Anal Fin Ray Counts Research Articles

Snailfishes of the genus Careproctus (Perciformes: Liparidae) with a reduced pelvic disk: three new species and new records from the western North Pacific with comments on their phenotypic diversity

A taxonomic review of the snailfish genus Careproctus (Liparidae) with a reduced pelvic disk—the Careproctus gilberti species group—from the western North Pacific recognized three new species from the southern Sea of Okhotsk, and confirmed the validity of Careproctus gilberti, Careproctus mederi, Careproctus ostentum, and Careproctus parvidiscus. One of the newly described species, Careproctus longibarbatus sp. nov., had been previously confused with C. mederi, but was readily distinguishable on the basis of counts of vertebrae (61–66 vs. 57–63), dorsal- (56–60 vs. 52–56) and anal-fin rays (50–54 vs. 47–52), as well as length of the pectoral fin lower lobe (extending past anus vs. not reaching anus) and color of the peritoneum (dark vs. pale with black dots). Careproctus barbatulus sp. nov. and Careproctus spinulosus sp. nov. were diagnosed by pectoral fin lower lobe length, anus position, and vertebral, and dorsal- and anal-fin ray counts. The validities of the three new species were also confirmed by mitochondrial sequence data. Careproctus mederi was redescribed based on specimens from the southern Sea of Okhotsk, representing the first Japanese, as well as southernmost record of the species. Furthermore, the full description of an unidentified Careproctus species, most similar to C. gilberti, from the Pacific coast of Hokkaido was provided. Significant morphological variation within the C. gilberti species group, possibly resulting from reproductive interference among sympatric species, was also discussed.

Genetic diversity and morphological stasis in the Ceylon Snakehead, Channa orientalis (Teleostei: Channidae)

As the type species of the genus Channa, the identity of the pelvic-finless snakehead Channa orientalis Bloch is important to channid systematics. Although this name has been attached to a Sri Lankan species for the past 160 years, its vaguely specified type locality, ‘India Orientali’, has long cast doubt as to its origin. Here, based on a collection across its range in the island and analysis of the cytochrome c oxidase subunit 1 (cox1) barcoding gene, we show that the Sri Lankan pelvic-finless Channa is composed of two geographically discrete lineages separated by an uncorrected pairwise cox1 genetic distance of 6.9–8.1%. The minimum genetic distance between these two lineages and other species of the Gachua group of Channa is 5.1%. Despite their genetic divergence, the two lineages exhibit remarkable morphological stasis: they are indistinguishable from each other in external morphology. We argue that the type locality of C. orientalis is south-western Sri Lanka, to which the species is endemic. Channa orientalis is distinguished from other species of Channa by the absence of pelvic fins, adult coloration in life, dorsal- and anal-fin ray counts, number of vertebrae, and scale counts.

Identification of Black Bullhead (Ameiurus melas) and Brown Bullhead (A. nebulosus) from the Western Great Lakes: Recommendations for Small Individuals

Distinguishing Black Bullhead (Ameiurus melas) from Brown Bullhead (A. nebulosus) can be difficult, in part, due to conflicting evidence regarding reliable meristic and morphological characters with which to base identifications. The possibility of hybrids with intermediate traits further complicates diagnosis. Identification guides have typically focused on adults, leaving guidance for juveniles largely undescribed. We compared morphological identifications of Black Bullhead and Brown Bullhead with a cytochrome c oxidase I (COI) barcode and microsatellite assignments. Specifically, we examined: (1) gill-raker count, (2) anal-fin ray count, (3) prominence of pectoral-spine serrae, (4) DNA barcoding using the COI gene, and (5) cluster analysis of nine microsatellite loci. With the exception of anal-fin ray counts, we found a high degree of agreement among all methods. Microsatellite analysis identified two clearly distinct genetic groups, and these groups corresponded to individuals identified as Black Bullhead and Brown Bullhead based on morphology. Although Black Bullhead and Brown Bullhead did not share COI haplotypes (except for one individual), we found greater intraspecific genetic distances among individuals identified as Brown Bullhead than between Brown Bullhead and Black Bullhead, demonstrating that caution is warranted against using COI haplotypes as a barcode to solely distinguish the two species. Pectoral-spine serrae prominence was a useful character to distinguish the two species and worked especially well on individuals <125 mm total length. Gill-raker counts of euthanized fish in the laboratory were appropriate for the identification of all sizes of Black Bullhead and Brown Bullhead (using the lowest number of gill rakers on the first gill arch if asymmetry was observed). Finally, microsatellites did not show evidence of recent hybridization at our sampling sites. We recommend using pectoral-spine serrae prominence to distinguish between Black Bullhead and Brown Bullhead in the field and using gill-raker counts for laboratory based identification.

A new sea catfish, Netuma patriciae (Siluriformes: Ariidae), from the Philippines

A new sea catfish (Ariidae), Netuma patriciae, is described based on the holotype and nine paratypes, 127.3–303.4 mm in standard length, collected from Panay and Luzon islands, Philippines. The new species most resembles N. thalassina (Ruppell 1837), in sharing counts of anal-fin rays (17–19 in N. patriciae, 15–17 in N. thalassina) and a distinct dorsomedian head groove (longitudinal length of the groove, 33.7–40.1% of head length, 22.3–31.0%). However, the new species can be easily distinguished from the latter in having fused vomerine tooth patches, and more numerous free vertebrae (43–44 vs. 41–42 in N. thalassina). Although N. bilineata (Valenciennes in Cuvier and Valenciennes 1840a) has also fused vomerine tooth patches, the new species is distinguished by having fewer free vertebrae (43–44 vs. 47–51 in N. bilineata) and longer dorsomedian head groove (33.7–40.1% of head length vs. 0–9.7%). The new species can also be easily distinguished from both N. thalassina and N. bilineata by having a filamentous dorsal-fin ray (longest dorsal-fin ray 26.9–35.9% of standard length vs 20.3–23.3% in N. thalassina, 20.9–25.3% in N. bilineata, standard length > 127 mm) and a U-shaped junction of dorsomedian head ridge (vs. V-shaped in both species).

Morphological Differences and Trophic Niche Breadth of Sarotherodon galilaeus and Oreochromis niloticus from the Freshwater Lake Geriyo, North-Eastern Nigeria

Abstract The relationship between morphological traits and feeding ecology of the only two tilapiine cichlids (Sarotherodon galilaeus and Oreochromis niloticus) in Lake Geriyo, northeastern Nigeria, was examined. Stomach contents of 504 individuals were examined and analyzed to relate morphological differences of each species to its dietary preferences. Eleven ecological relevant morphological variables, including total length, standard length, head length, body depth, eye diameter, pectoral spine length, pelvic spine length, dorsal fin ray count, dorsal spine count and anal fin ray count, were also measured and subjected to Principal coordinate analysis (PCoA) to relate morphological differences of each species to its dietary preferences. The PCoA (using Euclidean distance) revealed a large morphological distance between species indicating adaptation for different spatial and vertical distributions within the lake. Furthermore, the correlation of these morphological differences with particular diet categories suggests a potential for specialized trophic tendencies, however, the high occurrence of two major food types (macrophytes and plankton) in stomach contents of both species indicate generalist trophic tendencies. While a high trophic overlap index (0.98) was recorded for both species, the trophic niche breadth was higher for S. galilaeus (4.18±0.32), compared to O. niloticus (3.33±0.24). Despite the large morphological differences of both tilapias, the high trophic overlaps indicate limited food options within Lake Geriyo. In addition, the successful coexistence of the tilapias in the face of limited food resources indicates suitable partitioning of food resources in the lake.

A new species of Hypopygus Hoedeman (Gymnotiformes: Rhamphichthyidae) from the rio Trombetas system, Amazon basin, Brazil.

A new Hypopygus species is described from the igarapé Saracá, a stream in the lower rio Trombetas system, Pará State, Brazil. It differs from congeners by a unique combination of characters (either primitive or of uncertain polarity) which includes mouth position, interocular width, snout length, postorbital length, pectoral-fin length, snout-to-occiput length, caudal-filament length, counts of pectoral-fin rays and anal-fin rays, distribution of anal-fin chomatophores, as well as a set of osteological features. A phylogenetic analysis indicates that the new species, belongs to a monophyletic subgroup in Hypopygus that includes all congeners, except H. neblinae; its relationships within that clade, however, are currently uncertain, and a brief discussion is provided. Corrections are made concerning some morphometric and meristic information furnished in recent contributions regarding Hypopygus species.

Phylogeography of Lionfishes (Pterois) Indicate Taxonomic Over Splitting and Hybrid Origin of the Invasive Pterois volitans.

The lionfish is an iconic marine fish, and recently renowned for a disastrous introduction into the West Atlantic. Genetic surveys of the putative invaders (Pterois volitans and Pterois miles) in their natural Indo-Pacific range can illuminate both topics. Previous research indicated that P. volitans and P. miles are sister species that hybridize in the invasive range, but hybridization in the native range is unknown. Here, we apply mtDNA COI and 2 nuclear introns (S7 RP1 and Gpd2) from 229 lionfish including the 2 invaders and 2 closely-related taxa (44 P. miles, 91 P. volitans, 31 Pterois lunulata, and 63 Pterois russelii) from 10 locations in their native ranges. Genetic data are supplemented with key morphological characters: dorsal, anal, and pectoral fin ray counts. We observed 2 lineages (d = 4.07%, 0.89%, and 2.75% at COI, S7 RP1, and Gpd2, respectively) among the 4 putative species: an Indian Ocean lineage represented by P. miles, and a Pacific Ocean lineage represented by P. lunulata and P. russelii. All specimens of the invasive P. volitans appear to be hybrids between the Indian Ocean P. miles and a Pacific lineage encompassing P. lunulata/russelii, a conclusion supported by both genetics and morphology. The divergences between Indian and Pacific forms are within the range of species-level partitions in fishes, and we recommend retention of the names P. miles and P. russelii for Indian and Pacific forms. The hybrid origin of the Atlantic invasion invokes the possibility of heterosis as a contributing factor to invasion success.

A new species of the blind and miniature genusMicromyzonFriel and Lundberg, 1996 (Silurifomes: Aspredinidae) from the Orinoco River: describing catfish diversity using high-resolution computed tomography

A new species of the aspredinid catfish tribe Hoplomyzontini Micromyzon is described from two specimens collected with trawl nets in two localities, at 10 and 18 m depth, in the main channel of the lower Orinoco River in Venezuela almost 40 years ago. The new species is distinguished from its only congener, Micromyzon akamai, by the: straight anterior margin of the mesethmoid; open posterior cranial fontanel; ossified first pectoral-fin radial; single tubular infraorbital bone; infraorbital sensory canal entering neurocranium via the frontal; enclosed foramen for the abductor superficialis muscle in the coracoid; higher vertebral count (33 vs. 28–32); higher anal-fin ray count (10 or 11 vs. 7–9); and some morphometric features. The holotype of the new species was scanned using High-Resolution X-ray Computed Tomography to illustrate, describe, and compare its bony skeleton to other hoplomyzontins.

Phenotypic plasticity during early ontogeny in cultured turbot (Scophthalmus maximus): changes in dorsal and anal fin ray counts by water temperature

Summary Plastic responses to environmental conditions are crucial among ectothermic organisms, and any traits induced early in ontogeny may have long-term effects. Here, we studied how turbot larvae altered their morphology in three different thermal environments and assessed whether different thermal regimes affected the survival, growth, development and morphology of juvenile turbot at the end of metamorphosis. Therefore, newly hatched Turbot (Scopthalmus maximux L.) larvae were divided into three groups and reared at 14, 18 and 22°C until 80 days after hatching. Environmental temperature was seen to affect several turbot traits. Low temperature induced low dorsal and anal fin ray counts, but had no effect on gross body morphology. There were differences in growth and skeletal development rates, but no differences in survival. There were also no differences in the skeletal malformations occurring in response to environmental temperature treatment. Collectively, these results supported the idea of the existence of a thermal plastic response, as found, in other fish species.

The Marked Goby (Ctenobgobius stigmaticus): A Rare North Carolina Fish Enigma

Abstract The marked goby (Ctenogobius stigmaticus Poey, 1860) is a diminutive, uncommon, tropical-subtropical Atlantic fish. It is considered rare in North Carolina. It has been confused in the past with the similar darter goby (Ctenogobius boleosoma Jordan and Gilbert, 1882) and considered common in North Carolina. Recently, some of the confusion has been eliminated and characters to separate these two similar gobies identified. These characters were used to determine that six specimens were collected and cataloged from the state (one is missing, but a photograph has the marked goby coloration). Examining the remaining five, it became obvious that only one is C. stigmaticus. The four others are presumably the darter goby, as anal fin ray counts (which presumably was used to separate them) may overlap. Differences in head shape, maxillary length relative to eye, and the presence of tusks in C. stigmaticus compared to the darter goby could be considered in future keys. Color patterns are also strikingly different in specimens where color still exists. Unfortunately, the four specimens in question lack clear color patterns after preservation. Thus, only two specimens of the marked goby from North Carolina are known. Fortunately, these specimens were captured with substantial environmental data during the most intensive inshore aquatic survey of fishes and macroinvertebrates in the state: daily sampling from March to November 1968–1977 with varied gear in the lower Cape Fear River and adjacent ocean. The range of the marked goby thus extends from SE North Carolina to the border of Brazil and Uruguay, roughly 34 N to 34 S. All specimens have been taken in large lagoons or estuarine bays, in shallow to intertidal waters, on muddy-sand bottoms, and in moderate salinities. The difficulty in sampling these small (≤80 mm TL), slender fishes may also contribute to their scarcity and lack of knowledge.

Growth-related morphology of “Kunimasu” (Oncorhynchus kawamurae: family Salmonidae) from Lake Saiko, Yamanashi Prefecture, Japan

Biological characteristics of “Kunimasu” (Oncorhynchus kawamurae), poorly known even before the species was prematurely believed extinct, have now become apparent following the examination of 59 specimens from Lake Saiko, Yamanashi Prefecture, Japan and comparison with 58 examples of “Himemasu” (kokanee of Oncorhynchus nerka in Japan), also from Lake Saiko. Significant (p < 0.01) differences between Kunimasu and Himemasu from Lake Saiko occurred in counts of anal-fin rays, pectoral-fin rays, gill rakers (no overlap found) and pyloric caeca. Secondary sexual characters related to maturity level were also found in Kunimasu, the body being more compressed in pre-spawning and spawning males and females than in immature and maturing individuals. Furthermore, maturing male Kunimasu and Himemasu also differed in body shape. Body coloration of Kunimasu also differed according to level of maturity, the nuptial coloration in both sexes being olive-green when alive and black when fresh. Dark dots, found in ca. 40 % of Kunimasu individuals examined, were less distinct than in Himemasu. The spawning season of Kunimasu extended through winter and early spring in Lake Saiko, with spawning males and females remaining near the bottom, compared with non-spawning individuals which occupied the upper and middle profundal zones in the daytime.

Callogobius liolepis Bleeker, a senior synonym of Gobiopsis aporia Lachner and McKinney (Teleostei: Gobiidae: Gobiopsis).

Callogobius liolepis Bleeker in Koumans was briefly described from two specimens from Ambon. A later, more detailed description by Koumans was apparently based on Bleeker's unpublished description and specimens of C. okinawae (Snyder), considerably complicating the taxonomy of several species. Re-examination of the syntypes identifies C. liolepis as a species of the genus Gobiopsis Steindachner due to the absence of raised vertical ridges of papillae that characterise Callogobius and the presence of barbels in a pattern unique among gobiids to a subset of Gobiopsis. Gobiopsis liolepis (Bleeker) is determined as the senior synonym of G. aporia Lachner and McKinney based on the absence of head pores combined with the presence of a series of tightly spaced papillae over the eye, lateral scale counts of 36-42, pectoral-fin ray counts of 20-21, dorsal-fin ray counts VI+I,10 and anal-fin ray counts of I,9. The larger syntype is designated the lectotype and the smaller the paralectotype. Specimens identified as C. liolepis in museums or the literature are likely referable to C. okinawae (Snyder) or C. bifasciatus (Smith).

Kanekonia leichhardti, a new species of velvetfish (Actinopterygii: Scorpaeniformes: Aploactinidae) from the Gulf of Carpentaria, Queensland, Australia)

Kanekonia leichhardti, new species, is described from three specimens dredged on soft bottom in the eastern Gulf of Carpentaria, Queensland, Australia. It is distinguished from its three congeners by a combination of mostly smooth skin with minute, sparsely distributed velvety scales, long snout, narrow head and body, slightly notched predorsal profile, low anal-fin ray and lateral-line tube count, and distinctive configuration of the interorbital ridges (interorbital ridges not prominently sculptured, converging anteriorly to form an inverted Y shape, the symphysis above a vertical from the middle of the eye, and continuing as a single ridge to the base of the first dorsal-fin spine). The species appears to be rare and possibly endemic to the waters of the Gulf of Carpentaria. Wide-ranging surveys conducted with similar gear on the north-west shelf of Western Australia and coastal and inter-reef soft bottom habitats from Torres Strait south throughout the entire length of the Great Barrier Reef have failed to collect any further specimens.

A new species of the Genus Microbrotula (Teleostei: Bythitidae) from Cenderawasih Bay, New Guinea, Indonesia

Following the recent revision of Microbrotula (Schwarzhans &amp; Nielsen, 2011), an additional nine specimens of the vivi-parous genus Microbrotula (Teleostei: Bythitidae), all caught in the Cenderawasih Bay, Irian Jaya, New Guinea, Indone-sia, were made available to us. These specimens represent a new species described here as M. geraldalleni. It belongs tothe group of species with 6 caudal and 14 pectoral fin rays and is closest to M. greenfieldi, differing in the higher dorsaland anal fin ray counts (68–73 and 61–65 vs. 62–70 and 58–61, respectively), the presence of 3 posterior mandibular pores(vs. none), 2–3 preopercular pores (vs. none), a connected squamation over the head including cheek, opercle and occiput(vs. 3 separated scale patches) and with a unique scale-less triangular window just above the opercle. Microbrotula geraldalleni may be endemic to the Cenderawasih Bay.

Microgobius urraca (Teleostei: Gobiidae), a new species of goby from the tropical eastern Pacific

A new species of goby in the genus Microgobius (Teleostei: Gobiidae: Gobiosomatini) is described from the Pacific coastof Panama. It is morphologically similar to M. erectus, but differs from that species in possessing fewer lateral scale rows,lacking a patch of ctenoid scales under the pectoral fin, having unpigmented epaxial myosepta, having a distinct oval-shaped dark blotch on the first dorsal fin, and possessing three blue-white stripes on a dark caudal fin. Differences in boththe number and type of scales, dorsal and anal fin ray counts, the poor development of a fleshy dorsal crest, and overallcolor patterns further distinguish this species from the remaining eastern Pacific congeners. Photographs of all Pacific species of Microgobius and a dichotomous key to the Pacific members of the genus are provided.

Revision of the genus Parequula (Pisces: Gerreidae) with a new species from southwestern Australia

The genus Parequula, which has long been considered monotypic, is reviewed with a new species described fromsouthwestern Australia on the basis of 21 types and 17 non-type specimens (42–81 mm in standard length); its onlycongener, P. melbournensis (Castelnau), is also redescribed. Parequula elongata n. sp. differs from P. melbournensis inhaving a more slender body, a lower soft anal-fin ray count (14–15, mode 15 vs. 16–18, mode 17), a lower pored lateral-line scale count (34–35, mode 34 vs. 37–40, mode 38), and the dorsal fin with a reddish upper margin when fresh (vs.semi-translucent to bluish with a narrow, parallel, yellowish vertical line on each fin membrane and a yellowish fin marginin P. melbournensis). Furthermore, the head profile of P. elongata n. sp. is nearly straight to slightly convex, whereas P.melbournensis is distinctly concave in outline above the eyes. Nominal species (junior synonyms) of P. melbournensis are discussed and a key to the two species is also provided.

A new species of the deepwater clingfish genus Kopua (Gobiesociformes: Gobiesocidae) from the East China Sea—an example of antitropicality?

A new species of deepwater clingfish, Kopua japonica sp. nov., is described from the East China Sea. It is distinguished fromthe other members of the genus by anal and dorsal fin ray counts and a unique arrangement of sensory pores on the head. It isalso the first record of the genus from the Northern Hemisphere and this record may be an important deepwater addition to antitropicality in marine fishes.

Systematic revision of the formerly monotypic genus Tanganikallabes (Siluriformes: Clariidae)

The monotypic genus Tanganikallabes, endemic to Lake Tanganyika, is a poorly known member of the family Clariidae. Examination of 142 specimens housed in museum collections has revealed the presence of at least two additional species in this genus. Tanganikallabes alboperca sp. nov. is distinguished from all congeners by the length of its pelvic fins, the presence of a depigmented vertical bar on the opercular margin, and a combination of additional morphometric (pectoral spine length, preanal length, body depth at anus) and meristic (dorsal and anal fin ray counts) characters. Tanganikallabes stewarti sp. nov. is distinguished from other Tanganikallabes species by having a relatively shorter, incomplete lateral line, and shallow body depth at the anus, as well as shorter prepelvic and preanal lengths, and a longer anal fin with a higher number of fin rays. Several morphological characters, as well as genetic data from cytochrome b (mitochondrial DNA) and 18S–ITS1–5.8S–ITS2–28S (ribosomal DNA), indicate that Tanganikallabes constitutes a monophyletic group within the Clariidae and support the recognition of additional species diversity. The monophyly of Tanganikallabes, coupled with the geographical isolation of this group to a single lake satisfy the requirements for its classification as a true species flock, the latest to be described from Lake Tanganyika. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 121–142.

Discovery of fossil Ayu (Plecoglossus altivelis) from the Upper Miocene of Shimane Prefecture, Japan

The Ayu, Plecoglossus altivelis, comprising three subspecies, is the only species in the genus Plecoglossus in the family Osmeridae. Here, we describe for the first time the discovery of fossil specimens of P. altivelis from the Upper Miocene sediment of Matsue, Shimane Prefecture, Japan. The fossil individuals are subadult and have comb teeth in the second and third generations. These fossil specimens are clearly similar to the recent P. altivelis, the former’s meristic characters being included in the three recent subspecies. In terms of numbers of pectoral fin rays and vertebrae, the fossil specimens are more similar to the subspecies Plecoglossus altivelis ryukyuensis than the other subspecies, but they also show different dorsal fin shapes and anal fin ray counts. This discovery of fossil P. altivelis indicates the persistence of the species for at least 10 million years, from the Late Miocene to the present.

Variation in fin ray counts of 0-group turbot ( Psetta maxima) and brill ( Scophthalmus rhombus) on the west coast of Ireland: 2006–2009

Recently settled turbot Psetta maxima and brill Scophthalmus rhombus are difficult to distinguish, as they are almost identical in appearance and lack the diagnostic adult characteristics. Fin ray counts, which can be used as an aid in the identification of flatfish juveniles, are reported to show some overlap between turbot and brill. 0-group flatfish were collected from sandy beaches along the west coast of Ireland by beach seining in 2009. When counted and plotted, the dorsal and anal fin ray counts clearly separated the specimens into two groups. The two groups were assumed to be brill and turbot on the basis of literature data, suggesting higher dorsal and anal fin ray counts occur in brill. This confirmed that fin ray counts can probably be used as a diagnostic tool in these 0-group flatfish from west of Ireland waters. Additionally, temporal and spatial variability in fin ray counts was also revealed in the present study, emphasizing that regional difference need to be taken into account when using this diagnostic method.