Zachary S Randall

University of Florida | UF · Department of Natural History

The taxonomy of the Parachela–Oxygaster–Macrochirichthys clade of Xenocyprididae has been confused since the original descriptions of Parachela oxygastroides and Parachela hypophthalmus in the mid‐19th century. The confusion seems attributable to the substantial intraspecific variation in color and other morphological characteristics of species of...

The impact of preserved museum specimens is transforming and increasing by three-dimensional (3D) imaging that creates high-fidelity online digital specimens. Through examples from the openVertebrate (oVert) Thematic Collections Network, we describe how we created a digitization community dedicated to the shared vision of making 3D data of specimen...

Garra panitvongi, new species, is described from the Ataran River drainage, Salween River basin, of southeastern Myanmar and western Thailand. It is the sixth species of Garra known from the Salween River basin and is readily distinguished from all congeners by the red-orange color of the body and caudal fin, and a pointed proboscis with a blue str...

A review of the six recognized species of Pseudohomaloptera is provided. Counts in the original description of Pseudohomaloptera sexmaculata Fowler (1934) were incorrect and led to confusion in identifying populations of Pseudohomaloptera in mainland Southeast Asia, and the species is re‐described. The validity of Homaloptera septemmaculata Fowler...

We report on the discovery of a wild, reproducing population of Channa aurolineata (Pisces: Channidae) in west-central Florida (USA), and first documented occurrence of snakeheads in the Gulf Coast region. Channa aurolineata is a large, predatory fish of the bullseye snakehead “Marulius group” species complex from Asia. Adult and juvenile specimens...

Balitorid loaches are a family of fishes that exhibit morphological adaptations to living in fast flowing water, including an enlarged sacral rib that creates a ‘hip’-like skeletal connection between the pelvis and the axial skeleton. The presence of this sacral rib, the robustness of which varies across the family, is hypothesized to facilitate te...

Three species of spotted groupers in the subfamily Epinephelinae are known from the western Atlantic, Cephalopholis cruentata (Lacepède 1802), Epinephelus adscensionis (Osbeck 1765), and E. guttatus (Linnaeus 1758). Our research into the historical sources of the names revealed a confused history and the unclear identities of the taxa, with both C....

Herein, we present the complete mitochondrial genome of the Jaguar Loach, Yasuhikotakia splendida. The sequence was determined from an aquarium specimen using a next-generation sequencing approach. The annotated Y. splendida mitogenome was 16,695 bp in length and contained 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes...

The rheophilic hillstream loaches (Balitoridae) of South and Southeast Asia possess a range of pelvic girdle morphologies, which may be attributed to adaptations for locomotion against rapidly flowing water. Specifically, the connectivity of the pelvic plate (basipterygium) to the vertebral column via a sacral rib, and the relative size and shape o...

Garra surinbinnani, new species, is described from the Mae Khlong basin of western Thailand. It is the fourth species of Garra known from the basin and occurs syntopically with the other three species in fast-flowing rocky riffles. Within the Mae Khlong basin, it is most similar to G. fuliginosa from which it differs most obviously in having a bilo...

In 2017 NSF funded “oVert (openVertebrate): Open Exploration of Vertebrate Diversity in 3D,” which is the first Thematic Collections Network devoted entirely to vertebrate morphological specimens. The primary goal of oVert is to generate and serve high-resolution digital three-dimensional data for internal anatomy across vertebrate diversity. oVert...

This book is a comprehensive identification guide to the 222 species of fishes in Florida’s fresh waters. Each species is presented with color photographs, key characteristics for identification, comparisons to similar species, habitat descriptions, and dot distribution maps. Florida's unique mix of species includes some of the world's favorite sp...

Acantopsis (Cobitidae) is revised based on analysis of morphological and molecular data. Four of the six available names, A. dialuzona, A. spectabilis, A. octoactinotos, and A. thiemmedhi, are valid, and three new species, A. rungthipae, A. dinema, and A. ioa, are described. All species are described morphologically, distributions are mapped, and r...

The genus Balitoropsis Smith 1945 consists of two species, B. zollingeri (Bleeker 1853) and B. ophiolepis (Bleeker 1853). Homaloptera maxinae Fowler 1937, Balitoropsis bartschi Smith 1945, and Homaloptera nigra Alfred 1969 are junior synonyms of B. zollingeri. Balitoropsis zollingeri has been reported from Thailand, Laos, Cambodia, Malay Peninsula,...

Homaloptera van Hasselt 1823 as treated historically exhibits substantial morphological diversity and is paraphyletic based on both morphological and molecular data. The morphological diversity and phylogenetic relationships of Homaloptera, Homalopteroides Fowler 1905, Homalopterula Fowler 1940, and Balitoropsis Smith 1945, are elucidated. Pseudoho...

Homalopteroides avii, new species, is described from the Rajang River basin, Sarawak, Malaysian Borneo. It is distinguished from all other species of Homalopteroides by a wider gape of 28.5-33.3% HL vs. 22.3-24.2% for H. wassinkii, 20.0-28.4% for H. modestus, 19.1% for H. rupicola, 19.1-27.3% for H. smithi, 20.0-23.2% for H. stephensoni, 20.226.9%...

Tree-building with diverse data maximizes explanatory power. Application of molecular clock models to ancient speciation events risks a bias against detection of fast radiations subsequent to the Cretaceous-Paleogene (K-Pg) event. Contrary to Springer et al., post–K-Pg placental diversification does not require “virus-like” substitution rates. Even...

To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated wit...

Recent fieldwork has revealed the presence of six species of Schistura McClelland 1838 in the Mae Khlong basin in south-western Thailand. These include S. sexcauda (Fowler 1937), S. balteata (Rendahl 1948), S. mahnerti Kottelat 1990, the recently described S. aurantiaca Plongsesthee et al. 2011 and S. tenebrosa Kangrang et al. 2012, and a newly dis...

The genus Homalopteroides Fowler 1905 is resurrected and distinguished from the genus Homaloptera van Hasselt 1823 based on a combination of characters including a unique mouth morphology, dorsal-fin origin over pelvic fin, ≤ 60 lateralline scales, and ≤ 30 predorsal scales. Species included in Homalopteroides are H. wassinkii (Bleeker 1853), H. mo...