Homologous Characters Research Articles

Phylogeny of Pyroleae (Ericaceae): implications for character evolution

Pyroleae (Ericaceae) consist of four genera, all of which are distributed widely in temperate coniferous or sometimes deciduous forests of the Northern Hemisphere. To investigate the phylogenetic relationships among these genera and to explore the evolution of the characteristics of the subfamily, we conducted maximum parsimony and Bayesian analyses with nrDNA ITS and three cpDNA intergenic spacers (atpB-rbcL, trnS-trnG and trnL-trnF). The results from cpDNA and combined cpDNA+ITS data sets strongly support the monophyly of Pyroleae as well as a sister relationship between Pyrola and Moneses-Chimaphila, with Orthilia as the basal lineage. The sister-group relationship between Moneses and Chimaphila is supported by a set of synapomorphies, e.g., single flower, colpate pollen, five bundles in the style, straight fruiting pedicel orientation, complete capsule dehiscence, and the basic chromosome number, x=13. The Moneses-Chimaphila-Pyrola clade is supported by at least one homologous character of pollen in tetrads. Conflicts associated with the phylogenetic position of Orthilia may imply a hybrid origin for it, and therefore further study is needed.

A critical review of ontogenetic development in Terebellidae (Polychaeta)

AbstractGarraffoni, A.R.S. and Lana, P.C. 2009. A critical review of ontogenetic development in Terebellidae (Polychaeta). —Acta Zoologica (Stockholm) 91: 390–401.This study reviews the ontogenetic variability of the head, the first segments and the uncini in Terebellidae, based on primary literature and development series of four terebellid species. We test hypotheses on character homologies and indicate informative characters for future phylogenetic analyses. The prostomium, identified as the region above the prototroch band of the larva, in addition to being the region of origin of the buccal tentacles, contains a series of nerves originating from the cerebrum. The peristomium, which contains the mouth, is innervated by the stomogastric nerve and consists of upper and lower lips and an internal pharynx. The loss of the first notochaetae and neurochaetae in the course of development is a recurrent pattern in terebellids. The claviform chaetae disappear with age and growth, and can be used to define the larval stage. Chaetogenesis shows that the long shaft‐shaped manubrium and posterior process develop from different regions. The uncini terminology ‘double rows’ was reinterpreted and renamed ‘inverted rows’, which better reflects the inversion of chaetal positions during ontogenetic development.

Promoting Resolution of the Percomorph Bush: A Reply to Mooi and Gill

Promoting Resolution of the Percomorph Bush: A Reply to Mooi and Gill

From Haeckel’s phylogenetics and Hennig’s cladistics to the method of maximum likelihood: Advantages and limitations of modern and traditional approaches to phylogeny reconstruction

The maximum likelihood and Bayesian methods are based on parametric models of character evolution. They assume that if we know these models as well as distribution of character states in studied organisms, we can infer the probability of different phylogenetic trajectories leading from ancestors to modern forms. In fact, these methods are mathematized variants of the traditional Haeckel’s approach to phylogeny reconstruction. In contrast to classical and parsimonious cladistics, they infer phylogenies without such limitations as necessity of strictly dichotomous evolution, exclusion of plesiomorphic characters, and acceptance of only holophyletic taxa. They assume that evolution may be reticulated, any homologous characters—both apomorphic and plesiomorphic—can be used for inferring phylogenies, and interpretation of evolutionary lineages as taxa is optional. Thus, the main difference between the new and more traditional approaches to phylogeny reconstruction lies not in the characters used (molecular or morphological) but in the methodology of analysis. It must be admitted that a revolution began in phylogenetics 10–20 years ago. However, the fundamental changes in phylogenetics have been carried out so calmly and neatly by the people who started this revolution, that many systematists still do not realize their importance.

Phylogenies without Synapomorphies—A Crisis in Fish Systematics: Time to Show Some Character

We contend that the move away from providing character evidence with phylogenies has diminished fish systematics and systematics in general, and amounts to a crisis. Present practices focus on solutions to matrices rather than on character homology, and rely on algorithms and statistics rather than biology to determine relationships. Optimization procedures in tree-building programs are phenetic and no longer employ homology, the original foundation of cladistics. Evidence for phylogenies is presented in a manner that obscures character conflict and makes meaningful debate difficult. The role of morphological characters has largely been reduced to their optimization and reinterpretation on the revealed “truth” of molecule-based topologies. All of this has resulted in a schism between molecular and morphological phylogeneticists. We examine several examples, focusing on Percomorpha and Gobioidei, to illustrate the shortcomings of recent approaches. We feel that phylogenetics can only move forward by recognizing that molecules are small-scale morphology; molecular data are not substantively different from larger-scale morphological data and should be treated in much the same manner. Careful investigation of homology and transparent presentation of evidence will keep our work and our science relevant. We suggest four measures that need reintroduction to phylogenetic practice in order to bring systematics back to its fundamental principles: (1) examine data quality, character distribution, and evidence; plot characters to identify and examine character conflict, and weigh evidence for homology, (2) explore the nature of character information—data become characters only after they are understood, (3) question assumptions of methods, common practice is not necessarily indicative of the ideal analysis, (4) in particular, question and investigate optimization as a method and what its impact is on character homology and the meaning of synapomorphies; use biology, not algorithms to make homology decisions.

Classification of the flea families (Siphonaptera): I. Family Hystrichopsyllidae (Part 5)

Based on analysis of homologous character states and considering the molecular-biological data (Whiting et al., 2008), phylogenetic relationships of the tribes and subfamilies of the family Hystrichopsyllidae are discussed. In some cases, homologous states of the skeleton characters mark the clades revealed by the moleculargenetic analysis, but are shared by taxa from other clades. In contrast to the molecular-genetic data, morphological characters indicate the phylogenetic integrity of the family Hystrichopsyllidae. Morphological characters depict the subfamily Anomiopsyllinae as a monophyletic taxon (having synapomorphic states of the metaphragma, metasternite, and the mesosternal apodeme) closest to the subfamilies Neopsyllinae and Rhadinopsyllinae. The subfamilies Neopsyllinae, Rhadinopsyllinae, and Stenoponiinae have a non-thickened metasternite; the former two subfamilies also have in common a similar structure of articulation of the digitoid with the clasper, type of the metaphragma modification, and the presence of the sclerotized central sclerite. Homologous modifications of the metaphragma are also present in fleas of the subfamily Stenoponiinae. Close to this group are the subfamily Hystrichopsyllinae whose representatives also possess non-thickened metasternal apodemes, and the subfamily Listropsyllinae with its frontal sclerotized tubercle being a specialized modification of the frontal sclerotized fold. A specific feature shared by fleas of the subfamilies Hystrichopsyllinae and Listropsyllinae is the presence of the metasternal furca with high sharp processes and a high medial ridge. The closeness of these taxa is supported by the results of molecular-genetic analysis. The subfamilies Doratopsyllinae and Ctenophthalminae (tribes Ctenophthalmini and Carterettini) are united by the type of the attachment of the mesopleural rod to the special ridge at the upper margin of the mesopleuron. According to the molecular-genetic data, the tribe Neotyphloceratini is related to these subfamilies, even though its members have no ridge on the mesopleuron. The similarity in the structure of the furca (the presence of high dorsal processes with rounded apices and a high median ridge) and in the length ratio of the fulcrum lobes relates the subfamilies Ctenophthalminae and Dinopsyllinae.

Balaenophilus manatorum (Ortíz, Lalana and Torres, 1992) (Copepoda: Harpacticoida) from Loggerhead Sea Turtles, Caretta caretta, from Japan and the Western Mediterranean: Amended Description and Geographical Comparison

The ectoparasitic harpacticoid copepod, Balaenophilus manatorum (Ortíz, Lalana and Torres, 1992) (syn. Balaenophilus umigamecolus Ogawa, Matsuzaki and Misaki, 1997), has been reported on 3 species of marine turtles from the Pacific and the Mediterranean and from the West Indian manatee off Cuba in the Caribbean. The 3 available descriptions of this species were made using light microscopy. In this paper, we provide an amended description of B. manatorum using scanning electronic microscopy (SEM) for specimens in the collection from which B. umigamecolus was originally described. This material was collected from 1 loggerhead sea turtle, Caretta caretta, from Japan. The use of SEM allowed us to add several new microcharacters to the original description but, more importantly, allowed us to correct a number of the traits originally described. Some of the corrections could affect the interpretation of putative homology and variability of characters among populations of B. manatorum. A SEM comparison of specimens of B. manatorum from loggerheads from Japan and the western Mediterranean suggested the existence of morphological stasis between these populations. However, there were apparent meristic differences with a recently published description of this species from olive ridleys, Lepidochelys olivacea, in Mexico. Although B. manatorum is currently considered as a single, widespread taxon, the possibility that it actually represents a species complex deserves further attention.

Evidence for Species Recognition on the Basis of a Single Specimen: Nephelolejeunea carcharias sp. nov. (Lejeuneaceae: Jungermanniopsida)

Species proposed on the basis of one or few individuals present a difficulty that transcends all modes of inference and all systematic data sources, including morphological and molecular data. This is particularly true for the liverwort family Lejeuneaceae, as these plants are inherently variable, differences between groups are frequently quantitative, and few specimens or limited material preclude destructive investigations, including molecular approaches. Here we use an extreme case of a single specimen to demonstrate how an integrated approach to character assessment and transparent decision processes can be used to provide sufficient evidence to support the hypothesis of species differences. To make progress on the single-specimen problem, an assessment of homology is essential to discriminate intra from interspecific variation in characters. Furthermore, an assessment of homology can substantiate differences between species of leafy liverworts in situations where the weight of character differences alone cannot because it is grounded in a phylogenetic framework. When homologous character systems and character states are equated with difference, the absence (or at least delayed development) of a stipe in Nephelolejeunea carcharias provides sufficient evidence for us to reject the hypothesis that this species is the same as N. talinayi because of what we know about the expression of perianth stipes in related species. As an inferential tool, homology exhibits considerable utility to liverwort taxonomists because it furnishes us with reasonable grounds on which to test hypotheses of relationship even in extremely observation-limited situations such as the one treated here.

Lemma micromorphological characters in the Chloridoideae (Poaceae) optimized on a molecular phylogeny

Eight lemma micromorphological characters of 83 taxa representing 61 genera in the Chloridoideae have been investigated using Scanning Electron Microscopy, including long cells, cork cells, stomata, bicellular microhairs, papillae, silica cells, microprickles, and macrohairs. Five new types of lemma micromorphological characters were reported here. Data for 27 taxa representing 19 genera from previous publications were also supplied to access the homology of lemma micromorphological characters for different groups through optimization onto a molecular cladogram. Given the optimization, five characters including long cells, cork cells, stomata, papillae, microprickles are of phylogenetic significance for supra-generic groups. Seven characters including straight outline long cells, crescent-shaped cork cells, absent stomata, absent papillae, dumb-bell-shaped silica cells, c-type microprickles, and papillate-base macrohairs may not be homologous, however, the enneapogonoid-type bicellular microhairs appeared as a synapomorphy for the Chloridoideae.

Combining phylogenetic information: concept, methodology, and challenges

The DNA sequences, morphological and other homologous characters can be used to infer the origins and histories of biological taxa. Combining all the phylogenetic information available can produce more inclusive phylogenies, improve our understanding of living organisms, and enable biologists to prompt and test hypotheses on a larger scale and with stronger statistical power. In this article, the concept of combining phylogenetic information and its comparison with traditional analysis were reviewed. The most popular approaches of supertree and supermatrix were discussed in detail, and novel ways were presented. Although the combining analysis is facing rigid challenges from data and foundation, it is currently the only approach for realization of the Tree(Net) of Life, and its development will definitely expand our knowledge of evolution on the earth and contribute to the progress of evolutionary related disciplines.

A re-evaluation of genus Chaetomidium based on molecular and morphological characters

Chaetomidium, a genus in the Chaetomiaceae, comprises 12 species that produce similar cleistothecial ascomata with a membranous, mostly pilose, peridium. Approximately six species of this genus produce some type of modified peridium composed of cephalothecoid plates that previous authors have hypothesized to be a homologous character within the genus. To better understand the phylogenetic affiliations of Chaetomidium and distribution of the cephalothecoid peridium within this genus we performed phylogenetic analyses with LSU, β-tubulin and rpb2 sequence data. The results of these analyses showed that Chaetomidium is polyphyletic and should be restricted to its type, C. fimeti, and C. subfimeti. The remaining cephalothecoid and non-cephalothecoid species were scattered throughout the Chaetomiaceae and Lasiosphaeriaceae. The cephalothecoid species of Chaetomidium were distributed in three unrelated clades, suggesting that the morphological similarity among these particular species resulted from convergence instead of ancestry.

Phylogenetic studies of the core Alismatales inferred from morphology and rbcL sequences

The phylogeny of Alismatales remains an area of deep uncertainty, with different arrangements being found in studies that examined various subsets of genes and taxa. Herein we conducted separate and combined analyses of 103 morphological characters and 52 rbcL sequences to explore the controversial phylogenies of the families. Congruence between the two data sets was explored by computing several indices. Morphological data sets contain poor phylogenetic signals. The homology of morphological characters was tested based on the total evidence of phylogeny. The incongruence between DNA and morphological results; the hypothesis of the ‘Cymodoceaceae complex’; the relationships between Najadaceae and Hydrocharitaceae; the intergeneric relationships of Hydrocharitaceae; and the evolutionary convergence of morphological characters were analyzed and discussed.

Systematics of Indo-Pacific fireflies with a redefinition of Australasian Atyphella Olliff, Madagascan Photuroluciola Pic, and description of seven new genera from the Luciolinae (Coleoptera: Lampyridae)

This major systematic revision of fireflies (Coleoptera: Lampyridae) concentrates on the genera related to Atyphella Olliff in the Luciolinae. Seven new genera and 19 new species are described, which with two exceptions occur in the area encompassed by Australia, the Republic of Palau, Federated States of Micronesia, Papua New Guinea, Indonesia (West Irian), Solomon Islands, New Caledonia, Vanuatu and Fiji. Keys to the genera and subgenera of the Luciolinae are included. The revision is based upon a phylogenetic analysis of 343 morphological characters of males, females and larvae of 112 Luciolinae species, including the type species of the six genera and four subgenera of the Luciolinae sensu McDermott (1966). The genus Atyphella Olliff is redefined and redescribed from 23 species including 14 endemic Australian species, and nine species from the wider study area. A. leucura Olivier, A. scabra Olivier and A. testaceolineata Pic are redescribed. A. palauensis Wittmer is elevated to species level from A. carolinae palauensis Wittmer and redescribed. Aquilonia gen. n. is described for Aq. costata (Lea), transferred from Atyphella Olliff. Convexa gen. n. is described for C. wolfi (Olivier), transferred from Atyphella. Gilvainsula gen. n. includes the new species, G. similismessoria sp. n., and G. messoria (Olivier), transferred from Atyphella Olliff. Lloydiella gen. n. includes four species; Ll. majuscula (Lea) transferred from Atyphella, and three new species, Ll. japenensis sp. n., Ll. uberia sp. n., and Ll. wareo sp. n. Pygatyphella (Ballantyne) is elevated to generic status from Luciola (Pygatyphella) Ballantyne and redescribed from 22 species including ten new species Pygat. japenensis sp. n., Pygat. karimui sp. n., Pygat. kiunga sp. n., Pygat. limbatifusca sp. n., Pygat. nabiria sp. n., Pygat. okapa sp. n., Pygat. russellia sp. n., Pygat. tomba sp. n., Pygat. uberia sp. n., and Pygat. wisselmerenia sp. n., with uberia representing specimens known in previous analyses as ‘Sisiak’. Pygat. eliptaminensis (Ballantyne), Pygat. marginata (Ballantyne), Pygat. peculiaris (Olivier) and Pygat. pulcherrima (Ballantyne) are transferred from Luciola (Pygatyphella) Ballantyne. Pygat. tagensis (Ballantyne), Pygat. hounensis (Ballantyne), Pygat. obsoleta (Olivier), and Pygat. undulata (Pic) are transferred from Atyphella Olliff; Pygat. obsoleta is reassessed, geographic varieties are suggested, and the species redescribed from a greatly expanded number of specimens. Pygat. ignota (Olivier), Pygat. plagiata (Blanchard) and Pygat. salomonis (Olivier) are transferred from Luciola Laporte and redescribed. Pygat. limbatipennis (Pic) is transferred from Atyphella salomonis var limbatipennis Pic, and redescribed. Magnalata gen. n. is described for three species, M. rennellia sp. n., M. limbata (Blanchard) transferred from Luciola, and M. carolinae (Olivier) transferred from Atyphella. Missimia gen. n. is erected for a single species M. flavida sp. n. based on four specimens dealt with in previous phylogenetic analyses as ‘Mt Missim’. Photuroluciola Pic is elevated to generic status from Luciola (Photuroluciola) Pic and redescribed from its single species Photuro. deplanata Pic. Asymmetricata gen. n. is erected for two SE Asian species As. ovalis (Hope) and As. circumdata (Motsch.), both transferred from Luciola and redescribed. Where available, females are associated and are characterised briefly. A. testaceolineata, M. limbata, Pygat. huonensis, Pygat. limbatipennis, Pygat. peculiaris, and Pygat. uberia sp. n. are identified by light patterns. Discussion addresses: the interpretation of female aptery, the extent of the labrum, numbering of abdominal segments using actual segment number, and use of the term ventrite to reflect visible abdominal sternites. Functional morphology of many terminal abdomen modifications is addressed as is the range and nature of colour patterns. Determination of polarity in various states of bipartite light organs is overviewed, as are problems with the homology of characters, and difficulties in interpretation of characters in soft bodied insects especially those preserved in ethanol.

Insights on Using Morphologic Data for Phylogenetic Analysis in Sedges (Cyperaceae)

Sedges are often viewed as difficult subjects for morphology-based phylogenetic analysis, due to several difficulties, including finding an adequate number of characters to yield well-resolved and well-supported trees, correctly assessing homology of characters and character states, and selecting appropriate outgroups for character state polarizations. The published literature holds only 11 papers with morphology-based phylogenetic analyses of sedges. This paper reviews those studies, and presents the phylogeny of two groups of sedges: (1) Carex section Deweyanae, and (2) Carex sections Careyanae, Granulares, and Griseae. This paper also presents recommendations for using morphologic data to reconstruct sedge phylogenies, based on comparisons of the trees resulting from the present study with the previous sedge studies and with similar studies of phylogeny of other groups of flowering plants. In the two groups of Carex examined, morphology does provide sufficient characters to infer well-resolved trees, with some nodes having good to strong support at levels consistent with those found in morphology-based analyses of other groups of flowering plants. The inclusion of micromorphologic and anatomic characters substantially enhances the resolving power of macromorphologic characters in sedge analyses, and increases the support for some clades.

African Dacus (Diptera: Tephritidae: Molecular data and host plant associations do not corroborate morphology based classifications

The genus Dacus Fabricius includes economically important pest fruit flies distributed in the Afrotropical and Indo-Australian regions. Two recent revisions based on morphological characters proposed new and partially discordant classifications synonymizing/revalidating several subgeneric names and forming species groups. Regardless these efforts, the phylogenetic relationships among Dacus species remained largely unresolved mainly because of the difficulties in assigning homologous character states. Therefore we investigated the phylogeny of African Dacus by sequencing 71 representatives of 32 species at two mitochondrial (COI, 16S) and one nuclear ( period) gene fragments. Phylogenetic relationships were inferred through Bayesian and Maximum Parsimony methods and hypotheses about the monophyly of Dacus subgenera were tested by Shimodaira–Hasegawa tests. The congruence tests and the analyses of the single gene fragments revealed that the nuclear gene supports similar conclusions as the two mitochondrial genes. Levels of intra- and inter-specific differentiation of Dacus species were highly variable and, in some cases, largely overlapping. The analyses of the concatenated dataset resolved two major bootstrap-supported groups as well as a number of well-supported clades and subclades that often comprised representatives of different subgenera. Additionally, specimens of Dacus humeralis from Eastern and Western African localities formed separate clades, suggesting cryptic differentiation within this taxon. The comparisons between the molecular phylogeny and the morphological classification revealed a number of discrepancies and, in the vast majority of cases, the molecular data were not compatible with the monophyly of the currently recognised subgenera. Conversely, the molecular data showed that Apocynaceae feeders are a monophyletic sister group of species feeding on both Cucurbitaceae and Passifloraceae (these latter being also monophyletic). These results show a clear association between the molecular phylogeny of African Dacus and the evolution of host plant choice and provide a basis towards a more congruent taxonomy of this genus.

What is a Genus in Cypereae: Phylogeny, Character Homology Assessment and Generic Circumscription in Cypereae

Using a DNA-based tree as the framework, the homology of key taxonomic characters in tribe Cypereae (900 species in 19 genera, the largest of which is Cyperus) is assessed and revisit the question of generic circumscription. Plastid DNA (rbcL gene, rps16 intron, trnL intron and trnL-F intergenic spacer) sequence matrix for 50 species in 19 genera of Cypereae is analysed using the maximum parsimony algorithm of PAUP. Two major groups are observed: the Ficinia and Cyperus clades. The Ficinia clade includes taxa with a center of diversity in the Cape Floristic Region of South Africa. These are predominantly perennial herbs (with exception of Isolepis, which is predominantly annual) having non-Kranz (C3) anatomy and spirally arranged glumes. Species of the Cyperus clade have a predominatly distichous glume arrangement and Kranz anatomy which is either absent (C3) or present (C4). Cyperus is the core genus in the Cyperus clade, in which 13 additional segregate genera are embedded. These segregate genera differ from typical Cyperus in one or more of a few gross morphological characters. There are no unambiguous characters separating C3 and C4 Cyperus species. The circumscription of Cypereae is broadened to include all taxa with a Cyperus-type embryo and perianth segments. Three taxa possessing perianth segments, namely Hellmuthia membranacea, Scirpus falsus and S. ficinioides, are supported to be closer to Cyperus than to Scirpus.

Phylogeny of Grumichellini Morse, 1981 (Trichoptera: Leptoceridae) with the description of a new genus from southeastern Peru

Osflintia manu, new genus, new species, of long-horned caddisfly (Leptoceridae: Triplectidinae: Grumichellini) is described and illustrated from southeastern Peru. The phylogeny of Grumichellini Morse (Leptoceridae: Triplectidinae) is revisited and hypotheses of homology of some morphological characters are reconsidered. The monophyly of the tribe is corroborated and the phylogenetic relationships of its included genera are inferred to be (Triplexa (Gracilipsodes ((Grumichella, Amazonatolica) (Atanatolica, Osflintia, n. gen.)))) from adult and larval characters. Diagnostic characters of the new genus include the following: reduced tibial spur formula (2, 2, 2), loss of forewing crossvein sc-r1, hind wing discoidal cell closed, hind wing fork IV present, pair of long setae on tergum IX of the male genitalia, and pair of processes on the apex of segment X.

A new genus and new species of metalmark moths (Lepidoptera: Choreutidae) from Costa Rica

Alasea, new genus, is described and illustrated. As currently defined, Alasea is monotypic with the single species A. corniculata, n. sp., from Heredia, Limón, and Puntarenas provinces in Costa Rica. The new genus is assigned to the subfamily Choreutinae based on morphological and molecular data. As in other choreutines, Alasea has a bluntly pointed forewing and hindwing (in Brenthiinae the wings are obtuse); the basal segment of the labial palpus is parallel-sided (in Brenthiinae it is narrowed basally); and the basal flagellomeres of the antenna are heavily scaled (in Brenthiinae such scaling is never present). The immature stages and the biology of A. corniculata are unknown. Additionally, the terminology and homology of genitalic characters used in descriptions of Choreutidae are reviewed, and suggestions for more consistent usage are provided.

A re-evaluation of the Dynomenidae Ortmann, 1892 (Crustacea, Decapoda, Brachyura, Podotremata), with the recognition of four subfamilies

A re-evaluation of the Dynomenidae Ortmann, 1892, on the basis of morphological characters, allows four subfamilies to be recognised, viz. Acanthodromiinae n. subfam., Dynomeninae Ortmann, 1892, Metadynomeninae n. subfam., and Paradynomeninae n. subfam. Sequences of character states for each homologous character (morphocline) show a similar polarity. The Acanthodromiinae n. subfam. exhibits a plesiomorphic condition, both in body shape and fronto-orbital disposition as well as in the condition of the thoracic sternum, abdominal holding mechanism and gill structure. Both the Metadynomeninae n. subfam. and Dynomeninae are more advanced, the latter being more “carcinized” and the most derived. The Paradynomeninae n. subfam. evolved a specialised frontal and buccal region, by forming a projecting “face”. The family Dynomenidae, which presently comprises merely five extant genera and 21 species, but with a worldwide distribution, is amongst the most ancestral brachyuran families, with a good fossil record from the Late Jurassic onwards. A few fossil genera such as Kromtitis Müller, 1984, and Kierionopsis Davidson, 1966, appear to conform to the Paradynomeninae n. subfam. A key to the subfamilies of extant Dynomenidae is provided.

A re-evaluation of the Dynomenidae Ortmann, 1892 (Crustacea, Decapoda, Brachyura, Podotremata), with the recognition of four subfamilies

A re-evaluation of the Dynomenidae Ortmann, 1892, on the basis of morphological characters, allows four subfamilies to be recognised, viz. Acanthodromiinae n. subfam., Dynomeninae Ortmann, 1892, Metadynomeninae n. subfam., and Paradynomeninae n. subfam. Sequences of character states for each homologous character (morphocline) show a similar polarity. The Acanthodromiinae n. subfam. exhibits a plesiomorphic condition, both in body shape and fronto-orbital disposition as well as in the condition of the thoracic sternum, abdominal holding mechanism and gill structure. Both the Metadynomeninae n. subfam. and Dynomeninae are more advanced, the latter being more “carcinized” and the most derived. The Paradynomeninae n. subfam. evolved a specialised frontal and buccal region, by forming a projecting “face”. The family Dynomenidae, which presently comprises merely five extant genera and 21 species, but with a worldwide distribution, is amongst the most ancestral brachyuran families, with a good fossil record from the Late Jurassic onwards. A few fossil genera such as Kromtitis Muller, 1984, and Kierionopsis Davidson, 1966, appear to conform to the Paradynomeninae n. subfam. A key to the subfamilies of extant Dynomenidae is provided.