Taxonomic status of the Hispaniolan Cichlidae

http://deepblue.lib.umich.edu/bitstream/2027.42/57173/1/OP737.pd

Genomic, ecological, and morphological approaches to investigating species limits: A case study in modern taxonomy from Tropical Eastern Pacific surgeonfishes

A wide variety of species are distinguished by slight color variations. However, molecular analyses have repeatedly demonstrated that coloration does not always correspond to distinct evolutionary histories between closely related groups, suggesting that this trait is labile and can be misleading for species identification. In the present study, we analyze the evolutionary history of sister species of Prionurus surgeonfishes in the Tropical Eastern Pacific (TEP), which are distinguished by the presence or absence of dark spots on their body. We examined the species limits in this system using comparative specimen-based approaches, a mitochondrial gene (COI), more than 800 nuclear loci (Ultraconserved Elements), and abiotic niche comparisons. The results indicate there is a complete overlap of meristic counts and morphometric measurements between the two species. Further, we detected multiple individuals with intermediate spotting patterns suggesting that coloration is not diagnostic. Mitochondrial data recovered a single main haplotype shared between the species and all locations resulting in a complete lack of structure (phi(ST) = 0). Genomic analyses also suggest low levels of genetic differentiation (F-ST = 0.013), and no alternatively fixed SNPs were detected between the two phenotypes. Furthermore, niche comparisons could not reject niche equivalency or similarity between the species. These results suggest that these two phenotypes are conspecific and widely distributed in the TEP. Here, we recognize Prionurus punctatus Gill 1862 as a junior subjective synonym of P. laticlavius (Valenciennes 1846). The underlying causes of phenotypic variation in this species are unknown. However, this system gives insight into general evolutionary dynamics within the TEP

Testing conjectures about morphological diversity in cichlids of Lakes Malawi and Tanganyika

The morphological diversity of Malawi and Tanganyika cichlids has often been qualitatively described, but rarely have hypotheses based on these descriptions been tested empirically. Using landmark based geometric morphometrics, shapes are analyzed independent of other aspects of the body form (e.g., size). The estimation of shape disparity, the quantitative measure of the variance of these raw shapes, can then be applied in order to objectively test hypotheses about morphological diversity. The shape disparity within and between different groups is explored as well as how it is partitioned within the cichlid body. Tanganyika cichlids are found to have significantly greater shape disparity than Malawi cichlids. Ectodini is found to have significantly greater shape disparity than other Great Lake tribes. Piscivorous cichlids are significantly more disparate in shape than cichlids with other diets, and the shape disparity of the cranial region was significantly greater than that of the postcranial region. © 2005 by the American Society of Ichtbyologists and Herpetologists

Systematics and historical biogeography of Greater Antillean Cichlidae

A molecular phylogenetic analysis recovers a pattern consistent with a drift vicariance scenario for the origin of Greater Antillean cichlids. This phylogeny, based on mitochondrial and nuclear genes, reveals that clades on different geographic regions diverged concurrently with the geological separation of these areas. Middle America was initially colonized by South American cichlids in the Cretaceous, most probably through the Cretaceous Island Arc. The separation of Greater Antillean cichlids and their mainland Middle American relatives was caused by a drift vicariance event that took place when the islands became separated from Yucatan in the Eocene. Greater Antillean cichlids are monophyletic and do not have close South American relatives. Therefore, the alternative hypothesis that these cichlids migrated via an Oligocene landbridge from South America is falsified. A marine dispersal hypothesis is not employed because the drift vicariance hypothesis is better able to explain the biogeographic patterns, both temporal and phylogenetic. © 2006 Elsevier Inc. All rights reserved

Tripodfish (Aulopiformes: Bathypterois) locomotion and landing behaviour from video observation at bathypelagic depths in the Campos Basin of Brazil

A video observation of a deep-sea tripodfish (Aulopiformes: Bathypterois) taken from a remotely-operated vehicle at a depth of 1443 m in the Campos Basin, Brazil is analysed for swimming and landing movements. The observed specimen is identified here as Bathypteroisgrallator, and this record is the first video observation of a tripodfish exhibiting periodic swimming followed by landing in a resting position on deep-sea substrate which we interpret as ‘bathypteroiform’ movement, a locomotive mode unique to taxa within Bathypterois. This observation describes the functional role of the fins associated with landing, including independent movements of the elongated fin ray elements. The specimen is observed to display subcarangiform body and/or caudal fin movement while swimming in a periodic state. Prior to landing, the specimen is observed to raise its elongated caudal fin element parallel to the body, a behaviour that has not been described previously. Following contact of the elongated pelvic fin elements with the deep-sea floor, the elongated caudal fin element is independently lowered, completing the tripod stance typically observed. © 2011 Taylor & Francis Group, LLC

A new species of ponyfish (Teleostei: Leiognathidae: Photoplagios) from the Philippines

A new species of ponyfish in the genus Photoplagios is described from material collected in the Philippines. Photoplagios laterofenestra, new species, is distinguished from congeners by the presence in males of an expansive translucent flank patch in the shape of a cornucopia. Additionally, both sexes of the new species can be distinguished from congeners by body shape, pigmentation pattern on the upper flank, and length of the second dorsal-fin spine. © 2007 by the American Society of Ichthyologists and Herpetologists

The identity of catfishes identified as Mystus cavasius (Hamilton, 1822) (Teleostei: Bagridae), with a description of a new species from Myanmar

The identity of South Asian riverine bagrid catfishes usually referred to as Mystus cavasius (Hamilton, 1822) is reviewed. Three species comprise what is currently understood as M. cavasius: M. cavasius s. str. from northern India, M. seengtee from southern India and a new species, M. falcarius, from the Salween and Irrawaddy river drainages in Myanmar and the shorter river drainages in southern Myanmar. Mystus seengtee is resurrected from synonymy with M. cavasius and both species are redescribed. The three species differ from other congeners with a long-based adipose fin in having a combination of a black spot in front of the dorsal-spine base, a dark humeral mark, a body without distinct midlateral stripes, very long maxillary barbels reaching to caudal-fin base, dorsal spine short and feebly serrate, tall dorsal fin, and 13-29 gill rakers. These species differ from each other in dorsal fin shape, shape of the predorsal profile, coloration, and number of rakers on the first gill arch. Copyright © 2005 Magnolia Press