Pelvic Fin Rays Research Articles

Morphological comparison of Delminichthys ghetaldii (Steindachner, 1882), D. adspersus (Heckel, 1843), D. jadovensis (Zupančič & Bogutskaya, 2002) and D. krbavensis (Zupančič & Bogutskaya, 2002), endemic species of the Dinaric karst, Croatia

The objectives of this study were to gain a new understanding of the morphology of four endemic Delminichthys species, to determine the presence of morphological differences among populations and species, and to reveal reductive characters that might be connected with underground migrations. Morphometric and meristic characters were measured and statistically compared between populations and species. The study was conducted in the Dinaric region of Croatia and Bosnia and Herzegovina in the year 2013. Interpopulation variability observed for body shape (all size-independent morphometric characters significantly differed among populations) could be a reflection of the varying ecological conditions, although it might also imply the isolation of populations belonging to the same species. The number of lateral line scales (21–37 in D. krbavensis, 47–63 in D. jadovensis, 52–74 in D. adspersus, 88–105 in D. ghetaldii) proved to be the best diagnostic character for the Delminichthys species. Nevertheless, differences among the species in the number of pectoral and ventral fin rays, colouration, appearance of the lateral line, position of the mouth and presence of the groove above the upper lip were also observed.

Climbing upstream: Multi-scale structural characterization and underwater adhesion of the Pulin river loach (Sinogastromyzon puliensis)

Hillstream fishes live in the current with high flow velocity and strong water impact. To survive in such environments, they evolved various adhesive apparatus and attachment mechanisms. In this study, we investigated the Pulin river loach (Sinogatromyzon puliensis) known for its ability to climb vertically against rapid torrent. The whole body forms a suction system, consisting of lips, overlapped pectoral and fused pelvic fins. The hierarchical structure of lips and fins was characterized by Scanning Electron Microscopy. Polygonal pad-like protrusions, called unculi, were found on the lips and micro-sized, needle-like unculi (setae) covered both pectoral and pelvic fin rays. Pull-off stress was measured to evaluate the adhesion capability of dead river loach to substrates with varying surface roughness and compared with commercial suction cups. Results showed that river loaches can adhere equally well to surfaces with varying roughness while suction cups fail to adhere to rough surfaces. Underwater adhesion was accomplished by three possible mechanisms: (1) unculi enhance friction force on substrates, (2) setae interlock with irregularities, and (3) setae seal the edge and prevent leakage. The specialized adhesion apparatus and capability of Pulin river loach could provide inspirations and design strategies for novel underwater adhesives and devices.

BIOMETRIC ANALYSIS OF THE ARTIFICIAL HYBRIDIZATION BETWEEN Pangasius djambal BLEEKER, 1846 AND Pangasianodon hypophthalmus SAUVAGE, 1878

It is really important, since the possible use of these pangasiid hybrids in aquaculture faces the problem of potential impact on wild population. Therefore, it is urgently needed to provide quick identification tools in the field. This study investigated morphological characters of Pangasius djambal and Pangasianodon hypophthalmus and their hybrids. A detailed morphological analysis using 32 morphometric measurements and five meristic counts was done on the hybridization of P. djambal and P. hypophthalmus. Morphometric analysis and meristic counts showed that the reciprocal hybrids have intermediate characters except for gill raker number in which lower than that of parental species. In general, the hybrids have tendency to be like P. hypophthalmus rather than P. djambal. The only typical character of P. djambal appeared on hybrids is teeth shape, both vomerine and palatine. It is clearly defined that the true hybrids have seven pelvic fin rays.

BIOMETRIC ANALYSIS OF THE ARTIFICIAL HYBRIDIZATION BETWEEN Pangasius djambal BLEEKER, 1846 AND Pangasianodon hypophthalmus SAUVAGE, 1878

It is really important, since the possible use of these pangasiid hybrids in aquaculture faces the problem of potential impact on wild population. Therefore, it is urgently needed to provide quick identification tools in the field. This study investigated morphological characters of Pangasius djambal and Pangasianodon hypophthalmus and their hybrids. A detailed morphological analysis using 32 morphometric measurements and five meristic counts was done on the hybridization of P. djambal and P. hypophthalmus. Morphometric analysis and meristic counts showed that the reciprocal hybrids have intermediate characters except for gill raker number in which lower than that of parental species. In general, the hybrids have tendency to be like P. hypophthalmus rather than P. djambal. The only typical character of P. djambal appeared on hybrids is teeth shape, both vomerine and palatine. It is clearly defined that the true hybrids have seven pelvic fin rays.

Squalius namak, a new chub from Lake Namak basin in Iran (Teleostei: Cyprinidae).

Squalius namak, new species, from the endorheic Lake Namak and Kavir basins in Iran, is distinguished from the species of the genus Squalius in the Persian Gulf and the southern Caspian Sea basins by having a wide and thick symphysial knob on the lower jaw, a convex posterior anal-fin margin, a bold, dark-grey or brown, roundish or crescent-shaped blotch at the posterior tip of each flank scale and orange caudal-, anal- and pelvic-fin rays in life. Squalius namak is also characterized by four fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region.

Description of a new species of Priolepis (Perciformes: Gobiidae) from the Red Sea, a new record of Priolepis compita, and a distributional range extension of Trimma fishelsoni.

A new species of Reefgoby, Priolepis melanops, is described from Al Lith, central Saudi Arabian coast of the Red Sea, on the basis of a single adult specimen. It is a distinctive species, and can distinguish from its congeners by the following characters: dorsal-fin rays VI + I,9, no elongate spines in first dorsal fin; anal-fin rays I,8; pectoral-fin rays 14-15, all unbranched; longitudinal scale series 25; no scales on the head or predorsal midline, sides of the nape scaled; a developed transverse pattern of the sensory papillae below the eye; fifth pelvic-fin ray unbranched, its length 47% length of fourth ray; body and most of head brownish orange, densely covered with melanophores; snout, lips, chin and chest black; iris black; fins translucent with narrow black stripe along base of each dorsal fin. Placement of the new species in Priolepis is based on the presence of characteristics currently associated with Priolepis rather than with Trimma. An individual of Priolepis compita Winterbottom was photographed in very shallow water on a reef flat at Sharm el Sheikh, at the entrance of the Gulf of Aqaba, and represents a new record for the Red Sea. The endemic Red Sea species Trimma filamentosus Winterbottom and T. fishelsoni Goren, previously know as far south as Jeddah, were collected at Al Lith, central Saudi Arabia, and represents the southernmost record for both species. Variation of P. compita and T. fishelsoni is noted and the cephalic sensory system of the latter is described for the first time. In addition, we report that records of Trimma tevegae Cohen & Davis from the Red Sea are based on misidentification. A key to distinguish the species of Priolepis and Trimma known from the Red Sea is provided.

Growth Model Selection and its Application for Characterizing Life History of a Migratory Bull Trout (Salvelinus confluentus)Population

Abstract Five growth models were evaluated for their effectiveness in characterizing growth of an isolated population of bull trout, Salvelinus confluentus, undergoing a long term cessation of harvest (1994–2005) in the North Fork Clearwater River, Idaho, above Dworshak Dam. To explore the dynamics of growth in migratory bull trout, one of the models, the von Bertalanffy model, was also fitted based on age estimates derived from annuli and growth increments on pelvic fin ray sections for three juvenile outmigration age groups. Among five growth models evaluated, four models fitted to the age-length data described the fish growth for ages 3 to 11 comparably well. Only a model that exhibited positive growth acceleration as age progressed fitted the data less effectively. Growth was significantly (P < 0.001) related to the age of outmigration from natal streams (1–3 years). Migratory bull trout were found to reach maturation at ages 4–6; the common age-4 maturation was younger than most comparable studies. A...

Trimma tevegae and T. caudomaculatum revisited and redescribed(Acanthopterygii, Gobiidae), with descriptions of three new similar species from the western Pacific.

A redescription and diagnosis of Trimma tevegae, based on 50 additional specimens from the type locality at Rabaul, New Britain is provided, and contrasted with the redescription and diagnosis of T. caudomaculatum, based on the type material and an additional 22 specimens from various western Pacific localities. Trimma tevegae may most easily be recognized by the lack of a blue stripe (dark in preservative) in the dorsal midline of the snout, and a short second spine in the first dorsal fin, reaching posteriorly to the origin or first few ray bases of the second dorsal fin. Trimma caudomaculatum can be identified by the blue stripe from the snout along the dorsal midline, the blue spots and stripes in front of the eye, on the opercle and beneath the eye (dark in preserved material), and the very elongate second dorsal spine, usually extending to beyond the end of the second dorsal fin. Three similar-looking new species are described. Trimma burridgeae and T. hollemani are morphologically very close to each other, differing mainly in the length of the second dorsal spine (to the posterior base of the second dorsal fin or beyond in T. burridgeae; to the anterior base of that fin in T. hollemani). These two species differ by over 9% of the bases of the COI gene. Trimma corerefum is the most distinctive of the species, differing in lacking a blue stripe on the dorsal surface of the snout, in the pigment pattern around the eye, in having fewer cephalic sensory papillae (free neuromasts) in rows d', ea, ep, f, r and ot, and in a shorter fifth pelvic fin ray (34-45% length of fourth pelvic ray). The morphological differences between the species are reinforced by the results of a barcode analysis of the COI gene, based on 105 specimens.

Varicus lacerta, a new species of goby (Teleostei, Gobiidae, Gobiosomatini, Nes subgroup) from a mesophotic reef in the southern Caribbean.

We describe a new species of goby, Varicus lacerta sp. n., which was collected from a mesophotic reef at Curacao, southern Caribbean. The new species is the tenth species of Varicus, all of which occur below traditional SCUBA depths in the wider Caribbean area. Its placement in the genus Varicus is supported by a molecular phylogenetic analysis of three nuclear genes and the mitochondrial gene cytochrome b. In addition, the new species has one anal-fin pterygiophore inserted anterior to the first haemal spine, which distinguishes Varicus species from most species in the closely related and morphologically similar genus Psilotris. Varicus lacerta sp. n. is distinguished from all other named species of Varicus by the absence of scales, having highly branched, feather-like pelvic-fin rays, and in its live coloration. We provide the cytochrome c oxidase I DNA barcode of the holotype and compare color patterns of all species of Varicus and Psilotris for which color photographs or illustrations are available. This study is one of several recent studies demonstrating the utility of manned submersibles in exploring the diversity of poorly studied but species-rich deep-reef habitats.

A name for the 'blueberry tetra', an aquarium trade popular species of Hyphessobrycon Durbin (Characiformes, Characidae), with comments on fish species descriptions lacking accurate type locality.

A new species of Hyphessobrycon is described from a tributary of the upper Rio Tapajós, Amazon basin, Mato Grosso, Brazil. Its exuberant colour in life, with blue to purple body and red fins, is appreciated in the aquarium trade. Characters to diagnose the new species from all congeners are the presence of a single humeral blotch, absence of a distinct caudal-peduncle blotch, absence of a well-defined dark mid-lateral stripe on body, the presence of 16-18 branched anal-fin rays, nine branched dorsal-fin rays and six branched pelvic-fin rays. A brief comment on fish species descriptions solely based on aquarium material and its consequence for conservation policies is provided.

Growth pattern and natural mortality of elephant fishes (Mormyrus kannume, Mormyridae) in the Damietta branch of Nile, Egypt

The present study sheds light on the growth pattern of the elephant snout fish (Mormyrus kannume, Mormyridae) in the Damietta branch of the Nile during the period from January to December 2010. This is done through studying the biometric characters, length–weight relationship, condition factors, growth performance index as well as the natural mortality. The linear regression for 15 morphometric characters in total length and 4 morphometric characters in head length was applied. The higher coefficient of the characters’ determinations which fit best was also applied. Five meristic characters were determined (dorsal fin rays, 49–69; pectoral fin rays, 12–15; ventral fin rays, 6; anal fin rays, 17–21 and vertebrae, 49–52). Fish length varied between 14.0cm and 43.0cm TL with a modal length range from 19 to 22cm representing 61.36% of the fish sample. A length–weight relationship using the total weight was found to be LogW=−2.2218+3.063LogL (R2=0.997) and using the gutted weight was LogW=−2.1549+3.003LogL (R2=0.995) hence exhibiting isometric growth. The average condition factors for different lengths were 0.76±0.06. The chi-square of the overall sex ratio (male:female=1:0.42) was significant at P<0.01. The life span of this species is five years, with individuals of two years of age dominating the population. The different growth parameters were estimated at (K=0.141, to=−0.271, L∞=80.65cm, W∞=4151g, ФL=2.96 and ФW=1.56). The natural mortality was 0.34, the M/K ratio was 2.38 and the variation of M by age model was also computed.

Description of Karaganops n. gen. perratus (Daniltshenko 1970) with otoliths in situ, an endemic Karaganian (Middle Miocene) herring (Clupeidae) in the Eastern Paratethys

Karaganops is established as a new fossil genus of the family Clupeidae, subfamily Clupeinae, to encompass the nominal species Sardinella perrata Daniltshenko 1970 from the Karaganian of southern Russia. Karaganops belongs to the group of genera characterized by the presence of two elongated rays at the end of the anal fin, which further includes Sardinella, Clupeonella, Sardina, Sardinops, and Harengula. It differs from Sardinella amongst others in the absence of tooth plates on the palatines and pterygoids, the presence of seven branchiostegal rays (vs. six), the presence of two epurals (vs. three) and the presence of nine pelvic fin rays (vs. 7–8). Otoliths found in situ further support the separation of Karaganops from Sardinella and related genera and add evidence for a second, otolith-based species—Karaganops komochtitziensis (Strashimirov 1985)—from the Middle Sarmatian of Bulgaria. Karaganops is thought to represent an endemic clupeid genus of the Eastern Paratethys that evolved during the mid-Miocene Karaganian ecological crisis in the basin. An otolith found in situ in a skeleton of Sarmatella doljeana (Kramberger 1883) from the Early Sarmatian of Belgrade, Serbia and an otolith interpreted to be associated with another fossil clupeid genus and species—Sarmatella tsurevica (Baykina 2012)—from the Early Sarmatian of the Caucasus facilitates correlation with previously described otolith-based species. It demonstrates that Sarmatella may not represent a primary endemic of the Paratethys and that its fossil record reaches back in time to Early Miocene and possibly Late Oligocene in the North Sea Basin.

A New Species ofHyphessobrycon(Characiformes: Characidae) from the Upper Rio Juruena Basin, Central Brazil, with a Redescription ofH. cyanotaenia

A new species of Hyphessobrycon is described from the Rio Papagaio, a tributary of the Rio Juruena, Rio Tapajos basin, Brazil. The new taxon can be distinguished from its congeners by having a well-defined and relatively narrow dark midlateral stripe on body extending from the upper half of the posterior margin of the eye to the middle caudal-fin rays, absence of a humeral blotch, 16–19 branched anal-fin rays, 2–4 maxillary teeth, six branched pelvic-fin rays, and the absence of dark pigmentation crossing the eye. Hyphessobrycon cyanotaenia, a species described from few specimens from the aquarium trade without precise locality, is redescribed herein based on extensive material, and its known distribution is discussed and rectified from the original description.

A new species of Leptoderma Vaillant, 1886 (Osmeriformes: Alepocephalidae) from the Pacific coast of Central America.

A new species of Leptoderma Vaillant, 1886 is described from a single specimen trawled at 1368-1406 m depth off El Salvador, Central America, tropical eastern Pacific. Leptoderma ospesca n. sp. can be readily distinguished from its congeners by the following combination of characters: dermal papillae absent along the lateral line, pectoral-fin rays 6, pelvic-fin rays 5, pre-dorsal length 54.9% of SL, both dorsal and anal fins separated from the caudal fin, dorsal- and anal-fin rays long, procurrent caudal-fin rays numerous and extending far forward on caudal peduncle, caudal-fin rays 16, and total pre-ural vertebrae 60. A key to the species of the genus is presented.

Comparative morphology of bony hooks of the anal and pelvic fin in six neotropical characid fishes (Ostariophysi: Characiformes)

The morphology of bony hooks on anal-fin and pelvic-fin rays in six neotropical characid fish (Astyanax fasciatus, A. lacustris, Hyphessobrycon bifasciatus, H. itaparicensis, Compsura heterura and Serrapinnus heterodon) representing different reproductive modes (inseminating and externally fertilizing) was analysed with a particular focus on the form, distribution, development and orientation of bony hooks of the male anal-fin and pelvic-fin rays.When present bony hooks of the anal-fin and pelvic-fin rays in adult males represented a permanent structure and its development is likely closely related to the reproductive phase. Bony hooks were found on anal-fin and pelvic-fin rays in A. lacustris, C. heterura, H. itaparicensis and S. heterodon whereas A. fasciatus and H. bifasciatus showed bony hooks only on the anal-fin rays. The absence of pelvic-fin rays may be related to hormonal factors and linked to the courtship behavior. Despite their reproductive mode, the bony hooks on anal-fin and pelvic-fin rays were positioned along the posterolateral border. On pelvic-fin rays, the distal tips of the bony hooks were directed towards the anterior fin ray border in inseminating or non-inseminating species. On the anal-fin rays, the distal tips of the hooks were morphologically different in inseminating and externally fertilizing species. Inseminating characids such as C. heterura exhibited a distinct morphological arrangement of hooks exclusively present on pelvic-fin rays similar to the structures found in inseminating species. The number of bony hooks on anal-fin rays was higher only among the Cheirodontinae such as C. heterura and S. heterodon regardless of their reproductive mode. Apparently the presence and morphology of bony hooks on fin rays represent an important data source for phylogenetic, reproductive and behavioral studies of characid fish.

A comparison of different structures and methods for estimating age of northern-form Dolly Varden Salvelinus malma malma from the Canadian Arctic

Assessment of anadromous northern-form Dolly Varden Salvelinus malma malma in the Western Canadian Arctic requires reliable methods for estimating ages. Additionally, conservation efforts warrant determining whether fin rays provide a non-lethal alternative to otoliths. Precision and bias of whole and sectioned otoliths, and sectioned pectoral and pelvic fin rays were examined. Two age readers with different levels of experience ageing this species read each structure three times. Coefficient of variation (CV) was calculated to measure precision, and age bias plots were created for each method of preparation/structure within and between readers. The experienced reader demonstrated the highest precision with sectioned otoliths (CV = 1.6 %) followed by whole otoliths (CV = 4.2 %) while pectoral and pelvic fins were the lowest, CV = 7.7 % and 7.5 %, respectively. The age bias plot showed little difference between whole and sectioned otoliths, although greater imprecision/bias was evident for whole otoliths at age ≥9. Compared to otoliths, fin rays produced younger age estimates starting at 5 years; however, pelvic fins were more biased towards younger estimates than pectoral fins. The less experienced reader had greater inconsistencies, tending to overage younger and underage older samples for all methods compared to the more experienced reader, underscoring the importance of experience when estimating age for this species. We conclude that both types of fin rays are a poor non-lethal alternative to otoliths for fish ≥5 years and recommend an experienced ager could use whole otoliths up to age 8 and sectioned otoliths for fish ≥9 years (>500 mm fork length).

Cover Image

COVER PHOTOGRAPH: Lateral view of completely scaled juvenile pelvic fin ray. From Postembryonic staging of wild‐type goldfish, with brief reference to skeletal systems, Ing‐Jia Li, Chun‐Ju Chang, Shi‐Chieh Liu, Gembu Abe and Kinya G. Ota, Developmental Dynamics 244:1485–1518.Read the full article at DOI: 10.1002/dvdy.24340

Redescription of Nezumia infranudis (Gilbert & Hubbs, 1920), with the first record of the species from the Eastern Indian Ocean (Actinopterygii: Gadiformes: Macrouridae)

Nezumia infranudis is redescribed from the holotype and an additional specimen collected from the Timor Sea at a depth of 610–690 m. It belongs to the Nezumia spinosa group (herein defined) and is most similar to the Indo-West Pacific N. spinosa. Nezumia infranudis is distinguished from other congeners by the following combination of features: pelvic-fin rays 11; body scales covered with long, reclined, needle-like spinules densely scattered over exposed portion; underside of head almost completely naked, with prominent sensory pores; teeth in broad bands in both jaws; snout long (31–32% of head length (HL)), protruding well beyond upper jaw; second spinous ray of first dorsal fin greatly elongated (height of first dorsal fin 158–166% HL); no prominent dark band encircling trunk; first dorsal fin almost uniformly blackish. The first report of N. infranudis in the Indian Ocean represents the only confirmed record of the species since its original description. A key to species of the N. spinosa group is provided.

Two new dwarfgobies (Teleostei: Gobiidae) from the Ryukyu Islands, Japan: Eviota flavipinnata and Eviota rubrimaculata.

Two new species of Eviota from Yoron Island, the Ryukyu Islands, Japan, are described. Both species belong to the cephalic sensory-canal pore system pattern 2 (lacking only the H [IT] pore); have some pectoral-fin rays branched; have a dorsal/anal-fin formula of 9/8; no dark spot over the ural centrum; no prominent distinct dark spots on the pectoral-fin base; no postocular spots; and no strong dark spots on the caudal fin. The species share the most characters with E. afelei, E. bimaculata and E. punctulata, but differ from Eviota afelei and E. punctulata by having two versus three dark marks over the anal-fin base, and from Eviota bimaculata by lacking the two dark, prominent occipital spots present in that species. Both species differ from all other described species of Eviota in fresh coloration. Eviota flavipinnata has bright golden-yellow dorsal fins and an orange anal fin, and a fifth pelvic-fin ray that is 12% the length of the fourth ray. Eviota rubrimaculata has clear dorsal fins with red spots, large red spots on the body, and lacks the fifth pelvic-fin ray.

Mahseers genera Tor and Neolissochilus (Teleostei: Cyprinidae) from southern Vietnam.

Two new species and two new basin records of mahseers in the genera Tor and Neolissochilus are described from the upper Krong No and middle Đồng Nai drainages of the Langbiang Plateau in southern Vietnam. These new species and new records are known from streams and rivers in montane mixed pine and evergreen forests between 140 and 1112 m. Their populations are isolated in the Sre Pok River of the Mekong basin, the middle of the Đồng Nai basin, and the An Lão River. Both new species are differentiated from their congeners by a combination of the following characters: 23-24 lateral scales, 9-10 predorsal scales, 2/7 or 1/8 pelvic-fin rays, mouth position, median lobe of lower lip, rostral hood, colour in life and by divergent mitochondrial DNA. Tor mekongensis sp. nov. is differentiated from Tor dongnaiensis sp. nov. by the number of transverse scale rows (3/1/2 vs. 4/1/2), number of pelvic-fin rays (2/7 vs. 1/8), a blunt rostral hood vs. pointed, caudal-fin lobes that are equal vs. unequal, and by mitochondrial DNA (0.7% sequence divergence). Molecular evidence identifies both species as members of the genus Tor and distinct from all congeners sampled (uncorrected sequence divergences &gt;1.9% for all Tor species for which homologous COI sequences are available). Tor sinensis is recorded in the Krong No and the Sre Pok rivers, further south of its known distribution. Polymorphism is described in Neolissochilus stracheyi with a Tor-like morph and a Neolissochilus-like morph.