scholarly journals Revision of the ‘dragon-head’ cusk eels of the genus Porogadus (Teleostei: Ophidiidae), with description of eight new species and one new genus

Zootaxa ◽  
2021 ◽  
Vol 5029 (1) ◽  
pp. 1-96
Author(s):  
WERNER W. SCHWARZHANS ◽  
PETER R. MØLLER
Keyword(s):  
New Species ◽  
Sampling Bias ◽  
Eastern Pacific ◽  
Lateral Line System ◽  
Nominal Species ◽  
Line System ◽  
Discovery Research ◽  
Continental Slopes ◽  
Species Pairs ◽  
Being Moved

The ophidiid genus Porogadus occurs between 800 and 5300 m in the tropical and subtropical world oceans. Fifteen nominal species have been described since 1878 and most of them until 1902. The genus has been highlighted as needing revision in recent compilations about ophidiiforms and here we present the first comprehensive review. Twelve of the previously described species are here accepted as valid with two being moved to the newly established genus Tenuicephalus n. gen. that encompasses fishes differing from those of Porogadus in the extremely weak ossification, the stout head, absence of head spines and absence of the “triple” lateral line system considered typical for Porogadus and a reduced dentition. In addition, eight new species are described: Porogadus caboverdensis, P. dracocephalus, P. lacrimatus, P. mendax, P. solomonensis, P. turgidus, Tenuicephalus multitrabs and T. squamilabrus.                 The species of Porogadus show a distinctive depth segregation with the majority of species having a demersal bathyal life-style between 800 and 3500 m and other species being more or less exclusively restricted to abyssal depths below 3000 m. The biogeographic distribution pattern of bathyal groups shows putative species pairs in the Atlantic versus the eastern Pacific and a clear separation of eastern Pacific from Indo-West Pacific species. The geographic effects and timing are being discussed that may have led to this speciation events. Generally, we found widely distributed species that are found far away from continental masses and others restrained to continental slopes and sometimes exhibiting regionalism. In abyssal depth, the Cabo Verde and Canary basins off NW-Africa have yielded three exclusive species, but it is uncertain at this stage whether this could represent a sampling bias with this area being extensively sampled by the Discovery research vessel (BMNH) over the years from 1970–1998. Another instance of a potentially endemic abyssal species is that of Porogadus melanocephalus in the Bay of Bengal. The latter has been caught with 45 specimens in a single trawl, representing the highest number of Porogadus specimens collected in any trawl and indicating that these fishes may actually not be as rare as one might assume from the literature.  

Patterns of morphological diversity among and within arcid bivalve species pairs separated by the Isthmus of Panama

2001 ◽  
Vol 75 (3) ◽  
pp. 590-606 ◽  
Author(s):  
Peter B. Marko ◽  
Jeremy B. C. Jackson
Keyword(s):  
Morphological Variation ◽  
Fossil Record ◽  
Eastern Pacific ◽  
Nominal Species ◽  
Western Atlantic ◽  
Isthmus Of Panama ◽  
Species Pairs ◽  
Recent Species ◽  
Discriminant Analyses ◽  
Collection Sites

Geminate species are morphologically similar sister-species found on either side of the Isthmus of Panama. The existence of all geminates in the tropical Eastern Pacific ocean and the Caribbean Sea is most often explained by vicariance: closure of the Central American Seaway 3.1 to 3.5 Ma simultaneously isolated populations of species with amphi-American distributions. In this paper, we test the potential of morphological measurements for discriminating between Recent geminate species pairs from three genera (Arca, Arcopsis, and Barbatia) in the bivalve family Arcidae and examine the prospects for distinguishing nominal species in the fossil record. Fourteen morphological variables were used to characterize shell shape and multivariate methods were used to discriminate between five Recent species pairs. Collection sites were also used as a priori groups for discrimination to describe patterns of intraspecific morphological variation and to evaluate differences among samples from different geographic regions.On average, 84 percent of specimens within geminate pairs are classified correctly following five separate discriminant analyses with nominal species as the grouping variable. Although all but one arcid species pair are discriminated with high statistical significance, some collection sites within species are highly morphologically distinct. Overall, a large proportion of specimens from each collection locality (79 percent on average) can be classified correctly to site although no single site possessed a multivariate centroid that was significantly different from all other conspecific centroids. The distinctiveness of some collection sites, however, raises the possibility that some nominal species may harbor cryptic species, indicating the need for wider geographic surveys of both molecular and morphological variation within geminate species pairs.The eigenvalue coefficients derived from the Recent samples of one geminate pair (Arca mutabilis and A. imbricata) were used to assess the potential for identifying arcid species in the fossil record. Discriminant analyses of fossil Arca indicate that the forms that characterize Recent A. mutabilis and A. imbricata are present in the fossil record as far back as the Late Early Miocene, in the Cantaure Formation of Venezuela. Because a deep water connection between the Eastern Pacific and Western Atlantic existed until the Middle Miocene, the morphological differences associated with Recent A. mutabilis and A. imbricata likely existed well before the rising Isthmus affected ocean circulation patterns in tropical America. Therefore, despite great overall morphological similarity, these putative geminate species likely have a time of divergence that is at least four times older than final seaway closure. The geographic distribution of fossils also suggests that morphological forms associated with each Recent species had amphi-American distributions both before and after isthmus formation but are now geographically restricted to either side of the isthmus in the Recent fauna.

A new critically endangered slippery frog (Amphibia, Conrauidae, Conraua) from the Atewa Range, central Ghana

Zootaxa ◽  
2021 ◽  
Vol 4995 (1) ◽  
pp. 71-95
Author(s):  
KARLA NEIRA-SALAMEA ◽  
CALEB OFORI-BOATENG ◽  
N’GORAN G. KOUAMÉ ◽  
DAVID C. BLACKBURN ◽  
GABRIEL H. SEGNIAGBETO ◽  
...  
Keyword(s):  
New Species ◽  
Species Delimitation ◽  
Dominant Frequency ◽  
Biodiversity Hotspot ◽  
Morphological Evidence ◽  
Lateral Line System ◽  
Conservation Area ◽  
Forest Reserve ◽  
Line System ◽  
Molecular Phylogenetic

Forty-nine years after the last description of a slippery frog, we describe a seventh species of the genus Conraua. The new Conraua is endemic to the Atewa Range Forest Reserve, central Ghana, and is described based on genetic, bioacoustics, and morphological evidence. Recent molecular phylogenetic and species delimitation analyses support this population as distinct from nominotypical C. derooi in eastern Ghana and adjacent Togo. The new species is sister to C. derooi, from which it differs ~4% in the DNA sequence for mitochondrial ribosomal 16S. Genetic divergences in 16S to other species of Conraua range from 4–12%. The new species is distinguished morphologically from its congeners, including C. derooi, by the combination of the following characters: medium body size, robust limbs, lateral dermal fringing along edges of fingers, cream ventral color with brown mottling, the presence of a lateral line system, indistinct tympanum, the presence of inner, outer, and middle palmar tubercles, and two subarticular tubercles on fingers III and IV. We compare the advertisement calls of the new species with the calls from C. derooi and find that they differ by duration, frequency modulation, and dominant frequency. We discuss two potential drivers of speciation between C. derooi and the new species, including river barriers and fragmentation of previously more widespread forests in West Africa. Finally, we highlight the importance of the Atewa Range Forest Reserve as a critical conservation area within the Upper Guinean biodiversity hotspot.  

Schistura larketensis, a new cavernicolous fish (Teleostei: Nemacheilidae) from Meghalaya, Northeast India

Zootaxa ◽  
2017 ◽  
Vol 4353 (1) ◽  
pp. 89
Author(s):  
HRISHIKESH CHOUDHURY ◽  
D. KHLUR B. MUKHIM ◽  
SUDEM BASUMATARY ◽  
DEISAKEE P. WARBAH ◽  
DANDADHAR SARMA
Keyword(s):  
New Species ◽  
Lateral Line ◽  
Ventral Surface ◽  
Northeast India ◽  
Lateral Line System ◽  
Brahmaputra River ◽  
Line System ◽  
Limestone Cave ◽  
A New Species

Schistura larketensis, a new species of cavernicolous loach, is described from Khung, a limestone cave in Meghalaya, India. The species differs from Schistura papulifera, its only troglomorphic congener from northeast India, in having a smooth ventral surface of the head, the presence of a small cylindrical axillary pelvic lobe, and the presence of three pores in the supratemporal canal of the cephalic lateral-line system. Apart from these differences, the species can be immediately distinguished from all other species of Schistura from the Brahmaputra River and neighboring basins by the complete absence (or only vestigial presence) of eyes. 

Comparative morphology of the cottid genus Myoxocephalus based on meristic, morphometric, and other anatomical characters

1971 ◽  
Vol 49 (11) ◽  
pp. 1479-1496 ◽  
Author(s):  
Garry I. McT. Cowan
Keyword(s):  
Lateral Line ◽  
Gulf Of Alaska ◽  
Comparative Morphology ◽  
Distinct Species ◽  
Lateral Line System ◽  
Nominal Species ◽  
Meristic Characters ◽  
Important Species ◽  
Morphometric Characters ◽  
Line System

Specimens representing 15 nominal species of the genus Myoxocephalus were subjected to detailed comparative morphological study to determine some of the more important species characteristics and also those indicating potential for expressing phylogenetic progression.Analysis of seven meristic characters revealed that none of them is consistently sexually dependent. Geographic variation within the species indicated the presence of both latitudinal and longitudinal clines. No evolutionary group affinities were evident.The morphology of the cephalic lateral line system, lateral line ossicles, squamation, and olfactory rosettes were found to exhibit a high degree of specificity, especially the first three systems. With the exception of the lateral line ossicles all evidenced some potential as indicators of phylogeny.Analysis of 23 morphometric characters was accomplished by cluster analysis. The resultant clusters indicated heterogenous unnatural groupings.On the basis of these analyses well-defined species differences exist in most of the major morphological features. The nominal species M. scorpius (Linnaeus) includes three distinct species (Gulf of Alaska, Arctic–East coast, and European). In addition, the data indicate that the genus is probably composed of three basic evolutionary lines: the Holarctic–Atlantic, Bering Sea–Transpacific, and Asiatic.

A review of the Nemacheilinae genus Oreonectes Gunther with descriptions of two new species (Teleostei: Balitoridae)

Zootaxa ◽  
2008 ◽  
Vol 1729 (1) ◽  
pp. 23 ◽  
Author(s):  
LI-NA DU ◽  
XIAO-YONG CHEN ◽  
JUN-XING YANG
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Lateral Line ◽  
Related Species ◽  
Valid Species ◽  
Lateral Line System ◽  
Genital Papilla ◽  
Line System ◽  
Autonomous Region ◽  
Two New Species

The loach genus Oreonectes is reviewed in this study. Six valid species are recognized, including two new species. Oreonectes polystigmus sp. nov., and Oreonectes microphthalmus sp. nov. are described from the Guangxi Zhuang Autonomous Region, China. Among its congeners, O. polystigmus is most similar to O. platycephalus in morphology. It can be distinguished from all its congeners by an incomplete lateral line with 6–8 pores; a cephalic lateral-line system with 7 supraorbital and 4+7 infraorbital pores; sexual dimorphism (males have a genital papilla located immediately posterior of the anus, and the gonad is opened at the end of a fleshy prominence); and a body with many differently shaped spots. Oreonectes microphthalmus is most similar to O. furcocaudalis in morphology. It can be distinguished from all congeners by its degenerate eyes, which only have black pigment; a cephalic lateral-line system with 2+2 supratemporal, 7 supraorbital, 3+0 infraorbital and 8 preoperculomandibular pores; and an incomplete lateral line with 3 pores. A key to all valid Oreonectes species is provided. The validity of some related species is discussed. Nemacheilus liboensis, Oreonectes liboensis and Oreonectes translucens are all proved to be synonyms of Paracobitis longibarbatus, and Paracobitis longibarbatus is actually a species of Triplophysa.

A new species of Microglanis (Siluriformes, Pseudopimelodidae) from lower Rio Tocantins basin, Pará, Brazil, with description of superficial neuromasts and pores of lateral line system

Zootaxa ◽  
2010 ◽  
Vol 2632 (1) ◽  
pp. 53 ◽  
Author(s):  
WILLIAM BENEDITO GOTTO RUIZ ◽  
OSCAR AKIO SHIBATTA
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Lateral Line ◽  
Lateral Line System ◽  
Caudal Peduncle ◽  
Line System ◽  
A New Species ◽  
Predorsal Distance

Microglanis robustus, new species, is the first Microglanis to be described from the Rio Tocantins basin, Pará, Brazil, and differs from the congeners by the presence of a cordiform blotch in the nape, instead of a transverse light stripe; neuromasts of the superficial lines surrounded by melanophores; robust body with short snout, head and predorsal distance; and deep caudal peduncle. The mapping of superficial neuromasts and cephalic sensory canals evidenced intra and interespecific polymorphisms and, therefore, of little value for phylogenetic analysis within the genus.

A review of the Australian skate genus Pavoraja Whitley (Rajiformes: Arhynchobatidae)

Zootaxa ◽  
2008 ◽  
Vol 1812 (1) ◽  
pp. 1 ◽  
Author(s):  
PETER R. LAST ◽  
STEPHEN MALLICK ◽  
GORDON K. YEARSLEY
Keyword(s):  
New Species ◽  
Anatomical Structure ◽  
Colour Pattern ◽  
Nominal Species ◽  
Key To Species ◽  
Outer Continental Shelf ◽  
Additional Material ◽  
New Information ◽  
Species Pairs ◽  
Upper Slope

The Australian endemic skate genus Pavoraja Whitley, which contains six species including two valid nominal species (P. alleni and P. nitida) and four new species (P. arenaria sp. nov., P. mosaica sp. nov., P. pseudonitida sp. nov. and P. umbrosa sp. nov.), is redefined based on additional material. Members of the group occur primarily on the outer continental shelf and upper slope in both temperate and tropical Australian seas. The species are strongly partitioned geographically with smallto medium-scale ranges. Pavoraja arenaria is known to have a broad southern distribution but none is widespread in the Australian region. Only two species pairs, P. nitida and P. arenaria (off southern Australia), and P. mosaica and P. pseudonitida (off northeastern Australia), are known to be sympatric. New information is provided for the two nominal taxa, and the four new species are formally described and figured. Skeletal characteristics are described and illustrated, and a key to species is provided. Members of the genus differ primarily in colour pattern, squamation, morphometrics, meristics, and anatomical structure. The relationships of the genus Pavoraja to other arhynchobatid skates are discussed briefly.

Taxonomic and morphological revision of butterfly rays of the Gymnura micrura (Bloch & Schneider 1801) species complex, with the description of two new species (Myliobatiformes: Gymnuridae)

Zootaxa ◽  
2017 ◽  
Vol 4332 (1) ◽  
pp. 1 ◽  
Author(s):  
LEANDRO YOKOTA ◽  
MARCELO RODRIGUES DE CARVALHO
Keyword(s):  
New Species ◽  
Lateral Line ◽  
The Other ◽  
External Morphology ◽  
Valid Species ◽  
Lateral Line System ◽  
Western Atlantic ◽  
Line System ◽  
Lower Lip ◽  
Two New Species

An extensive taxonomic revision of Gymnura micrura based on external and internal morphology, and considering specimens from its entire geographical distribution in the Atlantic Ocean, is presented. Gymnura micrura is redescribed and a neotype is designated; its distributional range is limited to the Southwestern Atlantic. Two new species of butterfly rays are described: Gymnura lessae, sp. nov., occurring in the North and Central Western Atlantic, and Gymnura sereti, sp. nov., found in the Eastern Central Atlantic. The three species are morphologically very similar (with G. micrura most similar to G. lessae, sp. nov.) and cannot be distinguished based on the primary diagnostic characters typically utilized for butterfly rays. The dorsal color, smaller size and eventual presence of a dorsal fin in some males may be helpful to distinguish G. micrura, whereas the size and morphology of the clasper are the main external characters separating G. sereti, sp. nov., from the other two species, although the shape of disc (especially among adult males) and contour of the lower lip are also helpful. Despite the skeleton being conservative among the species, we found consistent variations that support the validity of the new species described. Due to similarity in external morphology these internal characters were fundamental to discriminate the new species. The scapulocoracoid was an important diagnostic skeletal structure, exhibiting a series of variations that separated the three species. Variations in the synarcual, outline of the dorsal cranial fontanelle, number and shape of mesopterygia, and small differences in the mandibular arches and pelvic girdle were useful to diagnose G. sereti, sp. nov. The contour of the hyomandibula was an important diagnostic character distinguishing G. lessae, sp. nov., from the other two species. Meristic data were also useful, with G. sereti, sp. nov., presenting a lower number of radials in the second element of the mesopterygium and a higher number of diplospondylous vertebrae. In contrast, G. lessae, sp. nov., presented a higher number of pectoral-fin radials. Subtle, but consistent differences, were also found in the design of the ventral lateral-line system. A Canonical Discriminant Analysis provides strong statistical support for the validity of the new species, significantly distinguishing the three species groupings (p < 0.00001). External morphology, ventral lateral-line system and skeleton are described and illustrated for all three valid species. 

Schistura papulifera, a new species of cave loach from Meghalaya, India (Teleostei: Balitoridae)

Zootaxa ◽  
2007 ◽  
Vol 1393 (1) ◽  
pp. 35 ◽  
Author(s):  
MAURICE KOTTELAT ◽  
DANIEL R. HARRIES ◽  
GRAHAM S. PROUDLOVE
Keyword(s):  
New Species ◽  
Lateral Line ◽  
Lower Half ◽  
Lateral Line System ◽  
Line System ◽  
A New Species

Schistura papulifera, new species, is described from a cave of the Synrang Pamiang system, Meghalaya State, India. It is distinguished from all other known species of Schistura in having the lower half of the head covered by small skin projections and 5 pores in the supratemporal canal of the cephalic lateral-line system. In addition, it has a white body and vestigial eyes. The closest epigean relative of S. papulifera has not yet been identified due to the lack of survey and usable data. The identity of the cave nemacheiline from Siju Cave is briefly discussed, but this remains inconclusive, again due to the lack of material and usable data.

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