Morphological evidence supporting the monophyly of the family Polynemidae (Teleostei: Perciformes) and its sister relationship with Sciaenidae

The monophyly of Polynemidae was evaluated and its sister relationship with Sciaenidae discussed, based on osteological and myological characters from 24 polynemid species in eight genera, with comparisons with acanthomorph fishes from literature and 86 species in 8 orders and 63 families examined. Polynemidae was inferred as a monophyletic group, strongly supported by 19 synapomorphies, including four unique characters (unnamed bone present on cephalic sensory canal extending from supratemporal, third actinost not supporting pectoral-fin rays, section A1 comprising lateral and medial elements, and division of obliquus inferioris present between lower postcleithrum and rod-like process on coracoid) in percoids. In addition, seven pectoral girdle characters were recognized, with the girdle possessing filament-like sensory rays, an adaptation to benthic life in muddy water. The sister relationship of Polynemidae and Sciaenidae was supported by six synapomorphies, including two rather rare (a single branchiostegal ray suspended by epihyal and posterior portions of pelvic bones on both sides interdigitated) and two unique characters (metapterygoid and quadrate interdigitated medially and anterior extension of the nasal canal).     

Phylogenetic relationships among atheriniform fishes (Teleostei: Atherinomorpha)

We present evidence from adult and larval morphology for the monophyly and relationships of Atheriniformes, using other atherinomorphs, mugilids and acanthomorph fishes as outgroups. Atheriniformes is diagnosed by ten characters (larval: short preanal length, single mid-dorsal row of melanophores; adult: vomerine ventral face concave, long Al muscle tendon to lacrimal, two anterior infraorbital bones, pelvic-rib ligament, pelvic medial plate not extended to anterior end, and second dorsal-fin spine flexible). We recognize six families within the order, the hierarchical relationships among which are: (Atherinopsidae (Notocheiridae (Melanotaeniidae (Atherionidae (Phallostethidae, Atherinidae))))). Other major conclusions include: (1) Atherinopsidae (Menidiinae, Atherinopsinae) is diagnosed by 20 characters (e.g. ethmomaxillary ligament attached to palatine dorsal process, ventral postcleithrum with two dorsal rami); (2) Melanotaeniidae (Bedotiinae (Melanotaeniinae (Telmatherinini, Pseudomugilini))) is diagnosed by six characters (e.g. absence of second dorsal-fin spine, sexual dimorphism in body colour and median-fin development, greater body depth); (3) Dentatherina is in Phallostethidae; (4) Atherinidae (Atherinomorinae (Craterocephalinae, Atherininae)) is diagnosed by three characters (lacrimal notch, ventral postcleithrum between first and second pleural ribs, pelvic ventral spine); (5) Atherinidae and Phallostethidae form the Atherinoidea clade diagnosed by seven characters (e.g. interopercle dorsal process absent, dorsal wings of urohyal absent, ventral postcleithrum laminar, pelvic medial plate extended to anterior end, presence of anal plate). Bedotia, Rhodes , and melanotaeniines are shown to be derived within atheriniforms rather than the plesiomorphic sister groups to a paraphyletic 'atherinoid' group. We also demonstrate that groups traditionally placed in Atherinidae (Menidiinae, Atherininae, Atherioninae, etc.) comprise a paraphyletic assemblage.     

Monophyly of the Citharidae (Pleuronectoidei: Pleuronectiformes: Teleostei) with considerations of pleuronectoid phylogeny

The monophyly of Citharidae, the pleuronectoid family thought to be a transitional group between the Psettodoidei and other typical pleuronectoids, has been in question mainly because of the lack of recognized synapomorphies for the family. In this study, the citharid skeleton is described, and the monophyly of the family and its phylogenetic position within the Pleuronectoidei are reassessed following a phylogenetic analysis based on 45 osteological, myological, and external characters. The Citharidae was found to represent a monophyletic group, supported by six synapomorphies (e.g., first dorsal proximal radials firmly wedged into notch of blind side lateral ethmoid; anterior dorsal proximal radials tightly mutually attached; blind side posterior nostril considerably enlarged). Two previously recognized subfamilies, sinistral Citharinae and dextral Brachypleurinae, are invalid because of their nonmonophylies. Interrelationships of the pleuronectoids shown herein are discussed. Received: February 19, 2001 / Revised: July 10, 2001 / Accepted: July 23, 2001     

Comparative morphology,phylogeny, and classification of West African callopanchacine killifishes (Teleostei: Cyprinodontiformes: Nothobranchiidae)

A phylogenetic analysis combining 63 morphological characters and DNA sequences (3296 bp), comprising segments of the mitochondrial genes 16S and ND2, and the nuclear gene 28S, for 19 taxa of the West African killifish tribe Callopanchacini and 11 out‐group taxa, highly supported the monophyly of the tribe, and made it possible to provide the first unambiguous diagnoses for the included genera (Archiaphyosemion, Callopanchax, Nimbapanchax, and Scriptaphyosemion). The monophyly of the Callopanchacini is supported by six morphological synapomorphies: posterior portion of the mandibular channel consisting of a single open groove; basihyal pentagonal, as a result of a nearly rectangular basihyal cartilage and a triangular bony support; dorsal process of the urohyal usually absent, sometimes rudimentary; presence of a wide bony flap adjacent to the proximal portion of the fourth ceratobranchial; a broad bony flap adjacent to the proximal portion of the fifth ceratobranchial; and haemal prezygapophysis of the pre‐ural vertebra 2 ventrally directed. The analysis indicates that the medially continuous rostral neuromast channel, commonly used to diagnose the tribe, is plesiomorphic. This study also indicates that, among African aplocheiloids, the annual life cycle style developed once in Callopanchax, and then again independently in the clade containing Fundulopanchax and Nothobranchius. © 2015 The Linnean Society of London     

Phylogeny of Recent Canidae (Mammalia, Carnivora): relative reliability and utility of morphological and molecular datasets

Zrzavý, J. & ?i?ánková, V. (2004). Phylogeny of Recent Canidae (Mammalia, Carnivora): relative reliability and utility of morphological and molecular datasets. — Zoologica Scripta, 33, 311–333. Phylogenetic relationships within the Canidae are examined, based on three genes (cytb, COI, COII) and 188 morphological, developmental, behavioural and cytogenetic characters. Both separate and combined phylogenetic analyses were performed. To inspect the phylogenetic ‘behaviour’ of individual taxa, basic phylogenetic analysis was followed by experimental cladistic analyses based on different data‐partition combinations and taxon‐removal analyses. The following phylogeny of the Recent Canidae is preferred: (1) Urocyon is the most basal canid; (2) Vulpes is a monophyletic genus (including Fennecus and Alopex); (3) the doglike canids (DC) form a clade (=Dusicyon + Pseudalopex + Lycalopex + Cerdocyon + Atelocynus + Chrysocyon + Speothos + Lycaon + Cuon + Canis), split into two subclades, South American and Afro‐Holarctic, with uncertain position of the Chrysocyon + Speothos subclade; (4) Canis is paraphyletic due to the position of Lycaon and Cuon. Otocyon and Nyctereutes are the most problematic canid genera, causing an unresolved branching pattern of Otocyon, Vulpes, Nyctereutes and DC clades. Reclassification of the two basal species of ‘Canis’ into separate genera is proposed (Schaeffia for ‘C.’ adustus, Lupulella for ‘C.’ mesomelas). Although the morphological dataset ranked poorly in both separate and simultaneous analyses (measured by number of minimum‐length topologies, relative number of resolved nodes in the strict consensus of all minimum‐length topologies, consistency and retention indices, nodal dataset influence, and number of extra steps required by the data partition to reach the topology of the combined tree), the morphological synapomorphies represent nearly one quarter of all synapomorphies in the combined tree. Among the hidden morphological support of the combined tree the developmental and behavioural characters are conspicuously abundant.     

A new species of spiny driftwood catfish Spinipterus (Siluriformes: Auchenipteridae) from the Amazon basin

An expedition to the middle Rio Purus basin uncovered a remarkable new species of the genus Spinipterus. The new species has a very distinct and conspicuous colour pattern resembling a jaguar and it is almost four times larger than Spinipterus acsi, a small specimen (32 mm L_S) from Caño Santa Rita, a right bank tributary of Río Nanay in Peru and a second specimen was reported from Rio Juruá, Amazonas State, Brazil. Although the new species is more similar in size and colour pattern to Liosomadoras, it shares the synapomorphies for Spinipterus. The new species differs from the congener by the following characters: (a) colour pattern with large black rosette-like spots over a light yellow to brown background (v. brown background with small dark blotches over the body); (b) adult body size reaching 104.5 mm L_S (v. maximum known size 37.1 mm L_S); (c) posterior process of cleithrum short, never reaching vertical through the dorsal-fin origin (v. posterior process long, surpassing vertical through the dorsal-fin origin); (d) seven soft pectoral-fin rays (v. six); (e) caudal fin truncated (v. caudal fin rounded).     

Morphology‐based phylogenetic analysis and classification of the family Rhinocryptidae (Aves: Passeriformes)

The family Rhinocryptidae comprises an assemblage of 12 genera and 55 species confined to the Neotropical region. Here we present the first morphology‐based phylogenetic study of the Rhinocryptidae, using 90 anatomical characters (62 osteological, 28 syringeal) scored for all genera of the family and representatives of all families of the infraorder Furnariides. Parsimony analysis of this dataset recovered 7428 equally most‐parsimonious trees. The strict consensus of those trees was completely resolved at the genus level, with the topology (Liosceles (Psilorhamphus ((Eleoscytalopus + Merulaxis) (Acropternis ((Teledromas + Rhinocrypta) ((Pteroptochos + Scelorchilus) (Eugralla (Myornis + Scytalopus)))))))). The monophyly of the Rhinocryptidae as presently understood was recovered with strong support [eight synapomorphies and Bremer support (BS) = 6). Strongly supported internal arrangements included the basal position of the Amazonian genus Liosceles relative to the rest of the family (four synapomorphies, BS = 4), a clade containing Acropternis through Scytalopus (six synapomorphies, BS = 4), and other less inclusive nodes. The main points of congruence between the present morphological phylogeny and previous molecular phylogenetic work on the family were clades supported by six or more synapomorphies and Bremer values of 6–7: Eleoscytalopus + Merulaxis (eight synapomorphies, BS = 6), Scelorchilus + Pteroptochos (seven synapomorphies, BS = 7), Rhinocrypta + Teledromas (seven synapomorphies, BS = 7), and Eugralla + Myornis + Scytalopus (six synapomorphies, BS = 6). A classification derived from the morphological phylogeny is proposed, with new suprageneric taxa being named and diagnosed. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 377–432.     

A new species of Sturisoma (Loricariidae: Loricariinae) from the Madre de Dios River basin,Peru, with a key to all congeners and comments on the type series of Sturisoma rostratum

A new species of the genus Sturisoma from the Madre de Dios River, upper Madeira, Peru, is described. The new species can be differentiated from its congeners by the following characteristics: dorsolateral stripe reaching to less than half, or only half length of caudal peduncle (v. absence of dorsolateral stripe or, if present, spanning more than half caudal‐peduncle length); premaxillary teeth longer than dentary teeth (v. dentary teeth longer); sexually mature adult males having well‐developed odontodes on the sides of the head and a broader snout (v. adult males lacking well‐developed hypertrophied odontodes or, if present, rostrum is same width as females' or immature males'); by having the ventral portion of the rostrum conspicuously darker than ventral surface of the body (v. rostrum light, with same colour as ventral portion of body, except in Sturisoma barbatum); by lacking the lateral process of the sphenotic (v. lateral process of sphenotic well‐developed, except in Sturisoma tenuirostre); a dark spot on the first three branched pectoral‐fin rays (v. brown spot absent, except in S. barbatum); and the frontal bone contributing less than half of dorsal border of the orbital ridge (v. extensive participation of the frontal, except in Sturisoma guentheri). Furthermore, the new species has 18–20 plates in the median series, which differentiates it from Sturisoma rostratum (21–22), and Sturisoma monopelte (21); and 14–15 coalescent plates, which differentiates it from S. tenuirostre (16–17). It is further differentiated from Sturisoma brevirostre by presence of an enlarged rostrum (v. rostrum not enlarged). A discussion regarding status of the type series and geographic distribution of Sturisoma rostratum is offered, and an identification key for all Sturisoma species is presented.     

A new viviparous acoel Childia vivipara sp. nov. with observations on the developing embryos, sperm ultrastructure, body wall and stylet musculatures

A free‐living viviparous acoel, Childia vivipara sp. nov., from the Gullmar fjord of the Swedish coast is described. The new species is assigned to the taxon Childia based on histological, ultrastructural and molecular sequence similarities. All available molecular markers (18S rRNA, 28S rRNA and histone H3) and several morphological characters, obtained using transmission electron microscopy and confocal scanning laser microscopy of whole mount specimen stained with TRITC‐labelled phalloidin, support the placement of C. vivipara in the taxon Childia. Childia vivipara and other Childia species share the following morphological synapomorphies: well‐developed copulatory organs built of tightly packed stylet needles, proximal part of the stylet inserted into the seminal vesicle, reversed body‐wall musculature, absence of ventral diagonal muscles, presence of dorsal diagonal muscles, and presence of ventral straight longitudinal muscles between frontal pore and mouth, 9 + 1 sperm axoneme structure, six distal sperm cytoplasmic microtubules, and extensive overlap of axonemes and nucleus. The new species can be easily distinguished from other Childia species by its viviparous mode of reproduction and single curved stylet. Observations on late embryonic development based on the oldest developing embryos are discussed.     

A giant crocodylomorph from the Upper Triassic of New Mexico

A new genus and species of giant crocodylomorph from the Upper Triassic of New Mexico is described.Redondavenator quayensis n. gen. et n. sp. (Crocodylomorpha: Sphenosuchia) has a very long posterior process of the premaxilla that fits between the nasal and the maxilla, and a long postglenoid process on the coracoid. These synapomorphies place it within the Crocodylomorpha.Redondavenator also has a System of grooves and pits that cover the anterior portions of the maxillae, the entire premaxillae, and the anterior part of the nasal. Possible foramina among the network of grooves and pits on the anterior portion of the skull may represent a rudimentary sensory System that is common to many extinct and ail extant crocodilians. Its exact phylogenetic position could not be determined from the preserved material, but key characters suggest a phylogenetic position near the base of Sphenosuchia.      

Segmentation and fusion on the midline: Basibranchial homologies in cypriniform fishes

The development and homologies of the median elements of the ventral hyoid and branchial arches of Cypriniformes have been unclear. We compared the developmental morphology of this region across five species (Cycleptus elongatus, Luxilus zonatus, Danio rerio, Devario auropurpureus, and Cobitis striata), representing three of five major clades of cypriniforms. The development of basibranchial 1 is similar in catostomids and cyprinids, where a single, elongate, basihyal + anterior copula divides into separate elements. A gap develops between the posterior end of the basihyal cartilage and the anterior copula in catostomids but in cyprinids (Luxiluszonatus, Danio rerio, and Devarioauropurpureus) there is little separation and the basihyal and basibranchial 1 may grow close together or retain a cartilaginous connection (Danio rerio, several outgroups). In loaches and Gyrinocheilus, the gap posterior to the basihyal has been alternately interpreted as either the absence or posterior displacement of basibranchial 1. Uniquely among examined species, in Cobitis striata, the basihyal cartilage and anterior copula form as separate cartilages and remain distinct throughout development with a prominent gap between the basihyal and most anterior basibranchial, which we interpret as loss of basibranchial 1. In the posterior region associated with branchial arches 4 and 5, all examined species except Danio rerio, which has only a basibranchial 4 cartilage, have separate basibranchial 4 and 5 cartilages in early ontogeny. Basibranchials 4 and 5 remain separate in Cycleptus elongatus, Devario auropurpurea, and Cobitis striata, but fuse in Luxilus zonatus to form a posterior copula. The orientation of basibranchial 4 and 5 cartilages in Cobitis striata is similar to catostomids and cyprinids. The most posterior median element in the branchial arches, the post‐ceratobranchial cartilage, generally forms as a separate cartilage in catostomids but in Cobitis striata is connected with basibranchial 5 cartilage from earliest appearance. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.     

Monophyly and taxonomy of the Neotropical seasonal killifish genus Leptolebias (Teleostei: Aplocheiloidei: Rivulidae), with the description of a new genus

A phylogenetic analysis based on morphological characters indicates that Leptolebias Myers, 1952, a genus of small killifishes highly threatened with extinction, from Brazil, is paraphyletic. As a consequence, Leptolebias is restricted in this study to a well‐supported clade that includes Leptolebias marmoratus (Ladiges, 1934), Leptolebias splendens (Myers, 1942), Leptolebias opalescens (Myers, 1942), and Leptolebias citrinipinnis ( Costa, Lacerda & Tanizaki, 1988 ), from the coastal plains of Rio de Janeiro, and Leptolebias aureoguttatus ( Cruz, 1974 ) (herein redescribed, and for which a lectotype is designated) and Leptolebias itanhaensis sp. nov. , from the coastal plains of São Paulo and Paraná, in southern Brazil.Leptolebias is diagnosed by three synapomorphies: a caudal fin that is longer than deep, a single anterior supraorbital neuromast, and dark pigmentation that does not extend to the distal portion of the dorsal fin in males. A key is provided for the identification of species of Leptolebias. Three species formerly placed in Leptolebias, Leptolebias minimus (Myers, 1942), Leptolebias fractifasciatus ( Costa, 1988 ), and Leptolebias cruzi ( Costa, 1988 ), are transferred to Notholebias gen. nov. , which is hypothesized to be the sister group to the clade comprising Leptolebias, Campellolebias Vaz‐Ferreira & Sierra, 1974, and Cynopoecilus Regan, 1912. Notholebias gen nov. is diagnosed by two synapomorphies: a narrow basihyal and the presence of iridescent bars on the caudal fin in males; and three features interpreted as plesiomorphic, but not occurring in Leptolebias, Campellolebias, or Cynopoecilus, the presence of dermosphenotic, well‐developed contact organs on the pectoral fin in males, and an opercular region with red bars in males. ‘Leptolebias’leitaoi, a species from Bahia, in north‐eastern Brazil, is considered as having an uncertain phylogenetic position, as all known preserved material is presently lost, and the species may be extinct. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153 , 147–160.     

The Phylogeny of the Myrmecophagidae (Mammalia, Xenarthra, Vermilingua) and the Relationship of Eurotamandua to the Vermilingua

A cladistic investigation of the phylogenetic relationships among the three extant anteater genera and the three undoubted extinct myrmecophagid genera is performed based upon osteological characteristics of the skull and postcranial skeleton. One hundred seven discrete morphological characters are analyzed using the computer program PAUP. Characters are polarized via comparison to the successive xenarthran outgroups Tardigrada (represented by the living sloth Bradypus) and Cingulata (represented by the recent armadillos Dasypus and Euphractus). The analysis results in a single most-parsimonious tree (TL = 190, CI = 0.699, RI = 0.713). The tree corroborates the monophyly of the subfamilies Cyclopinae and Myrmecophaginae, the former including the extant Cyclopes and the Pliocene genus Palaeomyrmidon. Within the Myrmecophaginae the Miocene genus Protamandua is the sister taxon to a clade including the remaining three genera. The recent Tamandua is in turn the sister taxon to the extant Myrmecophaga plus the Pliocene genus Neotamandua. Contrary to the suggestions of recent authors, weak support is provided for the taxonomic distinctiveness of the latter genus from the recent Myrmecophaga. The monophyly of the Myrmecophagidae is supported by 15 unequivocal synapomorphies. The monophyly of the Cyclopinae and Myrmecophaginae is supported by 3 and 13 unambiguous synapomorphies, respectively. The enigmatic Eocene genus Eurotamandua, from the Messel fauna of Germany, is coded for the 107 morphological characters above and included in two subsequent PAUP analyses. The palaeanodont Metacheiromys is also added to these two analyses as a nonxenarthran outgroup to test for the possibility that Eurotamandua lies outside the Xenarthra. In the first analysis, Eurotamandua is constrained a priori to membership in the Vermilingua. The single most-parsimonious tree (TL = 224, CI = 0.618) that results places Eurotamandua as the sister group to the remaining anteater genera, contra Storch and Habersetzer's (1991) assignment of Eurotamandua to the vermilinguan subfamily Myrmecophaginae. Eurotamandua shares six unequivocal synapomorphies with other anteaters, including the absence of teeth and the presence of a lateral tuberosity on the fifth metatarsal. The remaining vermilinguans are united by 11 unequivocal synapomorphies, plus an additional 10 ambiguous synapomorphies. In the second analysis, the position of Eurotamandua is unconstrained. The resulting single most-parsimonious tree (TL = 219, CI = 0.632) places Eurotamandua outside Vermilingua as the sister group to the Pilosa (Vermilingua plus Bradypus). The monophyly of this node is supported by four unambiguous synapomorphies in the unconstrained analysis. Further manipulation of this second analysis shows that placement of Eurotamandua as the sister group to the Xenarthra or to the Palaeanodonta adds three steps to the shortest tree but is more parsimonious than its placement as a sister group to the Vermilingua is the previous analysis. The addition of pangolins to the analysis does little to alter the major phylogenetic conclusions of the study. The allocation of Eurotamandua to the Xenarthra, but as a sister group to the Pilosa, is a novel arrangement which leaves open the biogeographic question of how a xenarthran reached Western Europe during the Eocene.     

Monophyly of Euaesthetinae (Coleoptera: Staphylinidae): phylogenetic evidence from adults and larvae,review of austral genera,and new larval descriptions

Abstract We develop a morphological dataset for the rove beetle subfamily Euaesthetinae comprising 167 morphological characters (135 adult and 32 larval) scored from 30 terminal taxa including 25 ingroup terminals (from subfamilies Euaesthetinae and Steninae) and five outgroups. Four maximum parsimony analyses using different sets of terminals and character sets were run to test the monophyly of (1) Euaesthetinae, (2) Steninae, (3) Euaesthetinae + Steninae, (4) euaesthetine tribes Austroesthetini, Alzadaesthetini, Euaesthetini, Fenderiini and Stenaesthetini, and (5) the ten currently known austral endemic genera together. Analyses of adult and larval character sets separately and in combination recovered the monophyly of Euaesthetinae, Steninae, and both subfamilies together, with strong support. Analysis of 13 ingroup terminals for which complete data were available suggests that monophyly of Euaesthetinae is supported by 19 synapomorphies (13 adult, six larval), of Steninae by 23 synapomorphies (14 adult, nine larval), and of both subfamilies together by 24 synapomorphies (21 adult, three larval). Within Euaesthetinae, only the tribe Stenaesthetini was recovered as monophyletic based on adult characters, and in no analyses were the ten austral endemic genera recovered as a monophyletic group. Phylogenetic relationships among euaesthetine genera were weakly supported, although analyses including adult characters supported monophyly of Octavius and Protopristus separately, and of Octavius + Protopristus, Austroesthetus + Chilioesthetus and Edaphus + Euaesthetus. Steninae may include a third genus comprising two undescribed species probably possessing a ‘stick–capture’ method of prey capture, similar to that in Stenus. These two species formed a strongly supported clade recovered as the sister group of Stenus based on adult characters. Diagnoses and a key to adults are provided for the 15 euaesthetine genera currently known from the austral region (Australia, New Zealand, South Africa and southern South America). Euaesthetine larvae previously were known only for Euaesthetus, and we describe the larvae of nine more genera and provide the first larval identification key for genera of Euaesthetinae.     

?Kenyaichthyidae fam. nov. and ?Kenyaichthys gen. nov. – First Record of a Fossil Aplocheiloid Killifish (Teleostei,Cyprinodontiformes)

The extant Cyprinodontiformes (killifishes) with their two suborders Cyprinodontoidei and Aplocheiloidei represent a diverse and well-studied group of fishes. However, their fossil record is comparatively sparse and has so far yielded members of the Cyprinodontoidei only. Here we report on cyprinodontiform fossils from the upper Miocene Lukeino Formation in the Tugen Hills of the Central Rift Valley of Kenya, which represent the first fossil record of an aplocheiloid killifish. A total of 169 specimens - mostly extraordinarily well preserved - and a sample of ten extant cyprinodontiform species were studied on the basis of morphometrics, meristics and osteology. A phylogenetic analysis using PAUP was also conducted for the fossils. Both the osteological data and the phylogenetic analysis provide strong evidence for the assignment of the fossils to the Aplocheiloidei, and justify the definition of the new family †Kenyaichthyidae, the new genus †Kenyaichthys and the new species †K. kipkechi sp. nov. The phylogenetic analysis unexpectedly places †Kenyaichthys gen. nov. in a sister relationship to the Rivulidae (a purely Neotropical group), a probable explanation might be lack of available synapomorphies for the Rivulidae, Nothobranchiidae and Aplocheilidae. The specimens of †K. kipkechi sp. nov. show several polymorphic characters and large overlap in meristic traits, which justifies their interpretation as a species flock in statu nascendi. Patterns of variation in neural and haemal spine dimensions in the caudal vertebrae of †Kenyaichthys gen. nov. and the extant species studied indicate that some previously suggested synapomorphies of the Cyprinodontoidei and Aplocheiloidei need to be revised.     

Patterns of population differentiation in annual killifishes from the Paraná–Uruguay–La Plata Basin: the role of vicariance and dispersal

Aim To elucidate the role of vicariance versus dispersal at the microevolutionary scale in annual killifish populations belonging to the Austrolebias bellottii species complex (Rivulidae). Within this complex, A. bellottii and A. apaii have low vagility and occur widely within the study area, making them excellent models for testing biogeographic hypotheses of differentiation. Location South America, in the Paraná–Uruguay–La Plata river basin. Methods Molecular data and morphometric analyses were used to reconstruct the phylogeographic history and morphological variation of 24 populations of two taxa of the A. bellottii species complex. Phylogenetic analyses using maximum likelihood (ML) and Bayesian inference (BI) model‐based methods, estimates of clade divergence times implemented in beast , non‐metric multidimensional scaling, analysis of molecular variance results, and morphological analyses elucidated the role of vicariance versus dispersal hypotheses in population differentiation in the aforementioned river basin. Results In the A. bellottii species complex from the Paraná–Uruguay–La Plata river basin, past allopatric fragmentation from vicariance events seems to be the most plausible scenario for diversification since the Late Miocene and more recently since the Plio‐Pleistocene. The Plio‐Pleistocene vicariance produced the differentiation of three major clades in A. bellottii populations. One clade from the eastern Uruguay River drainage was separated from another in western Uruguay and the Paraná–La Plata River drainages. A later vicariance event split populations to the south (lower Paraná–La Plata Basin) and north (middle Paraná) of the western Paraná River drainage. However, our results do not exclude the possibility of dispersal events among A. bellottii populations from both the Uruguay and Paraná river drainages, which could occur in these river basins during hypothesized connectivity cycles of the Late Pliocene and Pleistocene. Main conclusions Past allopatric fragmentation caused by different vicariance events seems to be the main driver of diversification in the A. bellottii species complex since the Plio‐Pleistocene. However, the current molecular data suggest that populations from both drainages of the Paraná–Uruguay rivers may have experienced cycles of connectivity during the Pleistocene, perhaps including multiple vicariance or dispersal events from populations located in the western lower Uruguay River drainage, which encompassed climatic and geological changes in the Paraná–Uruguay–La Plata Basin.     

How many marmoset (Primates: Cebidae: Callitrichinae) genera are there? A phylogenetic analysis based on multiple morphological systems

The marmosets, tribe Callitrichini, are the most speciose clade in the subfamily Callitrichinae, containing 21 species. However, there is no consensus among molecular and morphological systematists as to how many genera should be recognized for the group. To test the morphological support for the alternative generic classifications, this study presents a comprehensive phylogenetic analysis. It is the first such analysis to include all 21 species and employ continuous and discrete osteological, pelage and tegument, karyological and vocal characters. This dataset was combined with nucleotide sequences from two mitochondrial and four nuclear regions. Separate analyses showed that, among morphological datasets, osteological characters were best at solving relationships at more inclusive levels, whilst pelage characters were most informative at the interspecific level. This suggests the presence of different transformation rates for the two character sets. When a single most parsimonious tree was obtained using the 83‐character matrix, three main clades were identified, supporting the division of the marmosets into three genera: Callithrix, Cebuella and Mico. The total evidence analysis that included an additional 3481 molecular characters corroborated most of the morphology‐based clades and also supported a three‐genus classification of the marmosets. This is the first morphological study to support an Amazonian marmoset clade (Cebuella + Mico), which is also strongly supported in exclusively molecular phylogenies, and to synonimize Callibella under Mico.