Pectoral-fin Rays Research Articles

Two new species of eelpout genus Lycenchelys (Perciformes: Zoarcidae) from the Kuril-Kamchatka Trench, based on morphological and molecular evidence

Two new species of eelpout genus Lycenchelys Gill, 1884 are described based on eight specimens caught at a depth between 3517 and 3580 m at the western slope of the upper margin of the Kuril-Kamchatka Trench, relatively close to the Bussol Strait and Simushir Island in the center of the Kuril Islands chain. Lycenchelys delanglei sp. nov. differs from its congeners by the following combination of characters: vertebrae 28–29 + 91–93 = 120–121; interorbital and occipital pores absent; postorbital pores 4; suborbital pores 10–12; preoperculomandibular pores 4 + 5; gill rakers 11–16; dorsal-fin rays 114–117, 2–3 free pterygiophores at the beginning of dorsal fin; anal-fin rays 96–98; pelvic-fin rays 2; pectoral-fin rays 16–17, ray tips of the pectoral fin exserted, especially the middle and lower ones; lateral line absent; pyloric caeca not developed. Lycenchelys renatae sp. nov. differs from its congeners by the following combination of characters: vertebrae 26–27 + 99–103 = 125–130; interorbital pores 0–1; occipital pores absent; postorbital pores 1–4; suborbital pores 6–9; preoperculomandibular pores 3–4 + 5; gill rakers 13–15; dorsal-fin rays 115–122, 1–3 free pterygiophores at the beginning of dorsal fin; anal-fin rays 102–106; pelvic-fin rays two; pectoral-fin rays 16–17, ray tips of the pectoral fin exserted, the middle and lower ones more so than the upper ones; lateral line mediolateral, poorly developed; pyloric caeca not developed. For each of the two described new species four mitochondrial COI sequences were analysed and share the same haplotype within species. The obtained DNA barcodes allowed discrimination of L. delanglei sp. nov. and L. renatae sp. nov. from each other and exhibit a genetic distance of 2,61%. The closest match of L. delanglei sp. nov. with already published sequences was Lycenchelys lenzeni with a sequence similarity of 98.47%, whereas the closest match of L. renatae sp. nov. with already published sequences was Lycenchelys jordani with a similarity of 98.62%. A new analysis of radiographs of the type specimens confirmed that L. birsteini should be considered as synonym of L. plicifera, especially due to similar numbers of free pterygiophores at the beginning of dorsal fin.

Validation of Icelus crassus Andriashev (Cottiformes: Cottidae), described from the Sea of Okhotsk

The validity of the Stocky Sculpin Icelus crassus Andriashev, described from the Sea of Okhotsk, was confirmed following examination of the type series; the species having been previously considered a synonym of I. ochotensis Schmidt. Although both species belong to the “I. bicornis” (sensu Nelson 1984) species group, having suborbital spines and additional rows of scales on the body absent (excluding dorsal-row and lateral-line scales), and fine marginal serrations on the dorsal-row scales rather than sharp single spines, I. crassus differs from the type series of I. ochotensis in the absence of parietal spines (vs. present), supraorbital cirri present as expanding, distally branched laminae (vs. simple barbels), dorsal scale row incomplete anteriorly (vs. complete, reaching head); and lateral-line scales serrated below each sensory canal pore (vs. embedded in skin below each pore, usually with no more than 1–2 spinules). Meristic characters of I. crassus, similar to other species of the “I. bicornis” group, include 38–41 vertebrae, IX 18–20 dorsal-fin rays, 15 or 16 anal-fin rays, 17–19 pectoral-fin rays, 41–43 lateral-line scales, 25–31 dorsal-line scales, and 10–17 axillary scales. The urogenital papilla is cylindrical (not spatulate), with a short, claw-like terminal appendage. The holotype is found in ZIN collection, No. 21900, adult male TL 106 mm. Icelus crassus has been recorded in the Sea of Okhotsk and Sea of Japan (Strait of Tartary) 97–327 m depth; near bottom, water temperatures range from -0.7°C to 2.15°C.

A new species of Phenacorhamdia (Siluriformes: Heptapteridae) from the Juruena River basin, with insights into its phylogenetic position

Heptapteridae is a group of small to medium-sized neotropical catfish composed of 23 genera and 238 valid species, classified into two subfamilies: Rhamdiinae and Heptapterinae. Phenacorhamdia represents small heptapterids and is composed of 14 valid species distributed across all major river basins in South America. In this paper, we add another species to the genus, described from the Juruena River basin, Mato Grosso state, Central Brazil. This species is distinguished from its congeners by having multicuspid teeth, 47–52 vertebrae, maxillary barbel not reaching to pectoral-fin origin, and absence of a short extension of the first pectoral-fin ray. Additionally, a brief discussion on its putative phylogenetic position, based on UCEs dataset, is provided.

A new freshwater goby of Rhinogobius Gill, 1859 (Teleostei, Gobiidae) from South Central Vietnam

A new species of freshwater gobiid fish of genus Rhinogobius Gill, 1859, was collected from the Cai Phan Rang River basin, South Central Vietnam. Rhinogobius phuocbinhensis n. sp. can be well distinguished from other congeners by its specific patterns of coloration and meristic features: (1) fins rays: second dorsal fin rays I/8; anal fin rays I/8; pectoral fin rays modally 19; (2) squamation: longitudinal scale series 26–27 (modally 27); perdorsal scales 9–11 (modally 9); vertebral count 26; and (3) specific colouration pattern: densely-set of small blackish brown spots on cheek and interorbital region to snout in male and many small blackish brown dots in first dorsal fin of both sexes. A brief morphological comparison of this new species with related species would be also addressed.

Two new species of Paratanakia (Teleostei: Cyprinidae) from Taiwan and mainland China

Two new species of bitterling of Paratanakia were found and collected from Taiwan island and Fujian Province, mainland China recently. Paratanakia fuvlidorsalis n. sp. which is endemic in Taiwan island can be well distinguished from other congeners by the following unique combination of features: (1) fin ray counts: dorsal fin rays 3, 8; anal fin rays 3, 10; pectoral fin rays modally 1, 12; (2) squamtion: lateral-line scales modally 34; and (3) its own specific dorsal fin color pattern in male. Paratanakia julongjiangensis n. sp. which is endemic in Fujian Province, mainland China can be well distinguished from other congeners by the following unique combination of features: (1) fin ray counts: dorsal fin rays 3, 9; anal fin rays 3, 11; pectoral fin rays modally 1, 12; (2) lateral-line scales modally 34; and (3) its own specific dorsal fin color pattern in male. The brief morphological comparison with close related species would be also addressed.

Two new species of Luciogobius Gill (Teleostei: Gobiidae) from the Matsu Islands in Taiwan

Two new gobiid fishes of Luciogobius Gill, 1859 have recently been collected from the intertidal waters of the Matsu Islands in Taiwan. The first new species, Luciogobius matsuensis sp. nov., is characterized by the following unique combination of features: (1) second dorsal fin rays: I/12 and anal fin rays I/12; (2) pectoral fin rays modally 16 and with one upper, short free soft ray; (3) vertebral count modally 17+20–21=37–38; and (4) specific coloration: second dorsal fin translucent with tiny brown spots; caudal fin with many tiny brown spots; anal fins pale yellow and translucent, spotless, and darker in its rays; and pectoral fin creamy yellow with anterior 2/3 region with tiny brownish to black spots. The second new species, Luciogobius dongyinensis sp. nov., is characterized by the following unique combination of features: (1) second dorsal fin rays: I/16 and anal fin rays I/16; (2) pectoral fin rays modally 14 and with 2 upper, short free soft rays; (3) vertebral count modally 18+23=41; and (4) specific coloration: a long infraorbital deep brown stripe below eye; a long deep brown stripe above and along upper jaw; pectoral fin with many small patches of melanophores except posterior, distal 1/5 region; and caudal fin brown with many light rounded spots. A brief discussion of their own related species will also be addressed.

A new freshwater gobiid species of Rhinogobius Gill, 1859 (Teleostei: Gobiidae) from Minjiang river basin, Fujian Province, southeastern China

A new freshwater gobies of Rhinogobius Gill, 1859 were discovered from the Minjiang Basin, Fujian Province, southeastern China. It belongs to fluvial species. The new species, Rhinogobius dongfongensis n. sp. which collected from Fujian Province of China can be well distinguished from all other congeners by the unique combination of the following features: (1) fins: second dorsal fin rays modally I/8–9; anal fin rays I/7; pectoral fin rays modally 15; (2) squamation: longitudinal scale series 32–33 (modally 33); perdorsal scales usually 5–6; (3) normal vertebral count 26; (4) rear edge of mouth merely extending beyond vertical of anterior margin of pupil in male and (5) its own specific colouration. The brief comparison and discussion of morphological differentiation from congeners of mainland China would be addressed.

Two new freshwater gobiid species of Rhinogobius Gill, 1859 (Teleostei: Gobiidae) from Taiwan

Two new freshwater gobies of Rhinogobius were discovered from Taiwan. They are fluvial species belonging to R. rubromaculatus complex. The new species, Rhinogobius baborinisanensis n. sp. which is collected from northern Taiwan can be well distinguished from all other congeners by the unique combination of the following features: (1) fins: second dorsal fin rays modally I/8; anal fin rays I/7; pectoral fin rays modally 17; (2) squamation: longitudinal scale series 32–34 (modally 33); perdorsal scales usually 13–14; scale series from origin of first dorsal fin to upper pectoral fin origin modally 10; (3) vertebral count 27; (4) rear edge of mouth merely extending to or slightly beyond vertical of anterior margin of pupil in male and (5) its own specific colouration. Another new species, Rhinogobius macromaculatus n. sp. which is collected from southern Taiwan can be well distinguished from all other congeners by the unique combination of the following features: (1) fins: second dorsal fin rays modally I/8; anal fin rays I/7; pectoral fin rays modally 15; (2) squamation: longitudinal scale series 27–28 (modally 28); perdorsal scales usually 14–15; scale series from origin of first dorsal fin to upper pectoral fin origin modally 8; (3) vertebral count 27; (4) rear edge of mouth extending slightly beyond vertical of anterior margin of pupil in male and (5) its own specific colouration. The brief comparison and discussion of morphological differentiation from congeners would be also addressed.

Redescription of Parascorpaenamoultoni (Whitley, 1961) (Actinopterygii, Scorpaenidae), with new distribution records for the species.

Although the status of Parascorpaenamoultoni (Whitley, 1961) is now well established, the morphology of the species has been re-examined, with new diagnostic features identified. Typically 15 or 16 pectoral-fin rays are present, together with two suborbital ridges, each with a single spine and the origin of the first ridge posterior to the second, well-developed interorbital ridges forming a loop, an undeveloped occipital pit, no scales on the dorsal- and anal-fin soft ray bases. The known range of the species includes Taiwan, the Philippines, Micronesia, Indonesia, Timor-Leste, Papua New Guinea, Solomon Islands, Vanuatu, and Fiji in addition to previously reported Australia, New Caledonia, and Japan.

Oreichthys warjaintia, a new species of cyprinid fish from Meghalaya, India (Cypriniformes: Cyprinidae).

Oreichthys warjaintia, new species, is described from the Pyrngang stream (Surma-Meghna basin), Meghalaya, northeast India. It can be distinguished from all known species within the genus Oreichthys in having the following combination of characters: complete lateral line with 25-27 pored scales, 13 branched pectoral-fin rays, 5-5½ branched anal-fin rays, 14 rows of papillae on suborbital, ½3/1/2½ scale rows in transverse line on body, presence of a black blotch on caudal-fin base, and in the coloration of dorsal, caudal, and anal fins. Oreichthys warjaintia is distinct from all known Oreichthys species for which mitochondrial cox1 sequence data are available by a raw genetic distance ranging from 8.3% to 11.1%.

A new species of Hoplostethus from Sumatra, eastern Indian Ocean, with comments on its most similar congeners (Trachichthyiformes: Trachichthyidae).

A new species of the roughy fish genus Hoplostethus, subgenus Leiogaster, is described based on three specimens collected from Sumatra, Indonesia. This species can be distinguished from its congeners by the following characteristics: gular region covered with ctenoid scales; pelvic-fin spine smooth on its anterior edge; head depth subequal or smaller than its length (37.2%-38.6% standard length [SL], or 94.7%-99.2% head length [HL]); pectoral-fin length 35.6%-37.8% SL, reaching beyond a vertical through anal-fin origin; abdominal scutes well developed, 12-16; pectoral-fin rays uniformly black, 17-19; gill rakers on the first arch 6-7 + 1 + 13-14 = 21; pre-dorsal scales 24-27; and pyloric caeca 32. A detailed description is provided along with comparisons with its congeners. Additionally, diagnostic characters of the congeners and literature records of Hoplostethus rubellopterus and Hoplostethus melanopus are discussed.

Diving deeper into the taxonomy of the Neoscopelus species complex (Myctophiformes: Neoscopelidae) with the description of Neoscopelus serranoi sp. nov.

Previous studies have highlighted possible cryptic biodiversity in the genus Neoscopelus. This hypothesis was tested using new morphological, molecular and biogeographical data on species of this genus caught in the north Atlantic between 2010 and 2022. The information obtained has been combined with available data in an integrative approach, including a review of morphological characters reported in the ichthyological literature and DNA-based species delimitation analyses. The main outcome of the present study is the description of Neoscopelus serranoi sp. nov. from the Atlantic and southwestern Indian Oceans. The new species is morphologically very similar to Neoscopelus microchir from which differs in having a shorter anal-fin base, a shorter pelvic fin, more dorsal and pectoral-fin rays, less anal-fin rays, fewer gillrakers and fewer isthmus and lateral photophores. They also differ in geographic distribution, with the new species occurring in the Atlantic Ocean and the near southwestern Indian Ocean, whereas N. microchir was originally described from Japanese waters of the Pacific Ocean. A literature review of available morphological data between geographic areas for Neoscopelus macrolepidotus and Neoscopelus microchir showed a large intraspecific overlap and no boundaries. However, molecular species delimitation based on the mitochondrial COI gene revealed the existence of cryptic diversity in both species, with eight to ten molecular operational taxonomic units (MOTU), compared to three valid species. Neoscopelus serranoi sp. nov. was considered an independent MOTU in all analyses performed, supporting the morphological identification as a new species. These results highlight that the taxonomy of Neoscopelus is far from settled and show that a greater sampling effort is needed to resolve the uncertainties and to describe unknown putative species. This also exemplifies the virtues of integrative taxonomy in delving into the systematics of deep-sea fishes.

Description of two new species of the genus Paranemachilus (Cypriniformes, Nemacheilidae) from Guangxi, China

This study describes two new species within the genus Paranemachilus. Paranemachilus luegvetensissp. nov. and Paranemachilus liuisp. nov. can be distinguished from all recognized congeners by a combination of morphological characteristics and substantial genetic divergences. Paranemachilus luegvetensissp. nov. is characterized by scaled cheeks; the whole body covered in scales, except for the head; 11–12 branched pectoral fin rays; 4–5 preoperculomandibular canal pores; body depth 13.5%–16.8% of standard length; and preanus length 68.3%–73.9% of standard length. Paranemachilus liuisp. nov. is characterized by scaled cheeks; the whole body covered in scales except for the head; 11–13 branched pectoral fin rays; 11–15 supraorbital canal pores at the base of the anterior nostrils; 7–9 preoperculomandibular canal pores; preanus length 67.4%–74.3% of standard length; snout length 21.4%–28.7% of lateral head length.

Primary and Secondary Sexual Characteristics of Kuhli Loach (Pangio kuhlii)

Kuhli loach (Pangio kuhlii) a popular ornamental freshwater fish species with economic potential, originating from Sumatra, Kalimantan, Java, and Malaysia. The kuhli loach's appeal lies in its vibrant colors and distinctive eel-like body. This study aims to explores the sexual primary and secondary characteristics of the kuhli loach. Conducted at Universitas Airlangga in Banyuwangi, Indonesia, the study involved a thorough analysis of 50 kuhli loaches, evenly split between males and females. Morphological observations revealed significant differences (p < 0.05), such as the elongated body and expanded abdominal region in females, suggesting adaptations for reproduction. Internal examinations, including peritoneal dissections and histological analysis, unveiled distinct stages of spermatogenesis in males and ovarian development in females, providing insights into the reproductive cycle. Meristic and morphometric analyses identified noteworthy differences in pectoral fin rays, suggesting potential roles in reproductive behavior, while other traits exhibited similarity between genders. This study contributes to the understanding of kuhli loach ecology and reproductive biology, highlighting the importance of addressing sustainability concerns arising from the continuous exploitation of wild populations. This study serves as a foundational step towards advancing reproductive improvement in fish and supports the conservation of this unique ornamental fish species, with implications for aquaculture practices and economic considerations.

Garra dohjei, a new species of labeonine fish (Teleostei: Cyprinidae) from Meghalaya, India.

Garra dohjei, a new labeonine fish with transverse lobe and incipient proboscis is described from the Ñiangdai, a tributary of the Brahmaputra River, Meghalaya, India. The new species is distinguished from its congeners with transverse lobe and incipient proboscis, in having a well-developed transverse lobe with around 9-12 minute tubercles, deep transverse groove between transverse lobe and incipient proboscis, black spot immediately anterior to upper angle of gill opening, 5-6 dark black stripes on caudal peduncle, 33-35 lateral line scales, 9-10 predorsal scales, 16-circumpeduncular scales, 15 branched pectoral-fin rays, and total vertebrae 33.

Processing time and precision of aging structures for Bighead Carp and Silver Carp in the lower Red River catchment in the southern Great Plains

AbstractObjectivePopulation demographics of invasive species are commonly evaluated to better develop management actions that are useful for reducing their abundance or controlling the population. Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix are emblematic invaders in the United States, where they continue to expand their range. There is currently no consensus about which hard structure from these species is best for age estimation. Our study objective was to compare the processing time and precision of five hard structures used for age estimation of both species.MethodsWe sampled fish in the lower Red River catchment of Oklahoma, Arkansas, and Texas during summer and autumn 2021–2022 and removed the lapillus otolith, left primary pectoral fin ray, postcleithrum, urohyal bone, and anterior‐most pterygiophore of the dorsal fin from both Bighead and Silver carp. The structures (n = 1204) were either embedded in epoxy or thin‐sectioned and mounted on slides. Two readers estimated the age of the fish by using each structure and came to a consensus. Processing time was recorded from the onset of laboratory processing to the termination of polishing the cross sections for age estimation.ResultProcessing of otoliths was comparable to or faster than processing of the other structures and resulted in the highest between‐reader agreement. The lowest coefficients of variation in age estimation were represented using lapillus otoliths for Bighead Carp and postcleithra for Silver Carp. Our age bias plots indicated that all other structures underestimated age relative to the lapillus otoliths.ConclusionOur results indicated that using lapillus otoliths for age estimation of these species would have the highest between‐reader agreement and would incur no additional laboratory processing time. However, validation is needed to assess whether lapillus otoliths correctly age these species. From a management perspective, use of this structure would facilitate improved population comparisons.

Psilorhynchus kosygini, a new species of torrent minnow (Teleostei: Psilorhynchidae) from Nagaland, north-east India

ABSTRACT Psilorhynchus kosygini, a new species, is described from the Tepuiki River, a tributary of the Barak drainage in Nagaland, north-east India. The new species, belonging to the P. homaloptera species group, is characterised by possessing a unique pattern of 3–4 scales positioned along the mid-ventral region between the posterior base of the pelvic fin and the anal opening, body elongate with 41–42 scales along the lateral line, 14 scales in the pre-dorsal region, 8 scales around the caudal peduncle and 9–10 branched pectoral-fin rays. http://www.zoobank.org/urn:lsid:zoobank.org:pub:00002407-A5D2-40F5-BB6B-624F00676BA8

Using Fin Ray Elemental Signatures and Growth Zone Width to Estimate Onset of Sexually Maturity in Lake Sturgeon (Acipenser fulvescens)

Characterizing inter- and intra-population levels of variability in age at sexual maturation for long-lived fishes provides insight into year-class strength and recruitment dynamics, allowing for more effective management practices. Here we analyzed the ontogenetic chronology of pectoral fin ray annuli trace elemental concentration profiles as well as changes in annuli growth in Lake Sturgeon (Acipenser fulvescens) to determine onset of sexual maturity (OSM). Elemental concentrations and growth-zone width were used to build a random forest classification model to discriminate year-specific signatures to before or after OSM from 98 individual fin rays from both sexes across multiple populations and watersheds. The model demonstrated an overall accuracy of 98.8%. Ba was the most important variable related to OSM discrimination success followed by zone width, Pb, Mn, Mg, Zn, Cu, and Sr. Fin ray elemental concentrations began to increase at approximately age 24 (± 4.7) in females and 15 (± 3.1) in males while zone width decreased. This study implies that new applications for fin ray microchemistry are possible and could benefit future fisheries management strategies specifically by adding nonlethal or less invasive sampling techniques for evaluating OSM in sturgeon.

Taxonomy of freshwater gobies of the genus Rhinogobius (Oxudercidae, Gobiiformes) from central Vietnam, with descriptions of two new species.

Taxonomy of the genus Rhinogobius was investigated for the first time in Central Vietnam. Five species occurring in this region can be distinguished by shape of their head, number of pectoral-fin rays, vertebral counts, arrangements of scales and cutaneous sensory papillae, and coloration. Two species are described as new, Rhinogobius rong sp. nov. and R. nami sp. nov., and the remaining three were identified as R. taenigena, R. leavelli, and R. similis. Though the morphology of R. leavelli and R. similis differed slightly between localities, counts and measurements overlapped, and coloration was variable. This study tentatively identifies all of those populations as R. leavelli or R. similis, but further research using additional specimens from a wider geographic range is required to clear the identity of the Rhinogobius occurring in this region. Rhinogobius rong, R. similis, and R. leavelli are distributed in both Da Nang City and Thua Thien Hue Province, with the first two species occurring widely in coastal areas, and R. leavelli restricted to inland areas. On the other hand, Rhinogobius nami and R. taenigena occur only in inland areas of Da Nang City and Thua Thien Hue Province, respectively.

Evaluation of techniques for estimating the age and growth of known-age White Sturgeon

Abstract Objective Successful conservation and management of fishes require an understanding of their age and growth. However, methods for estimating the age and growth of long-lived fish species are difficult to validate. The Kootenai River basin has a decades-long mark–recapture program for endangered White Sturgeon Acipenser transmontanus. The mark–recapture history information for White Sturgeon allowed for the evaluation of fin rays for age and growth analysis. Methods Age was estimated from pectoral fin rays of known-age White Sturgeon (n = 162) to evaluate ageing accuracy and precision. Lengths were back-calculated using four models and measurements obtained from two fin ray transects (i.e., lateral and posterior). Result Between-reader agreement for White Sturgeon ages was 58.7%. Consensus age agreement with known ages was poor (30.7%) and decreased with age. Among the four back-calculation models, the Fraser–Lee model provided the lowest root mean square error and percent error. Estimates of mean back-calculated lengths at age derived from the Fraser–Lee model were similar between the two measurement transects. Back-calculated lengths at age were similar to known lengths at age. Conclusion Ageing of White Sturgeon using fin rays was unreliable, and accuracy decreased with fish age. Back-calculated lengths at age were accurate using measurements from fin rays of known-age fish. Length estimates from the two measurement transects were similar when using the Fraser–Lee method, suggesting that they may be used interchangeably.