James W. Orr

Evolutionary history of anglerfishes (Teleostei: Lophiiformes): a mitogenomic perspective

BackgroundThe teleost order Lophiiformes, commonly known as the anglerfishes, contains a diverse array of marine fishes, ranging from benthic shallow-water dwellers to highly modified deep-sea midwater species. They comprise 321 living species placed in 68 genera, 18 families and 5 suborders, but approximately half of the species diversity is occupied by deep-sea ceratioids distributed among 11 families. The evolutionary origins of such remarkable habitat and species diversity, however, remain elusive because of the lack of fresh material for a majority of the deep-sea ceratioids and incompleteness of the fossil record across all of the Lophiiformes. To obtain a comprehensive picture of the phylogeny and evolutionary history of the anglerfishes, we assembled whole mitochondrial genome (mitogenome) sequences from 39 lophiiforms (33 newly determined during this study) representing all five suborders and 17 of the 18 families. Sequences of 77 higher teleosts including the 39 lophiiform sequences were unambiguously aligned and subjected to phylogenetic analysis and divergence time estimation.ResultsPartitioned maximum likelihood analysis confidently recovered monophyly for all of the higher taxa (including the order itself) with the exception of the Thaumatichthyidae (Lasiognathus was deeply nested within the Oneirodidae). The mitogenomic trees strongly support the most basal and an apical position of the Lophioidei and a clade comprising Chaunacoidei + Ceratioidei, respectively, although alternative phylogenetic positions of the remaining two suborders (Antennarioidei and Ogcocephaloidei) with respect to the above two lineages are statistically indistinguishable. While morphology-based intra-subordinal relationships for relatively shallow, benthic dwellers (Lophioidei, Antennarioidei, Ogcocephaloidei, Chaunacoidei) are either congruent with or statistically indistinguishable from the present mitogenomic tree, those of the principally deep-sea midwater dwellers (Ceratioidei) cannot be reconciled with the molecular phylogeny. A relaxed molecular-clock Bayesian analysis of the divergence times suggests that all of the subordinal diversifications have occurred during a relatively short time period between 100 and 130 Myr ago (early to mid Cretaceous).ConclusionsThe mitogenomic analyses revealed previously unappreciated phylogenetic relationships among the lophiiform suborders and ceratioid familes. Although the latter relationships cannot be reconciled with the earlier hypotheses based on morphology, we found that simple exclusion of the reductive or simplified characters can alleviate some of the conflict. The acquisition of novel features, such as male dwarfism, bioluminescent lures, and unique reproductive modes allowed the deep-sea ceratioids to diversify rapidly in a largely unexploited, food-poor bathypelagic zone (200-2000 m depth) relative to the other lophiiforms occurring in shallow coastal areas.

Genetic and morphological evidence for cryptic diversity in the Careproctus rastrinus species complex (Liparidae) of the North Pacific

The molecular phylogeny of the Careproctus rastrinus species complex is presented on the basis of sequence variations in the 16S rRNA and cytochrome b genes (1,447 base pairs) of mitochondrial DNA using specimens collected from across the North Pacific and its marginal seas, including the Sea of Japan, the Pacific coast of Japan, the Sea of Okhotsk, the Bering Sea, the Gulf of Alaska, and the Arctic Ocean. Gene flow and migration between geographic regions is apparently strictly restricted in the C. rastrinus species complex, as this phylogeny revealed nine genetically diverged groups in the C. rastrinus species complex, most of which corresponded well with major geographic regions. Most of the groups were different in terms of morphological characters. Five nominal species have been considered to be members of the complex and have been variously recognized as being valid or as synonyms of C. rastrinus, but the present genetic and morphological differences suggested that the C. rastrinus species complex represents far more divergence. Such cryptic diversity of the C. rastrinus species complex defined by geographic regions may be related to their low dispersal ability, because they bear large demersal eggs. The genetic divergence suggested that colder climates from the late Pliocene and the isolation of marginal seas during the Pleistocene may have driven the divergence of the C. rastrinus species complex.

Bathyraja mariposa, a new species of skate (Rajidae : Arhynchobatinae) from the Aleutian Islands

Abstract A new species of the skate genus Bathyraja, Bathyraja mariposa, is described from the Aleutian Islands and its geographic and bathymetric range documented. Bathyraja mariposa is similar to Bathyraja violacea and Rhinoraja taranetzi in its moderate maximum size and absence of thorns on the disc. However, it can be clearly distinguished from B. violacea by its distinctive color pattern, uniform covering of fine denticles, and clasper morphology. It can be distinguished from R. taranetzi and other similar western North Pacific species by the lack of a pseudosiphon on the clasper as well as by differences in various morphometric and meristic characters.

Molecular systematics of the skate subgenus Arctoraja (Bathyraja: Rajidae) and support for an undescribed species, the leopard skate, with comments on the phylogenetics of Bathyraja

Sequence variability in the cytochrome c oxidase I (COI) gene from 226 samples of the species previously considered Bathyraja parmifera (Rajidae) revealed three distinct haplotypes, one of which represents an undescribed species, the leopard skate. Further genetic examination of four closely related North Pacific and Bering Sea skate species, Bathyraja parmifera, B. simoterus, B. smirnovi, and the leopard skate in comparison with 19 related species indicates that together these four species comprise the subgenus Arctoraja. Phylogenetic analysis suggests that Arctoraja is monophyletic, but that the genus Bathyraja may be paraphyletic due to the phylogenetic position of Rhinoraja.

Two New Variegated Snailfishes of the Genus Careproctus (Teleostei: Scorpaeniformes: Liparidae) from the Aleutian Islands, Alaska

Abstract Two new species of snailfishes are described on the basis of 99 individuals collected from the Aleutian Islands during resource assessment surveys conducted by the National Marine Fisheries Service. Both are distinguished from all known species of Careproctus by a variegated red, white, and gray body coloration, an unlobed dorsal fin, protruding snout, the absence of distal pectoral radials at the base of 8–12 ventral rays, and counts of median-fin rays and vertebrae. Careproctus comus, new species, is distinguished from Careproctus faunus, new species, by having a greater number of caudal vertebrae and median-fin rays, as well as a narrower interorbital width, shorter maxilla, shorter snout, shorter connection of anal-fin membrane to caudal fin, and more slender caudal-fin base. Careproctus comus ranges from west of Attu Island, on Stalemate Bank, to the eastern Aleutian Islands, near Unalaska Island. Careproctus faunus ranges from Adak Island in the central Aleutians to just east of Unalaska Island. Both species are found at depths of approximately 150–400 m. Among other liparids of the North Pacific, the new species are superficially similar to Temnocora candida, from which both can be readily distinguished on the basis of their unlobed dorsal fin and higher counts of median-fin rays and vertebrae.

Eggs and late-stage embryos of Allocareproctus unangas (family Liparidae) from the Aleutian Islands

Four unusual masses of adhesive fish eggs surrounding limbs of the octocoral Primnoa sp. were collected in Seguam Pass in the Aleutian Island Archipelago at a depth of 397 m. The eggs contained embryos in the flexion stage of development. When dissected and cleared and stained, counts of dorsal and anal fin rays and vertebrae allowed identification of the eggs as those of Allocareproctus unangas Orr and Busby, a newly described snailfish species. This is first report of snailfishes of the genus Allocareproctus, and of liparids other than those in the genus Liparis, spawning outside of lithodid crabs.

Lopholiparis flerxi: A New Genus and Species of Snailfish (Scorpaeniformes: Liparidae) from the Aleutian Islands, Alaska

Abstract A new genus and species of the scorpaeniform family Liparidae, Lopholiparis flerxi, is described from the central Aleutian Islands, Alaska. The new genus differs from all known liparid genera in having supraorbital ridges, produced by enlarged and heavily ossified frontals and sphenotics, and enlarged opercles. It also has seven spinous dorsal-fin rays, the anteriormost six forming a distinct lobe; an elliptical pupil; and low dorsal- and anal-fin ray counts. It is most similar to Temnocora candida, which also possesses an anterior spinous dorsal-fin lobe and an elliptical pupil.

Snailfishes of the Careproctus rastrinus complex (Liparidae): redescriptions of seven species in the North Pacific Ocean region, with the description of a new species from the Beaufort Sea

Herein we review and recognize as valid all previously described species of the Careproctus rastrinus complex based on morphological evidence, provide diagnoses and descriptions of all species, describe a new species from the Beaufort Sea, and address the misapplication of several names throughout the area. In particular, the name C. rastrinus is restricted to populations of the western Pacific and is known conclusively only from the Sea of Okhotsk. Careproctus acanthodes, from the Sea of Japan and Sea of Okhotsk, and C. pellucidus, from the Pacific Ocean side of northern Japan, are resurrected from synonymy with C. rastrinus. Populations of the eastern Pacific previously routinely identified as C. rastrinus are recognized under two names: C. scottae, a name that is applied to deeper water Bering Sea, Aleutian Islands, and eastern Pacific populations having a postorbital pore, and Careproctus phasma, applied to shallow water populations of the Bering Sea and Gulf of Alaska lacking a postorbital pore. Although we consider Careproctus spectrum valid, the species has been routinely misidentified and is presently known only from the type series. Careproctus lerikimae is a new species described from the Beaufort Sea, diagnosed from other species of the C. rastrinus complex by the absence of the postorbital pore and higher median fin and vertebral counts.

Range Extensions and Significant Distributional Records for Eighty-Two Species of Fishes in Alaskan Marine Waters

Abstract Increased fisheries survey effort over the last decade by the US National Marine Fisheries Service (NMFS), Alaska Fisheries Science Center (AFSC), through its Resource Assessment and Conservation Engineering (RACE) and Fisheries Monitoring and Analysis (FMA) Divisions, has allowed biologists to collect voucher specimens and document the geographic distribution of marine fishes in Alaskan waters, including commercially important species as well as those more rarely encountered. A vouchering system allows for confirmation of field identifications, and access to specimens is ensured by their deposition at the University of Washington Burke Museum Fish Collection (UWFC). Herein we report the 1st Alaskan records for 10 species, the 1st Bering Sea records for 10 species, the 2nd or 3rd Alaskan records for 13 species, significant range extensions in the Bering Sea for 17 species, 9 species in the Aleutian Islands, 11 species in the Gulf of Alaska, and 8 species for which new records fill the gap in distribution across the North Pacific region. We also document specimens for 4 Alaska species previously cited in the literature without vouchers. A total of 83 species are discussed and photos are provided for 17 of the rarely encountered and poorly documented species.

Secondary contact in the Sea of Japan: the case of the Careproctus rastrinus species complex (Liparidae)

The Careproctus rastrinus species complex, widely known from the North Pacific, has been revealed recently to include nine genetically divergent groups on the basis of mitochondrial DNA (mtDNA) sequence variations. Herein we describe an AFLP analysis that focuses on three closely related groups in order to clarify the evolutionary history of the species complex in the Sea of Japan and off the Pacific coast of Japan. A principal coordinate analysis indicated the absence of nuclear divergence in two groups defined by mtDNA variations in the Sea of Japan, whereas another group from the Pacific coast of northern Japan was clearly distinct. This suggests extensive gene flow between two groups in the Sea of Japan as a result of secondary contact.