Amanda K. Pinion

Rakthamichthys anchi, a new species of phreatobitic synbranchid is described from wells in a small village in Goalpara District, Assam, Northeast India. It is distinguished from the northeastern Indian R. rongsaw, and the Western Ghats congeners R. roseni, R. digressus, and R. mumba by absence of lateral-line canal pores in the frontal. From R. roseni, R. digressus, and R. mumba, it is further distinguished by more preanal vertebrae (90–100 vs. 76–88 in) and from R. indicus by more vertebrae (159 vs.162–169). It is also distinguished from the Western Ghats species by an uncorrected p-distance of ~15–20% in the barcoding gene. From R. roseni, the only Western Ghats species for which detailed osteological information is available, R. anchi is distinguished by several anatomical characters. The discovery of R. anchi from wells in the same village in which Gitchak nakana Britz et al. was recently described highlights the presence of a formerly unknown and highly dynamic subterranean habitat: the groundwater aquifers in alluvial deposits in northeast India.

Combined analyses of molecular and morphological data support a revised classification of Notropis stramineus comprising five distinct evolutionary lineages, two for which names are available, Notropis stramineus (Cope, 1865) and N. missuriensis (Cope, 1871), herein redescribed, and three for which no names are available, here formally described as new species. Four of these clades comprise a species complex, here termed the N. stramineus species complex, while these four clades, in addition to N. procne , N. topeka , N. chihuahua and the fifth clade form a monophyletic group here termed the N. stramineus species group. Notropis lucifer sp. nov. , sister taxon of N. chihuahua , is distributed in the Colorado River and Rio Grande basins of Texas (USA), where it is distributed in the Devils River, and presumably also in Pinto Creek; based on distribution, populations in tributaries of the Rio Grande in Mexico are tentatively also assigned to this species. Notropis lucifer sp. nov. can be distinguished from other members of the N. stramineus species group primarily by coloration in life and pigmentation patterns which are still visible after preservation. Notropis oblitus sp. nov. is found in several Gulf Slope streams in Texas, including the upper reaches of Nueces, San Antonio, and Guadalupe River basins, though likely absent from the Colorado River basin. This species can be distinguished from other members by head shape, eye size and pigmentation patterns. Notropis multicorniculatus sp. nov. is found in the western portions of the Arkansas, Canadian and Red River basins in parts of Texas, Oklahoma, and Kansas, and likely also Arkansas and Colorado, as well as the Pecos River (New Mexico), where it is likely non-native. This species can be distinguished from other members of the species complex by comparatively larger and more abundant tubercles in males and differences in body shape. Comments are provided regarding the genus Miniellus , which has been recently suggested to comprise 21 species, including N. stramineus .

Larval attachment organs (LAOs) are unicellular or multicellular organs that enable the larvae of many actinopterygian fishes to adhere to a substrate before yolk-sac absorption and the free-swimming stage. Bowfins (Amiiformes) exhibit a sizable LAO on the snout, which was first described in the late 19th and early 20th centuries. In this study, we document the LAO of Amia ocellicauda (Richardson, 1836) using a combination of scanning electron microscopy (SEM) and light microscopy, and histochemistry. We examined material representing three stages with SEM ranging in size from 5.8 to 11.2 mm in notochord length and one stage histochemically. We compare the LAO of A. ocellicauda to that of the lepisosteid Atractosteus tropicus Gill, 1863 and show that although the LAOs of A. ocellicauda and A. tropicus are both super-organs, the two differ in the ultrastructure of the entire organ. A. ocellicauda possesses two distinct lobes, with the organs arranged on the periphery with none in the middle, whereas A. tropicus also possesses two lobes, but with the organs scattered evenly across the super-organ. The individual organs of A. ocellicauda possess adhesive cells set deep to support cells with the adhesive substance released through a pore, whereas A. tropicus possesses both support cells and adhesive cells sitting at a similar level, with the adhesive substance released directly onto the surface of the organ. We additionally provide a table summarizing vertebrate genera in which attachment organs have been documented and discuss the implications of our study for hypotheses of the homology of attachment organs in the Holostei.

The native range of Ophichthys cuchia includes part of Bangladesh, Bhutan, India, Myanmar, and Nepal. Ophichthys cuchia has also been collected within six states in the USA (Louisiana, Maryland, Michigan, New Jersey, New York, and Pennsylvania) and an established invasive population exists in New Orleans (Louisiana). We provide the first record of O. cuchia from Texas and the second report of an established non-native population in the USA based on 26 museum vouchered specimens collected from a series of urban ponds within the Houston metro area (Fort Bend Co.).

The eyes of teleostean fishes typically exhibit two ossifications, the anterior and posterior sclerotics, both associated with the scleral cartilage. The West African Denticle herring Denticeps clupeoides has three scleral ossifications, including the typical two associated with the scleral cartilage (anterior and posterior sclerotic) and a third ossification (Di Dario's ossicle), spatially separated from the scleral cartilage and located within the anteromedial wall of the sclera. The medial rectus muscle inserts on the medial surface of Di Dario's ossicle, suggesting that this third sclerotic may play a role in forward rotation of the eye in this surface feeding fish.

Larval attachment organs are unicellular or multicellular organs that allow larvae to adhere to a substrate prior to yolk‐sac absorption and the free‐swimming stage. We document the larval attachment organ of Atractosteus tropicus, the Tropical gar, using a combination of scanning electron microscopy and light microscopy. We show that the larval attachment organ of A. tropicus is a super‐organ surrounded by a wall and containing at its center many smaller multicellular organ units, each comprised of attachment and support cells. Attachment cells are secretory and house large vacuoles filled with a glycoprotein. At hatching, the super‐organ is well‐developed and occupies almost the entire anteroventral surface of the head. During subsequent development, the smaller individual units begin to regress, until at 6 days post hatching the super‐organ and its individual units are no longer visible.

Dajaus monticola (Bancroft, 1834) is an amphidromous species of mugilid known from South and Central America and the islands of the Caribbean but is rarely collected in Gulf coast states of the United States. Two new records of D. monticola collected from the Gulf of Mexico (Brazoria Co.) and the Brazos River (Washington Co.) are reported from Texas. The rare occurrence of D. monticola in Texas is discussed and diagnostic characters used to distinguish this species from other mugilids found in Texas are reevaluated.