Kinorhynchs are microscopic invertebrates that are part of the meiofaunal community. Their diversity and distribution has been relatively unstudied in the Gulf of Mexico until the past few years. Past studies from Troy University have reported 32 species of kinorhynchs in the Gulf, from Texas to Florida. This study reports a re-sampling effort which focused on the Louisiana shelf, in an attempt to further understand the relationships between the shelf sediment and the kinorhynch diversity. For this work, sediment was sampled at 16 locations in 2015 using a multicorer. Kinorhynchs were isolated using centrifugation. Animal densities ranged from <1–33/10 cm², with an average of 12 animals/10 cm². A total of 345 animals were identified to the species level. Echinoderes bookhouti was the most abundant animal, which along with E. augustae, E. spinifurca, E. skipperae, and Leiocanthus cf. L. langi accounted for almost all the identifications. Additionally, we report four new species records for the Gulf of Mexico: Pycnophyes alexandroi, P. norenburgi,Antygomonas paulae, and Leiocanthus cf. L. corrugatus. These data reveal a multi-year trend with regard to dominant kinorhynch species within the Gulf of Mexico, and support an earlier study of Gulf kinorhynchs from 2013–2014. Multivariate analysis revealed that sediment locations with higher densities of kinorhynchs associated with higher levels of organic matter, and sediment locations with low densities associated with sandy sediment.

Fringe-lip tongue soles with three ocular-side lateral lines and different ocular-side color patterns were collected mainly at fish landing ports from east to south coastal regions of China. Specimens were divided into three groups: those with color patterns previously reported for Paraplagusia japonica (Temminck & Schlegel, 1846) called Color Pattern I (CPI) and Color Pattern II (CPII); and those, preliminarily identified as Paraplagusia sp., that featured a different color pattern (CPIII). CPI featured only pale ocelli superimposed on a greenish-brown or yellowish-brown background color; CPII featured only black spots superimposed on a brownish-black or grayish-brown background color; and CPIII featured both pale ocelli and black spots mixed over a yellowish-brown or brownish-black background color. Specimens with CPI pattern are smaller in body size (78.3–279.0 mm SL) compared to the lengths of specimens with the CPII (191.7–337.1 mm SL) and CPIII patterns (155.9–352.9 mm SL). To determine whether specimens with CPIII represent a species different from P. japonica, a series of morphological characters and two partial gene sequences (COI and RAG1) were analyzed. Analyses revealed that specimens with these three different color patterns overlapped in 27 morphological characters including nine meristic and 18 morphometric features. And, the K2P genetic distances of COI and RAG1 fragments were 0.000–0.007 and 0.000–0.006, respectively. This study confirms that fringe-lip tongue soles inhabiting coastal waters of China that possess three lateral lines, but have different ocular-side pigmentation patterns, belong to one species, P. japonica. These results also caution the use of pigment features as diagnostic characters to distinguish species of Paraplagusia. An updated redescription and synonymy for P. japonica, including summaries of variation in morphological characters and pigmentation, size at maturity, and geographical distribution are provided. Results of the present study will be helpful in better understanding the taxonomic significance of color patterns of cynoglossid flatfishes.

Cerion uva gouldi is described as a new subspecies to include only fossil and subfossil Cerion uva from Aruba. The name Cerion uva arubanumBaker, 1924 had previously been applied to all Cerion uva from Aruba, living and fossil. A recent molecular study has shown that Cerion uva arubanum, a taxon based on living type material from Aruba, is a synonym of Cerion uva uva (Linnaeus, 1758), with which it shares a preponderance of mitochondrial haplotypes. Cerion uva was widespread on Aruba during the Pleistocene, but became extinct on that island and was subsequently reintroduced from a population near Willemstad in eastern Curaçao by humans within the past 800 years. Earlier authors had recognized that fossil Cerion from Aruba differ in morphology from those living on the island today, with fossils being more similar to specimens from western Curaçao and Bonaire, while those living on Aruba today are most similar to Cerion uva uva from eastern Curaçao. Cerion uva gouldi may be distinguished from living populations of Cerion on Aruba on the basis of its cylindrical rather than ovate shell shape, its more closely spaced whorls, and its round aperture with a uniform rather than anteriorly expanded parietal rim.

Acropora prolifera is an ecologically distinctive western Atlantic reef-building coral that originates from hybridization and back-crossing between A. palmata and A. cervicornis. It has been suggested that A. prolifera might be a recent product of precipitous decline in the abundance of the two parent species, forcing hybridization where both it and its product might not otherwise be prevalent phenomena. We present evidence that A. prolifera has a fossil record dating back to at least the late Pleistocene, and that it was ecologically significant prior to the region-wide die-back of acroporid corals. These data, when taken collectively, reveal that hybridization in the Caribbean acroporids is historically rooted and not a recent artifact of changes in Caribbean reef ecology. It is becoming apparent that hybrid taxa likely play an important but underappreciated role in coral reef ecology and reef-building more generally. This is consistent with recent recognition that interspecific hybridization can drive evolutionary innovation and cladogenesis in animals as well as plants.

Heat-stressed New World vultures (Cathartidae) practice urohidrosis by excreting urate-rich urine on their tarsi and feet to decrease body temperature through evaporative cooling. Soft part colors are useful taxonomic characters in Cathartes, but dried urates obscure the color and pigmentation patterns of the tarsi and feet. I describe these characters in fresh specimens of Cathartes aura (Turkey Vulture), C. burrovianus (Lesser Yellow-headed Vulture), and C. melambrotus (Greater Yellow-headed Vulture) collected in Guyana. Species-specific differences in the melanic pigmentation of the tarsi and feet are revealed when urates are removed. The rosy-red intertarsal joints, which are normally unobscured by urates, may function in intraspecific signaling in all three species. The seasonality and geographic extent of urohidrosis in Cathartes are unknown.

Parasitic copepods of the genus Caligus infest the external tissues, mainly skin, of marine fishes. The objective of this study is to review the published literature about the distribution of the Caligus species that occur on the shores of mainland and insular Chile. Caligus species may be specialist or generalist in the selection of their host species. Hence, for each species of Caligus, we give a list of host fish species. The literature reports the presence of 12 species of Caligus. They may be cosmopolitan (C. bonito, C. flexispina, and C. productus), distributed in the Asia-Pacific region (C. lalandei, C. lichiae, and C. quadratus), restricted to Peru and Chile (C. cheilodactyli and C. debueni), or endemic to northern Chile (C. crusmae), southern Chile (C. rogercresseyi and C. teres), and Easter Island (C. fistulariae). Biogeographical topics are discussed in the present study.

Crangonyx hobbsiShoemaker, 1941, a variable stygobitic amphipod endemic to the Floridan aquifer, is redescribed from topotype material and populations adjacent to the type locality. In addition to the morphological redescription, genetic sequence data for sections of the nuclear 18S rDNA, 28S rDNA, and mitochondrial 16S rDNA are provided from populations located near the type locality.

Based on examination of porcellanid crabs from the Gulf of California, Mexico, deposited in the Colección Nacional de Crustáceos of the Instituto de Biología, Universidad Nacional Autónoma de México, we document Petrolisthes crenulatus, P. hirtispinosus and P. galapagensis as hosts of bopyrid isopods belonging to the genus Aporobopyrus for the first time. The new records increase to 42 the number of known hosts for these ectoparasites. Further, this report provides the first record of Aporobopyrus curtatus for the coasts of Mexico and the eastern Pacific, becoming the second species of the genus with an Amphiamerican distribution. The distribution ranges of A. bourdonis, A. muguensis and A. trilobatus are extended and morphological remarks and a key to the four bopyrid species are provided.

Speciation as a consequence of lineage reticulation is not uncommon. A taxonomic and nomenclatural issue arises when a putative hybrid becomes established and is, therefore, in contention for species recognition. While giving a unique name to a hybrid may be acceptable under the codes that govern nomenclature, this does not address issue of whether it constitutes a valid species. We suggest that there are two classes of hybrids. The first type of hybrid is episodic and not consistently present through time and, although such taxa may have a definition and name, we contend that they should not be considered species. The second type of hybrid is one that is indicative of a stable and continuing reticulation, where its definition and name identify and validate a reference point to enhance evolutionary explanation. We highlight that a conflict with the codes that govern functional nomenclature does not occur if the original author did not identify the taxon they were describing as a hybrid. In spatiotemporally stable populations, we argue against the retrospective invalidation of an existing species based on gained insights into putative hybrid ancestry. Instead, hybrid ancestry should be treated as bringing casual understating to the evolution of an organism. In contrast, arguing for hybrid ancestry under the current rules at the time of describing a taxon is seen as presenting an argument for invalidation if the rules are applied in the strictest sense. Furthermore, we argue that the collapse of infrafamiliar taxa based on hybrid ancestry reduces the explanatory potential of the nomenclature. We present a case study in which names now attributed to putative hybrids within Strombidae are considered for validation.

A new species of dorvilleid polychaete, Ophryotrocha urbis, is described from the Odaiba, Tokyo, Japan, at 3–5 m depth. The species belongs to O. lobifera group morphologically/phylogenetically and is distinguishable from other congeners by the following combined features: i) trifid margin of the dorsal anterior side of peristomium; ii) the presence of K-type maxillae; iii) the presence of palps; iv) presence of eyes. Individuals of the species were found only on dead animals, and thus, the species is possibly a scavenger. Partial mitochondrial cytochrome c oxidase subunit I gene sequences from the paratype of O. urbis is provided for reliable species identification in the future.