Sound production by fishes has been recognized for millennia, but is typically regarded as comparatively rare and thus yet to be integrated into broader concepts of vertebrate evolution. We map the most comprehensive dataset of sound production yet assembled onto a family-level phylogeny of ray-finned fishes (Actinopterygii), a clade containing more than 34,000 extant species. Family-, rather than species-, level analyses allowed broad investigation of sound production mostly based on illustrations of acoustic recordings and morphological specializations (82%) strongly indicative of sound production along with qualitative descriptions (18%), and a conservative estimate of the distribution and ancestry of a character that is likely more widespread than currently known. Compilation of sonic-related morphological characters shows 60 families exhibiting muscles coupled to swim bladder vibration and 39 families that employ movement of skeletal parts against each other, i.e., stridulation. Eighteen of these families, mostly catfishes (13), include individual species exhibiting both mechanisms. The results show that families with soniferous species contain nearly two-thirds of actinopterygian species, including a clade originating circa 155 Ma, and that sound production has independently evolved approximately 33 times within Actinopterygii. Despite the uncertainties of presence-only data records and incomplete evidence of absence, under-sampling species, and assuming family-level conservation of sound production, sensitivity analyses show that these patterns of shared ancestry are robust. In aggregate, these findings offer a new perspective on the ancestry and convergent evolution of sound production among actinopterygians, a clade representing more than half of extant vertebrate species.

The taxonomic status and phylogenetic relationships of the Deepwater Goby, Ponticola bathybius, an endemic species in the southern Caspian Sea, which were previously unknown, are examined here. Deepwater Goby samples were collected from three southern Caspian Sea localities (southwest, mid-south, and southeast), and phylogenetic analyses were conducted using mitochondrial cytochrome b (cyt b) and S7 nuclear gene sequences with maximum likelihood and Bayesian approaches. Additionally, the Deepwater Goby's population genetic structure and demographic history were evaluated for cyt b. Results were highly congruent, providing strong support for inclusion of the Deepwater Goby in the genus Neogobius (tribe: Neogobiini), from its previous placement in the genus Ponticola (tribe: Ponticolini). AMOVA analyses showed significant differences between western and eastern sampling localities (P < 0.05) of Deepwater Goby, with moderate F_ST (0.095) divergence. The haplotype network appeared star-like in formation, with no apparent genetic structure, indicating high connectivity and gene flow, and supporting a single continuous population. Since the Deepwater Goby exhibits low mobility after settlement, except for some migration between deeper and shallower waters, gene flow primarily occurs through spread of pre-settlement post-larvae via regional water currents. Mismatch distribution and neutrality tests both indicated that the Deepwater Goby likely underwent a recent demographic expansion in the southern Caspian Sea, estimated at ∼247 kya during the Pleistocene epoch, coinciding with similar expansions of other Caspian Sea taxa.

The Gopher Tortoise is a keystone species and a species of conservation concern in the southeastern United States, but the biology of tortoises at the extreme southeastern limit of the range is poorly understood. We examined physical characteristics and habitat associations of Gopher Tortoise burrows in pine rockland natural preserves in the highly urbanized Miami-Dade County (Florida, USA). We measured width, depth, and orientation of burrows at two sites. We compared a suite of 11 habitat features (e.g., canopy cover, understory density, ground cover, soil depth, and soil compaction) at random points and at Gopher Tortoise burrows in each of the two sites. Burrow widths were similar between sites and included burrows of both adults and juveniles—evidence that both populations are reproducing. Burrows were very short (most <2 m) compared to burrow lengths reported from other sites (>4 m), likely because soil depth is very shallow in extreme south Florida. We used multidimensional scaling and analysis of similarity to detect differences in habitat variables among sites, among point types (random points and burrows), and between active and inactive burrows. Low leaf litter cover, high grass cover, low canopy cover, and deep soil were among the major variables associated with all burrows and active burrows. The habitat associations of the burrows were similar to studies from other areas, yet the short burrows and association with the deepest available soils appear to be a strong response to the unique geology of pine rockland habitats. We discuss vegetative associations of Gopher Tortoises in the context of management in urban natural areas and implications for protection of Gopher Tortoises at the southern limit of their geographic range.

We describe a new arboreal alligator lizard species in the genus Abronia from the Sierra de Zongolica in west-central Veracruz, Mexico. The new species is presently known only from the vicinity of the type locality. It is diagnosable from all congeners by the following combination of characters: one occipital scale, two primary temporal scales contacting the postocular series, moderately protuberant posterolateral head scales, lack of protuberant or spine-like supra-auricular scales, 30–34 transverse dorsal scale rows, dorsal scales on the flanks arranged in slightly oblique longitudinal rows relative to the ventrolateral fold, and lateralmost ventral scale row unexpanded relative to the adjacent medial row. The new species occurs sympatrically with Abronia graminea, but genomic data assign it to the oaxacae group as the sister species of A. oaxacae, a finding that is corroborated by morphological evidence. We briefly discuss the regional biogeography of arboreal Abronia and comment on the Sierra de Zongolica as a complex transitional area of high species richness and conservation importance.

Lithobates areolatus (Crawfish Frog) is an imperiled amphibian, unique among ranid frogs due to its obligate use of crayfish burrows, highly terrestrial behavior, and reliance on open-canopy habitats within the central USA. Currently listed as near-threatened by the IUCN, and as state endangered, threatened, or of greatest conservation need in every state where it occurs, L. areolatus could potentially serve as an umbrella species for biodiversity conservation in the region. However, few studies have sought to identify site characteristics most strongly associated with the occupancy of L. areolatus or rigorously assessed the status of populations across core areas of the species' range in Arkansas, Oklahoma, and Kansas. Within northwest Arkansas, we used an occupancy-modeling framework to 1) determine landscape characteristics that could serve as predictors of the occupancy of L. areolatus and 2) assess the status of current and historical populations. We completed 405 time-constrained auditory surveys across 81 potential and historical breeding wetlands of L. areolatus over two breeding seasons (March–April 2016 and 2017). Estimated occupancy and detection were 0.26 and 0.32, respectively. We did not detect L. areolatus at 37.5% (6/16) of historic breeding wetlands during our study, indicating these populations are likely extirpated. Occupancy probability was strongly related to density of prairie mounds within 1 km of breeding wetlands and was weakly related to clay and chert/gravel loam soil. Our results suggest that: 1) L. areolatus is widespread throughout northwest Arkansas but is threatened by the expanding human population, 2) detection probability is high under optimal conditions (cool temperatures [9–12°C] and recent rain [within 24 hr]), and 3) prairie mound density is a useful proxy for upland habitat quality, likely reflecting minimal soil disturbance and presence of crayfish burrows.

An illustrated description of the juvenile (9.7 mm head length) of Pyramodon lindas from the Indian Ocean is given for the first time. The specimen is compared with the previously described vexillifer larvae of P. ventralis and P. punctatus. The juvenile of P. lindas is clearly distinguished from the other species of Pyramodon by the number of pectoral-fin rays and its pigmentation pattern. This is the first record of this species in the western Indian Ocean north of Madagascar.

Many species retain the physiological capacity to hybridize over long periods of evolutionary time. Hybridization has been reported for sharks and may be the reason for uncertainty regarding phylogenetic relationships within the genus Mustelus. Because of similar life histories and morphologies, limited genetic divergence (both nuclear and mitochondrial DNA), and the degree of uncertainty regarding their phylogenetic relationship, 32 allozyme loci were used to determine the levels of genetic diversity for the Grey Smoothhound, Mustelus californicus, and the Brown Smoothhound, M. henlei, and to detect species-specific nuclear markers capable of determining the existence of hybridization within northeastern Pacific Mustelus. Tissue extracts from 26 adult M. henlei collected from Santa Catalina Island, California and 17 M. californicus collected from Marina Del Rey, California were subjected to starch gel electrophoresis. Gene products of the 32 loci were resolved for all specimens of both species. All 32 loci were monoallelic in M. californicus, whereas four polyallelic loci, three diallelic and one triallelic, were resolved in M. henlei. Nine of the 32 loci exhibited complete allelic divergence between the two species (i.e., no shared alleles) and can serve as diagnostic markers to reveal potential F₁ and F₂ hybrids.

Parotocinclus hardmani, new species, is described as a new hypoptopomatine from tributaries of the Potaro River, Essequibo River basin, Potaro-Siparuni, Guyana. The new species is distinguished from congeners in northeastern and southeastern coastal rivers of Brazil by having the canal cheek plate elongated posteriorly on the ventral surface of the head and in contact with the cleithrum. It is diagnosed from species of Parotocinclus from the Amazon, Orinoco, and Guianas watersheds by uniquely having a conspicuously elongated, conical urogenital papilla which is twice the size of the anal tube and 3–4 times larger than in congeners, by having the central abdominal area mostly devoid of plates, by mature males lacking a dermal flap on the dorsal surface of the first pelvic-fin ray, and, except for P. halbothi, by having a rudimentary adipose fin adnate to the dorsal plates, without a membrane. The new species is believed to form a clade with P. collinsae and P. halbothi, with which it shares accessory teeth on both premaxilla and dentary, the odontodes on the first pelvic-fin ray aligned with the main ray axis, not bent and pointing mesially, the lack of a triangular dark spot at the anterior base of the dorsal fin, and the lack of a Y-shaped light mark from the snout tip to each nostril.

Marking or tagging salamanders increases efficiencies in the operations and management of captive populations and facilitates techniques for monitoring demographics of wild populations. Tags facilitate monitoring of longitudinal data for individual animals such as age or estimated age, growth, reproduction, and health. We evaluated three different tagging methods on Texas Blind, San Marcos, and Comal Springs Salamanders to determine success of each as a long-term marker of individual animals. For this study, we selected visible implant elastomer (VIE), visible implant alphanumeric tags (VIA), and passive integrated transponders (PIT). Of these, only VIE tagging has been evaluated in San Marcos Salamanders; none have been evaluated for use in the other two salamander species studied; and comparison studies among these tags for fully aquatic salamander species have not been performed. These tag types were selected for their effectiveness with other salamander species, ability to be quickly and easily identified tank-side, minimal negative effects on organisms, and perceived ease of implanting the tags. The VIE tags were retained by all species and had high readability scores. However, the issues of tag breakage and deterioration should be considered when using VIE tags. VIA tags were rejected in all but one San Marcos Salamander and all Comal Springs Salamanders, but 90% of Texas Blind Salamanders retained them. PIT tags were not tested on San Marcos, Comal Springs, and smaller Texas Blind Salamanders due to size of tag and low retention rate in larger salamanders. Of the tags evaluated in this study, VIE was the most effective in terms of retention, readability, and ease of insertion.

Climate change is one of the greatest threats to species across the globe, but the threats to tropical animals have largely been overlooked. Tropical high elevation species are distinctly at risk as they will be unable to disperse to habitats with favorable temperatures in the future. Twenty percent of all lizard species may be faced with extinction. Proctoporus unsaacae and P. sucullucu are two thermoconforming lizard species native to the Central Andes mountains where their habitats are predicted to rise over 3°C within the 21^st century. Because these species do not thermoregulate behaviorally, we predicted that they would have narrow temperature tolerances and would be vulnerable to climate warming. We collected lizards of these species in Peru and tested their critical thermal maxima (CT_max) by slowly heating them until they were unable to maintain normal bodily functions, measured by muscular spasms. Surprisingly, we found that the species have high thermal tolerance with P. unsaacae averaging 38.2°C CT_max and P. sucullucu averaging 39.4°C. The difference between CT_max and field active body temperatures for both species exceeded 20°C. Based on our results, increased environmental temperature will not directly cause these species to suffer death or activity restriction. We posit that these species of Proctoporus and the few other truly eurythermic lizard species may be particularly well suited to surviving global temperature increases. Although global warming will continue to cause the decline and extinction of species worldwide, more research is needed on species with unusual ecologies before making sweeping statements about the dire fate of reptiles.

Aquatic turtles represent important biotic components of freshwater ecosystems. The Pecos River watershed is inhabited by six freshwater turtle species, including the widespread Trachemys scripta (Red-eared Slider) and a species of conservation concern, Pseudemys gorzugi (Rio Grande Cooter). Here, we assessed isotopic niche widths of Rio Grande Cooter and niche overlap where it co-occurs with Red-eared Slider in the Pecos River tributaries, New Mexico, USA. We used carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope analyses of two different tissue types: blood and claw. Our results showed niche partitioning among different populations of P. gorzugi and among sex classes within a population. At the sites where both species occur, we documented niche overlap, especially for δ¹⁵N values. Stable isotopes showed similar ellipse area overlap (SEA_B) of T. scripta and P. gorzugi among populations (∼20‰²), but little to no overlap of standard ellipse areas for small sample sizes (SEA_C). The distribution of prey items in the diets of P. gorzugi and T. scripta revealed the differences in resource selection. We observed that differences in the diets of P. gorzugi among populations correspond to local resource availability, suggesting opportunistic foraging behavior of P. gorzugi. Our study aids in understanding the ecology and natural history of P. gorzugi, one of the least studied freshwater turtles in the USA. Moreover, our study provides insights to interspecific relations of T. scripta in their native range.

For more than 100 years, biologists, ecologists, and biogeographers recognized six species of Apogon in the eastern Pacific Ocean. Re-examining this taxonomy, we find that Apogon guadalupensis is a synonym of A. atricaudus based on morphological and molecular data. A redescription of A. atricaudus is provided, and a new northern occurrence for A. atradorsatus is reported.

Arctozenus risso, the White Barracudina, is a member of the Paralepididae, the largest family within the order Aulopiformes. In recent years the systematics of the family and the order has advanced significantly due to morphological, molecular, and holistic studies, which has led to a general agreement of their relationships. Some phylogenetic discrepancies remain in particular among the species-rich paralepidids, based on the difficulties in obtaining comprehensive taxon samples as well as the lack of morphological studies. We found an enlarged autopalatine following the enlarged ethmoid region of the skull. We identified a large ossification that covers the dorsal surface of the basibranchial copula as a basibranchial tooth plate and identified a second smaller tooth plate associated with basibranchial 4. However, the most peculiar structures are dorsal ligament ossifications that are associated with the anterior and posterior dorsal-fin pterygiophores, and supraneural 2. We hope the description of the skeletal anatomy of A. risso will help to solve some of the open questions of the phylogenetic relationships of the paralepidids and aulopiforms.

The Columbia Spotted Frog (Rana luteiventris; CSF) is widely distributed across northwestern North America; however, declines in the southernmost populations, including those in Utah, have resulted in the consideration of this species for protection under the Endangered Species Act. In 1998, a conservation agreement and strategy for Utah's populations of CSF was developed and identified needed conservation actions, including range expansion. We repatriated CSF larvae during 2008–2010 from an extant population in the Provo River into Beaver Creek, a beaver-dominated stream, in the Weber River, a watershed where contemporary surveys indicate CSF have likely been extirpated. In 2011, CSF breeding was first observed in the repatriated population when 11 egg masses were documented in four depositional areas. After ten years of monitoring egg mass numbers, we consider the repatriation a success as this population continues to grow and expand with a high of 54 egg masses (2019) within ten depositional areas (2020). High quality habitat and the large number of CSF larvae transplanted likely attributed to the success of this repatriation. We used 1–2 day old CSF larvae (Gosner life stage 20–21) as the repatriation life stage that we believed would be the most likely to prevent the spread of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) from the known chytrid fungus positive donor site in the Provo River. Genetic testing of a robust sample (n = 59) of CSF tadpoles across the repatriation site in 2020 did not detect the presence of Bd, potentially indicating that we did not move Bd through the repatriation. Additional replicates would be required beyond this single experiment, however, to better determine if our transplant techniques are effective at preventing the spread of Bd.

South America's Chocó, part of the North Andean Pacific Slopes–Rio Atrato ecoregion, is a biodiversity hotspot with many disjunct rivers, yet phylogeographic and population genetic studies of the Chocó's aquatic species are scarce. Rhoadsia is a Chocó endemic freshwater fish genus with two recognized species: R. minor from the upper Esmeraldas River drainage and R. altipinna from the lower Guayas River drainage, Ecuador. Little is known about the evolutionary history of Rhoadsia, and due to morphological similarities, the validity of the two nominal species has been questioned. We conducted a phylogeographic study using two mitochondrial genes and 12 microsatellite markers to examine the evolutionary history of Rhoadsia and the validity of its two species. Samples collected in drainages throughout western Ecuador from sea level to 1260 m.a.s.l. were included, as were samples of species in the closely related genera Parastremma and Carlana from Colombia and Central America. Phylogenetic analysis of the mtDNA markers confirmed the reciprocal monophyly of a northern and southern clade, and the presence of mitochondrial haplotypes of both clades in the northern Guayas basin. Structure analysis with the microsatellite markers pointed to introgression at the border between the species ranges as the likely cause of the mixing of mitochondrial haplotypes in the northern Guayas. Bayesian analysis of the microsatellite data revealed the existence of ten populations throughout western Ecuador, divided into three main geographically segregated groups. Group I coincided with the northern distribution of R. minor, while groups II and III seemed to represent geographic subgroups of R. altipinna in the Guayas and southern coastal drainages. Patterns of genetic divergence and diversity support the recognition of multiple evolutionarily significant units within both species and allowed reevaluation of previously reported freshwater biogeographic zones in the Ecuadorian Chocó. This study provides a baseline for future studies examining freshwater biogeographical patterns throughout the Ecuadorian Chocó, as well as a phylogeographic framework to examine the genetic basis of adaptation of morphologically divergent populations of Rhoadsia inhabiting Andean mountain streams in the region.

Authors' note.—H Geoffrey Moser was one of the most influential larval-fish biologists of the past century. He was perhaps best known to ASIH members as the coeditor and motivating force behind the first ASIH Special Publication, Ontogeny and Systematics of Fishes. His other accomplishments included an extensive body of publications on larval fishes, with descriptions of development in almost 50 families and as editor of one of the most comprehensive regional identification guides for the California Current (relevant for much of the eastern Pacific and elsewhere). He co-taught courses in larval-fish identification that trained a generation of ichthyologists in that discipline. Many of those scientists have passed that skill on to younger students, continuing his legacy to the present. In addition, he was a talented illustrator and a poet. Geoff, as he was known to his colleagues and friends, passed away unexpectedly at the age of 83 on September 30, 2021. He was interviewed for this Historical Perspective by internet during the COVID-19 pandemic at his home in Bozeman, Montana, in April, 2021 by Eric Hilton and Bruce Mundy. He also provided most of the photographs. The interview was completed through questions and answers exchanged by email. Geoff was shown all of the drafts of this account. He actively contributed to it until the day before his death and approved its content.