognition of taxa by unique combinations of characters is phenetic. Generalized ancestral ontogenetic patterns reconstructed a posteriori for these taxa can most appropriately be treated as the latter’s archetypes. Finally, interpretation of taxonomic hierarchy based on “ontogenetic synapomorphies” is cladistic. By all this, the taxonomic conception under consideration can be characterized, in general, as a “cladistically interpreted phenetic typology”.

Taxon and ontogeny

One of the crucial points in any theoretically advanced taxonomic conceptions is that concerning proper definition of units of classifications. They are treated in most general sense as taxa, but their particular definitions may be quite different making them either phenons or cladons or typological continua or else. This issue involved such a fundamental question as the taxon ontology including relations between the taxon and the organisms belonging to it.

In analysis of the latter point, one of the most fundamental imperatives of contemporary natural science is to be accentuated first. According to it, there are entities of different ontology in nature, which are endowed with certain emergent properties and therefore cannot be thought about as “the same”, in a sense. In taxonomy, such entities which should not be mixed with each other are the taxon, as supra-organismal unit, and the organism (physical individual) proper.

As far as ontogenetic systematics is concerned, in its Ho’s version developed within rational taxonomy (see above) the taxon as a unit of classification should most appropriately be treated as the natural kind (in sense of Quine, I969) according to the general ontological consideration followed by rational taxonomy (Webster, Goodwin, 1996; Pavlinov, 2011b). Correspondingly, the

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individuals allocated to these taxa are considered as tokens of respective natural kinds (Brigandt, 2009). In a more empirical fashion, the taxon “can be defined as a class of individuals sharing a common developmental field” (Ho, 1992, p. 199). In the pattern cladistic version, this point was given no special attention.

As to the Martynov’s version, one of its focal points is a suggestion to treat the taxon as ontogenetic cycle; in its limiting formulation, it is the ontogenetic cycle that is suggested to be considered as a basic unit of classification and of systematics. Martynov calls this the “basic postulate” of his entire conception. The latter indicates that he by no means takes his treatments of “taxon as ontogenetic cycle” and “ontogenetic cycle as a unit of systematics” as something like a metaphor similar to, say, very popular metaphor of “phylogenetic tree” (which does not actually exist in nature). So, such a treatment of the taxon in Martynov’s ontogenetic systematic, in a somewhat simpler form sounding like “taxon as ontogeny”, should be taken quite literally. This means that, defining the taxon literally as the ontogenetic cycle (ontogeny), Martynov actually equates them, which is emphasized by the above Martynov’s declaration of the ontogenetic cycle as a unit of classification. By this, Martynov commits a serious mistake in mixing together two fundamentally different levels of generality of hierarchy of biological matter, supra-organismal (taxon) and organismal (physical individual in its strict sense).

Meanwhile, Martynov mentions elsewhere that the taxon is an assemblage of individuals (organisms), while ontogenetic cycle is an attribute of the individual (organism). Besides, he emphasizes not a once that, according to his conception, the ontogenetic cycle has nothing in common with the classical (Haeckelian) phylogenetic cycle. It is evident that this treatment of taxon is quite different from the previous one, and these two Martynov’s statements — taxon as an ontogenetic cycle (ontogeny) and taxon as an assemblage of individuals (ontogenies) — are mutually exclusive. Their combination in the same conception under consideration makes it intrinsically controversial.

Thinking styles in ontogenetic systematics

One of the central notions in contemporary cognitive science is that of cognitive (or thinking) style implying (or implied by) researchers’ way of perception of the world (Kholodnaya, 2004). Examples relevant to the systematics include, for instance, opposition of “typological vs. population” thinking styles, of “set vs. individual” treatments of taxonomic units, etc. In contemporary taxonomy based on the evolutionary idea, of crucial

importance is the so called “tree thinking” presuming perception of the diversity of life arranged not in an inclusive set hierarchy (stationary world) but rather in a phylogenetic tree (evolving world) (O’Hara, 1997; Pavlinov, 2007b).

Going back to the historical roots of ontogenetic systematics (see above), “organismal thinking” characteristic to German naturphilosophy of the 18th–19th centuries (Breidbach, Ghiselin, 2002) is to be mentioned before all. This thinking style implying holistic worldview is intimately related to the “developmental thinking” (Sandvik, 2008), with the both having been quite significant for the biological way of thought in the 19th century.

One of peculiar ideas of Martynov’s ontogenetic systematics is a suggestion to replace “tree thinking” by some “cycle thinking” (Martynov, 2011b). Such a substitution seems to arise from his treatment of the taxon as the ontogenetic cycle and so looks consistent within the framework of conception under consideration. However, it is fundamentally incorrect from a perspective outlined above, according to which the taxon is not equal to the individual, which attribute being the ontogenetic cycle. According to this, the “tree thinking” concerns supra-organismal level of the living matter, its subject is the phylogeny. Quite to the contrary, the “cycle thinking” concerns its organismal level, its subject is individual ontogeny. Under such circumstance, these two thinking styles seem to designate two fundamentally different ontological entities, which cannot be comparable directly and hence cannot replace one another. At this point, Martynov makes quite naturally the same mistake as in the case of his equating taxon with ontogenetic cycle; he improperly mixes two levels of biotic organization.

It should be noticed that Martynov himself does not seemingly follow his suggested substitution. As a matter of fact, phylogenetic trees of quite a modern fashion appear in a number of his most recent publications, while schematically shown ontogenetic cycles are just added as “auxiliary” to those trees (Martynov, 2011b; Martynov, Schrödl, 2011). This clearly indicates that his “cycle thinking” cannot probably be realized in practical systematics, unlike the “tree thinking” that entails standard representation of the organismal diversity in the form of “tree of life”.

Taxonomic diagnosis and ontogenetic pattern

Taxonomic diagnosis takes quite significant place in systematic biology serving as a tool allowing to fulfill two important taxonomic tasks. One is intensional definition



of a taxon by indicating the traits delimiting it. Another is to provide a possibility for allocation particular specimens to particular taxa as reliably and unambiguously as possible. Accordingly, diagnosis must have a form of strong positive statement about the traits characterizing each of the taxa in a classification and observable in each of the specimens at hands.

Of the three principal versions of ontogenetic systematics recognized above, that of Ho does not go so deeply in taxonomic theory to consider taxonomic diagnoses. In its pattern cladistic version (as it is treated here), diagnoses of particular taxa include synapomorphies distinguishing them at a particular level of generality within the given hierarchy of defining characters (Platnick, 1982). These synapomorphies are inferred from observations on ontogenies, but no direct reference to the latter is implied to be included in respective diagnoses. At the same time, each of the apomorphic traits is presumed to be observable in the organisms to be allocated to the taxa recognized by those defining characters.

Martynov’s concept of taxonomic diagnosis presumes something appreciably different. Based on his definition of the taxon as ontogenetic cycle (see above), he proposes to consider taxonomic diagnosis as a statement about ontogenetic pattern of ancestral species of a taxon being diagnosed. In a more “extravagant” manner, it is suggested that “diagnosis of any taxon above species level… is a hypothesis about… ontogenetic cycle of a single ancestral species actually existed formerly” (Martynov, 2009a, p. 190). This is really a great innovation in the issues of epistemology of taxonomy; but it seems to be quite an unsuccessful one, which is seen from the below considerations.

To start with, it should be acknowledged that any scientific judgments are hypothetical by themselves, and this is true for the content and structure of particular classifications, hence the term “taxonomic hypothesis” (Panchen, 1992; Pavlinov, 1995). Such hypotheses are presumed to be testable by means of direct observations or indirect reliable evidence. This precondition puts certain quite strong limitation on a possibility to treat taxonomic diagnosis as a hypothesis about ancestral ontogeny.

As a matter of fact, ontogeny cannot be easily observed directly in most multicellular organisms, which alone seems to serve as a strong objection against the idea under consideration. This is unconditionally true for just the ancestral ontogenies; they can by no means be observed directly but are reconstructed based on comparative data on the fossil specimens of different ages. Therefore, a hypothesis of ancestral ontogeny cannot be

tested (verified or falsified) by direct observations. As to the use of comparative data as a kind of indirect evidence for such a hypothesis testing, this seems to be not a reasonable approach, either. Indeed, the fossil specimens, from which these data are taken, are to be first allocated to certain ancestral taxon for any hypothesis of respective ontogenetic pattern to be inferred properly. This allocation should evidently be based on some traits not included in the “ontogenetic diagnosis”, otherwise it is clearly a kind of “closed circle” argumentation. So just these traits, and not any ontogenetic pattern proper, constitute a really working taxonomic diagnosis elaborated by a taxonomist. And these traits cannot not seemingly be a subject of any testing procedure as long as the respective classification is considered as “the given” (in sense of Kearney, Rieppel, 2006). It turns out that, under such circumstances, even if a hypothetical statement about ancestral ontogenetic pattern is thought to be tested in some or other way, it should be considered as something “external” to the diagnosis proper rather than a part of it.

As to the empirical application of the theoretical concept under consideration, inclusion of hypothetical ancestral ontogenetic patterns into a taxonomic diagnosis means evidently that any newly obtained specimen, in order to be allocated (or occasionally not) to a particular taxon, should be directly compared to that pattern. For this, ontogeny of such a specimen should be actually observed, and not reconstructed based on some indirect evidence, otherwise we have again a kind of “closed cycle” argumentation. It is evident that such an observation is principally impossible for the specimens came to a researcher in a dead or at least in an adult state, not to say about the fossils. So, Martynov’s concept of “ontogenetic diagnosis” seems to be largely impractical from the empirical standpoint, as the number of empirical situations, in which such a diagnosis can be actually applied, is extremely small. At most, keeping in mind basic premises of the ontogenetic systematics, its really working taxonomic diagnoses should include the traits, which are shown to correlate with (derived from) supposed ancestral ontogenetic patterns.

It should be noted, for the sake of fairness, that Martynov himself seems to agree with the latter conclusion. As a matter of fact, systematic diagnoses he gives for the taxa recognized by him include traditional lists of morphological traits (Martynov, 2011a,b). As to the ancestral ontogenetic cycles, they are provided just as additional taxonomic characteristics, along with several others (contents, recapitulation, etc.). So his claim for a new concept of taxonomic diagnosis turns out to be a kind of an unjustified “beau aphorism”, like the above concept of the taxon as ontogenetic cycle.

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At any rate, with this claim being made by Martynov, it occurs to me that the principal mistake with the concept of “ontogenetic diagnosis” is that a practical diagnosis of a particular taxon recognized in a classification is incorrectly taken for a theoretical definition of the taxon as a conceptual construct. To be true, taxonomic allocation (identification) of specimens is quite often called in practice just the “definition” (at least in Russian); but when foundations of a theoretical taxonomic conception are dealt with, such a confusion should be obviously avoided as undoubtedly mistaken.

Martynov’s model of ontogenetic evolution in Bilateria

Actually, ontogenetic systematics should not be obligatory interpreted evolutionary. This is true before al for pattern cladistics, which is not evolutionary; particular evolutionary scenarios are but conditionally added a posteriori to ontogeny-derived classifications (Nelson, 1974, 1989; Platnick, 1982; Patterson, 1983; see also above). Argumentation scheme of Ho (1992) does include phylogenetic interpretation of the inferred “ontogenetic tree”, but this is not an obligatory part of the implied procedure, because it is principally possible to convert this tree directly into a classification without referring to any phylogeny. In Martynov’s approach, evolutionary scenarios are secondary relative to classifications in the same manner as in pattern cladistics. However, reconstruction of evolution of ontogenetic cycles (patterns) is claimed by him to be the core of his version of ontogenetic systematics (Martynov, 2009a,b, 2011a). In this connection, certain attention is to be paid to the general model Martynov suggests to the ontogenetic evolution in Bilateria.

First, it is worthy to consider a theoretical component of Martynov’s evolutionary model. Based on his treatment of ontogenetic cycle as a unit of classification and, further, on “deductive” relation of evolutionary scenarios to classifications (see above), he considers phylogeny “not as a continual line, but as succession of sets of particular functional organizations” (Martynov, 2011b, p. 206). By this, Martynov seems to proclaim two important ideas concerning the nature of biological evolution. First, units of evolution “after Martynov”, just as those of his classifications, are not populations (or species or else) but rather ontogenetic cycles; or, in other words, the particular individuals with their ontogenies. Second, such evolution goes in not a continual but rather in a saltationary manner. In this respect, this model resembles remarkably the evolutionary concept of R. Goldschmidt (1940; Dietrich, 2000) also presuming saltationary evolution at the organismal level (his “hopeful monsters”).

Inasmuch as the actual Bilaterian evolution suggested by Martynov is concerned, the model under consideration can be roughly represented as a combined effect of but two principal evolutionary modi, viz. progress and regress (Martynov, 2009a,b, 2011a,b). This means, if taken literally, that all evolutionary transformations of ontogenetic patterns are prescribed to go along the same organizational line, either progressively or regressively. It implies in particular, following supposedly classical “law of recapitulation”, that juvenile stages are always plesiomorphic while adult stages are always apomorphic (Martynov, 2011b). Such a model does not seemingly presume any significant “side shifts” of evolutionary transformations that may lead to emergence of new directions in the evolution of ontogenetic (and eventually any morphological) patterns.

This oversimplified model, if correctly interpreted by me, contradicts strongly the presently predominating divergent conception of biological evolution represented metaphorically by the above branching “tree of life”. As a matter of fact, Martynov’s model strangely enough revives an old naturphilosophical idea of the linear “Scala Naturae”, or “Scale of Perfection”, quite popular in the 18th century (Lovejoy, 1936). As a result, with Martynov’s model in effect, it remains unexplained why and how different Bilaterian phyla appeared, which are characterized by quite different basic ontogenetic patterns incapable to be ordered on a single scale.

However, this standpoint becomes easily understood if one takes into account that the model in question was inferred by Martynov (2011a) based on investigations of only post-larval ontogenetic stages of few external structures in but a few orders belonging to two Bilaterian phyla, of about 30 or more recognized nowadays (Zhang, 2011). Not going deeply inside of Martynov’s factual arguments, one may just suppose that the data at his hands have actually made possible such evolutionary inferences for the particular taxa studied by him. However, I am more than skeptical about a possibility to extrapolate this particular model of evolution of post-larval ontogenesis in few Bilaterian taxa onto the entire ontogenetic pattern, including pre-larval stages of transformation of all internal organs, for all Bilaterians regardless of their significant differences in this pattern. As a matter of fact, the model suggested by Martynov contradicts evidently a well established evolutionary theory of the Bilaterian ontogeny, according to which most significant divergent evolutionary changes occurred at the earlier developmental stages (Ivanova-Kazas, 1995). Therefore, it seems to me that Martynov is wrong to rise unreasonably high the level of generality of his partial model of ontogenetic evolution.



CONCLUSIONS

Ontogenetic (or developmental) systematics is designed to recognize and to characterize taxa in a classification based on ontogenetic patterns of organisms belonging to them. It was dominating for a long time in systematic biology but was forced out of its leading position by reducing approaches emerged in the second half of the 20th century.

This taxonomic doctrine, in its widened treatment, represents currently rather a heterogeneous pool of unrealized declarations and poorly formulated concepts than a kind of well formulated consistent taxonomic conception comparable, say, to Hennigian cladistics. As a matter of fact, it combines under an unified title several pretty different approaches, including those which have been initially elaborated within cladistics (pattern cladistics of Nelson—Platnick) and rational taxonomy (approach of M.-W. Ho). Along with these (and several others less pronounced, such as Orton’s or Albert’s) approaches, there is one suggested most recently by A.V. Martynov as just the ontogenetic systematics. It looks as if most strongly developed at first glance but is actually most weakly founded under more close consideration.

By some general methodological principles inherited to the above conceptions, they can be first divided into two main categories, in which taxa are recognized based on either ontogenetic principles only (pattern cladistics) or on combined ontogenetic and phylogenetic principles (approaches of Orton, Ho, and Martynov). Based on another ground, they can be divided into two other as large categories, viz. “ontogeny-based” (pattern cladistics, Orton, Ho) and “ontogeny-interpreted” (Martynov).

Being “ontogeny-based” means that analysis of diversity and transformations of ontogenetic patterns precedes recognition of taxa and construing classifications; the approaches implying this methodology are really “eu-ontogenetic”. Contrary to this, being “ontogeny-interpreted” means that conclusions about diversity and transformations of ontogenetic patterns are inferred a posteriori from classifications previously obtained some or other way; such an approach can be called “pseudo-ontogenetic” (by analogy with the above “pseudo-phylogenetic”).

Inasmuch as Martynov’s version of ontogenetic systematics represents a “focal point” of the present issue, it deserves some more detailed concluding comments. In general, it is an eclectic combination of hardly compatible principles borrowed from different classificatory

conceptions and thus can be characterized aphoristically as a “cladistically interpreted phenetic typology”. More specifically, its own basic principles developed within this approach are all ill-founded; namely, (a) empirical hierarchical arrangement of classifications cannot be taken for a fundamental theoretical principle of the entire systematics; (b) taxon cannot be equated with ontogenetic cycle, so (c) the latter cannot be treated as a unit of systematics; (d) “cycle thinking” cannot replace “tree thinking”; (e) taxonomic diagnosis cannot be treated as a hypothesis of ancestral ontogenetic cycle. At last, Martynov’s “new model” of ontogenetic evolution in Bilateria seems to be oversimplified and can be estimated as but an unreasonably broad extrapolation.

All this makes Martynov’s version of ontogenetic systematics internally controversial and scientifically inconsistent with respect to its both ontological and methodological backgrounds. In other words, this taxonomic construct cannot be considered as a properly developed scientific conception in its strict sense, i.e. as a total of internally compatible and externally consistent concepts and definitions.

However, the above basic assumption of ontogenetic systematics, considered in general, makes it biologically quite meaningful and quite consistent with recent conception of Evo—Devo, in which phylogeny is treated as historical development of ontogenetic (or rather epigenetic, see Shishkin, 2006) programs. By this, this taxonomic school differs for the better from both the ultra-reducing molecular phylogenetic and the “integrative” taxonomy (in sense of Dayrat, 2005), which is phenetic by its methodology.

Therefore, it looks like this general classificatory approach has a large internal capacity. This allows to suppose that, when the current reducing trend in systematic biology subsides and the latter becomes again more biologically sound (Wheeler, 2008), ontogenetic (developmental) systematics will actually receive due attention and proper conceptual development. So, its current not very hopeful state may simply indicate that its time dose not come yet.

ACKNOWLEDGMENTS

I am greatly thankful to A. V. Martynov (Zoological Museum, Moscow Lomonosov State University) for his explanations of some of his ideas, and to A.V. Sysoev (the same museum) for his comments on my criticisms. Besides, Dr. A. Minelli (Department of Biology, University of Padova) provided useful comments on an earlier draft of the paper.

igOr ya. PaVlinOV


REFERENCES

Albert VA, Gustafsson MHG, Di Laurenzio L (1998) Ontogenetic systematics, molecular developmental genetics, and the angiosperm petal. In Molecular systematics of plants, II, DNA sequencing. Soltis P, Soltis D, Doyle J (eds). Boston: Kluwеr Acad. Publ., 349–374.

Aleev YuG (1986) Ecomorphology. Kiev. 423 pp. (in Russian)Babbitt CC (2005) Developmental systematics: Synthesizing

ontogeny and phylogeny in the Malacostraca (Crustacea). Abstr. Ph.D. Dissert. Chicago. URL elibrary.ru/item.asp?id=9066324.

Breidbach O, Ghiselin MT (2002) Lorenz Oken and Naturphilosophie in Jena, Paris and London. History & Philosophy of the Life Science 24: 219–247.

Brigandt I (2009) Natural kinds in evolution and systematics: metaphysical and epistemological considerations. Acta Biotheoretica, 57: 77–97.

De Craene LPR (2010) Floral Diagrams. An Aid to Understanding Flower Morphology and Evolution. Cambridge (UK): Cambridge Univ. Press. 458 pp.

de Queiroz K (1988) Systematics and the Darwinian revolution. Philosophy of Science 55: 238–259.

de Queiroz К, Gauthier J (1992) Phylogenetic taxonomy. Annual Review of Ecology and Systematics 23: 449–480.

Dietrich MR (2000) From hopeful monsters to homeotic effects: Richard Goldschmidt’s integration of development, evolution, and genetics. American Zoologist 40: 738–747.

Dayrat B (2005) Towards integrative taxonomy. Biological Journal of the Linnean Society 85: 407–415.

Dogel VA (1975) [Invertebrate Zoology]. Moscow: Vysshaya Shkola Publ. 559 pp. (in Russian)

Eldredge N, Cracraft J (1980). Phylogenetic patterns and the evolutionary process. N.Y: Columbia Univ. Press. 349 pp.

Ereshefsky M (2001) The poverty of the Linneaean hierarchy: A philosophical study of biological taxonomy. N.Y.: Cambridge University Press. 316 pp.

Ereshefsky M (2008) Systematics and taxonomy. In A companion to the philosophy of biology. Sarkar S, Plutynski A (eds). Oxford: Blackwell Publ., 99–118.

Feliner GN, Fernandez IA (2000). Biosystematics in the 90s: Integrating data from different sources. Portugaliae Acta Biologica 19: 9–19.

Goldschmidt R (1940) The material basis of evolution. New Haven: Yale University Press. 436 pp.

Goodwin B (1994) Homology, development, and heredity. In: Homology: The hierarchical basis of comparative morphology. Hall BK (ed.). N.Y.: Academic Press: 229–247.

Gould SJ (1977) Ontogeny and phylogeny. Cambridge (MA): Belknap Press, 491 p.

Hawksworth DL, Bisby FA (1988) Systematics: the keystone of biology. In Prospects in systematics. Hawksworth DL (ed.). Systematic Association Special Vol. 36. Oxford: Clarendon Press, 3–30.

Hennig W (1966) Phylogenetic systematics. Urbana (IL): Univ. Illinois Press. 263 pp.

Ho MW (1990) An exercise in rational taxonomy. Journal of Theoretical Biology 147: 43–57.

Ho MW (1992) Development, rational taxonomy and systematics. Biological Forum 85: 193–211.

Ho MW, Saunders PT (1993). Rational taxonomy and the natural system, with particular reference to segmentation. Acta Biotheoretica 41: 289–304.

Hull DL (1970) Contemporary systematic philosophies. Annual Review of Ecology and Systematics 1: 19–54.

Huxley J (1940). Introductory: towards the new systematics. In The New Systematics. Huxley J (ed.). L.: Oxford Univ. Press, P.1–46.

Ivanova-Kazas OM (1995) [Evolutionary embriology of animals]. SPb: Nauka, 565 pp. (in Russian)

Kearney M, Rieppel O (2006). Rejecting ‘‘the given’’ in systematics. Cladistics 22: 369–377.

Kholodnaya MA (2004) [Cognitive styles. On the nature of individual mind], 2d ed. SPb: Piter Publ. 384 pp. (in Russian)

Kluge AG, Srauss RE (1985) Ontogeny and systematics. Annual Review of Ecology and Systematics 16: 247–268.

Leontiev DV, Akulov AYu (2004) Ecomorpheme of the organic world: An experience of its inferring. Journal of General Biology, 65: 500–526. (in Russian, with English summary)

Levit GS, Meister K (2006) The history of essentialism vs. Ernst Mayr’s ‘‘Essentialism Story’’: A case study of German idealistic morphology. Theory in Biosciences 124: 281–307.

Lines JL, Mertens TR (1970) Principles of biosystematics. Chicago: Educational Methods. 137 pp.

Lovejoy AO (1936) The Great Chain of Being. Cambridge (MA): Harvard Univ. Press. 382 pp.

Martynov AV (2009b) Toward a synthesis of taxonomy, ontogeny and phylogeny: A new conception of ontogenetic systematics. Moscow University Bulletin (Vestnik) Ser. 16. 4: 17–21. (in Russian, with English summary)

Martynov AV (2009а) From ontogeny to evolution: Systematics in anticipation of the paradigm change. In Evoluiton and systematics: Lamarc and Darwin in contemporary research. Sviridov A.V, Shatalkin AI (eds). M.: Moscow Univ. Publ., 145–230. (in Russian, with English summary)

Martynov AV (2011a) Ontogenetic systematics and a new model of evolution of Bilateria. M.: KMK Sci. Press. 286 pp. (in Russian, with English summary)

Martynov AV (2011b) From “tree-thinking” to “cycle-thinking”: Ontogenetic systematics of nudibranch mollusks. Thalassas 27: 193–224.

Martynov A, Schrödl M (2011) Phylogeny and evolution of corambid nudibranchs (Mollusca: Gastropoda). Zoological Journal of the Linnean Society 163: 585–604.

Nelson GJ (1974) Classification as an expression of phylogenetic relationships. Systematic Zoology 22: 344–359.

Nelson G (1989) Cladistics and еvolutionary models. Cladistics 5: 275–289.



O’Hara RJ (1997) Population thinking and tree thinking in systematics. Zoologica Scripta 26: 323–329.

Orton GL (1955) The role of ontogeny in systematics and evolution. Evolution 9: 75–83.

Panchen AL (1992) Classification, evolution, and the nature of biology. Cambridge (UK): Cambridge Univ. Press. 398 pp.

Patterson C (1983) How does ontogeny differ from phylogeny? In Development and evolution Goodwin BC, Holder N, Wylie CC (eds). Cambridge (UK): Cambridge Univ. Press, 1–31.

Pavlinov IYa (1995) Classification as a hypothesis: enterring the problem. Journal of General Biology 56: 411–424. (in Russian, with English summary)

Pavlinov IYa (2005) Introduction to contemporary phylogenetics. M.: KMK Sci. Press. 391 pp. (in Russian)

Pavlinov IYa (2007a) Etudes on metaphysics of contemporary taxonomy. In The Linnaean Miscellanea. Pavlinov IYa (ed.). M.: Moscow Univ. Publ., 123–182. (in Russian, with English summary)

Pavlinov IYa (2007b) Phylogenetic thinking in the modern biology. Journal of General Biology 68: 19–34. (in Russian, with English summary)

Pavlinov IYa (2010) Comments on biomorphics (ecomorphological systematics). Journal of General Biology 71: 187–192. (in Russian, with English summary)

Pavlinov I.Ya. (2011) How it is possible to construct taxonomic theory. Zoologicheskie issledovania, 10: 45–100. (in Russian, with English summary)

Pavlinov IYa, Lyubarsky GYu (2011) Biological systematics: Evolution of ideas. M.: KMK Sci. Press. 667 pp. (in Russian)

Platnick NI (1982) Defining characters and evolutionary groups. Systematic Zoology 31: 282–284.

Quine WVO (I969) Ontological relativity and other essays. N.Y.: Columbia Univ. Press. 165 рp.

Remane A (1956) Grundlagen des Naturlichen Systems, der Vergleichenden Anatomie und der Phylogenetik. Theoretische Morphologie und Systematik. 2. ufl. Leipzig: Akademische Verlag. 364 ss.

Sandvik H (2008) Tree thinking cannot taken for granted: Challenges for teaching phylogenetics. Theory in Biosciences 127: 45–51.

Shishkin MA (2006) Development and lessons of evolution. Ontogenesis, 37: 179–198. (in Russian, with English summary)

Stace CA (1989) Plant taxonomy and biosystematics, 2d ed. Cambridge (UK): Cambridge Univ. Press. 264 pp.

Stuessy TF (2008) Plant taxonomy. The systematic evaluation of comparative data, 2d ed. N.Y.: Columbia Univ. Press, 568 рp.

Wägele J-W (2005) Foundations of phylogenetic systematics. München: Dr. Friedrich Pfeil Verlag. 365 рp.

Webster G, Goodwin B (1996) Form and transformation: Generative and relational principles in biology. Cambridge (UK): Cambridge Univ. Press. 287 рp.

Wheeler QD (2008) Introductory: Toward the new taxonomy. In The New Taxonomy. Wheeler QD (ed.). Boca Raton (FL): CRC Press, 1–17.

Wiley EO (1981) Phylogenetics: The theory and practice of phylogenetic systematics. N.Y.: John Wiley, Sons. 439 pp.

Zhang Z-Q (2011) Animal biodiversity: An introduction to higher-level classification and taxonomic richness. Zootaxa 3: 7–12.

(Received: September, 19, 2012; Accepted: March, 5, 2013)

A Critical Analysis of A.V. Martynov’s Version of Ontogenetic Systematics

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