Fin Origin Research Articles

A new pufferfish (Teleostei, Tetraodontidae) from the Middle Miocene of St. Margarethen, Austria

Articulated skeletal remains of tetraodontid pufferfishes are rather rare in the fossil record. To date, the only known relatively entire fossil pufferfishes are the few specimens belonging to the extinct genera Eotetraodon and Archaeotetraodon, from the Eocene and Oligo-Miocene, respectively. A new genus and species of tetraodontid pufferfish, Leithaodon sandroi gen. et sp. nov., is described herein from the Middle Miocene fish-bearing corallinacean limestone of St. Margarethen, Burgenland, eastern Austria. This new taxon is based on a single, nearly complete specimen that exhibits a unique combination of features (sphenotic articulating with the supraoccipital, lateral ethmoid in contact with the palatine, anal fin origin slightly behind the posterior end of the dorsal fin base, 11(12) dorsal fin pterygiophores, but only six anal fin pterygiophores, and slender elongate ventral postcleithrum) that distinguish it from all other tetraodontids, fossil and extant. The paleoecology of this new taxon also is discussed.

Description of a new deep-sea eelpout Pachycara matallanasi sp. nov. from the Solomon Sea (western South Pacific Ocean)

A new species of zoarcid fish, Pachycara matallanasi, is described. During the Danish Galathea 3 expedition, on 28 December 2006, six specimens of Pachycara Zugmayer, 1911 were collected from depths of 4350–4450 m. The new species is the second member of the genus in the western South Pacific Ocean. Pachycara matallanasi sp. nov. can be distinguished from its congeners by a combination of the following characters: body without scales; pelvic fin absent; lateral line mediolateral; dorsal fin origin associated with vertebrae 5–6 with 0–1 free predorsal pterygiophores; total vertebrae 103–108; smooth ceratohyal–epihyal articulation; post-temporal with well-developed ventral ramus; coracoid with a posterior strut and a small foramen.http://zoobank.org/urn:lsid:zoobank.org:pub:B61D0421-8CF3-46E5-BCE0-20E12E3ED69A

The origins of adipose fins: an analysis of homoplasy and the serial homology of vertebrate appendages

Adipose fins are appendages found on the dorsal midline between the dorsal and caudal fins in more than 6000 living species of teleost fishes. It has been consistently argued that adipose fins evolved once and have been lost repeatedly across teleosts owing to limited function. Here, we demonstrate that adipose fins originated repeatedly by using phylogenetic and anatomical evidence. This suggests that adipose fins are adaptive, although their function remains undetermined. To test for generalities in the evolution of form in de novo vertebrate fins, we studied the skeletal anatomy of adipose fins across 620 species belonging to 186 genera and 55 families. Adipose fins have repeatedly evolved endoskeletal plates, anterior dermal spines and fin rays. The repeated evolution of fin rays in adipose fins suggests that these fins can evolve new tissue types and increased structural complexity by expressing fin-associated developmental modules in these new territories. Patterns of skeletal elaboration differ between the various occurrences of adipose fins and challenge prevailing hypotheses for vertebrate fin origin. Adipose fins represent a powerful and, thus far, barely studied model for exploring the evolution of vertebrate limbs and the roles of adaptation and generative biases in morphological evolution.

The lateral mesodermal divide: an epigenetic model of the origin of paired fins

By examining development at the level of tissues and processes, rather than focusing on gene expression, we have formulated a general hypothesis to explain the dorso-ventral and anterior-posterior placement of paired appendage initiation sites in vertebrates. According to our model, the number and position of paired appendages are due to a commonality of embryonic tissue environments determined by the global interactions involving the two separated layers (somatic and visceral) of lateral plate mesoderm along the dorso-ventral and anterior-posterior axes of the embryo. We identify this distribution of developmental conditions, as modulated by the separation/contact of the two LPM layers and their interactions with somitic mesoderm, ectoderm, and endoderm as a dynamic developmental entity which we have termed the lateral mesodermal divide (LMD). Where the divide results in a certain tissue environment, fin bud initiation can occur. According to our hypothesis, the influence of the developing gut suppresses limb initiation along the midgut region and the ventral body wall owing to an "endodermal predominance." From an evolutionary perspective, the lack of gut regionalization in agnathans reflects the ancestral absence of these conditions, and the elaboration of the gut together with the concomitant changes to the LMD in the gnathostomes could have led to the origin of paired fins.

A New Species of Cyprinid Fish of Genus Opsariichthys from Ky Cung-Bang Giang River Basin, Northern Vietnam with Notes on the Taxonomic Status of the Genus from Northern Vietnam and Southern China

Opsariichthys duchuunguyeni, a new species of cyprinid fish from Ky Cung-Bang Giang river basin, northern Vietnam, is described. It is characterized by the following unique combination of features: short maxillary extending; 12-15 rounded tubercles on lower jaw; 11-12 crossbars on body; pectoral fin reaching the pelvic fin origin in adult male; lateral- line scales comprising 41; scales above lateral-line 8; scales below lateral-line 3. Moreover, the genetic differentiation and a diagnostic key of the new species and other congeners are given in this paper for discussion about taxonomic status of the genus Opsariichthys from Vietnam and nearby geographical regions, southern China and Taiwan.

제주도 남방해역에서 채집된 제주바다뱀(Ophichthus asakusae) 엽상자어(Leptocephalus)의 첫 형태기재

Two leptocephali [total length (TL) 68.2-80.5 mm] from the family Ophichthidae, collected from the waters south of Jeju Island, Korea, were identified using morphology. The two ophichthid leptocephali were identified as belonging to the genus Ophichthus based on morphological characters: 131-132 myomeres; nine gut swellings; dorsal fin origin above the middle of the body; five postanal pigments present from the anus to the caudal margin. Ultimately, both leptocephali were identified as Ophichthus asakusae, as the total number of myomeres was consistent with those of adult O. asakusae. Here, we first describe the morphological characteristics of the O. asakusae leptocephalus, and suggest diagnostic characters for leptocephali belonging to the genus Ophichthus.

Sinocyclocheilus xichouensis, a new species of golden-line fish from the Red River drainage in Yunnan, China (Teleostei: Cypriniformes)

In the present study, a new species of the genus Sinocyclocheilus Fang 1936, Sinocyclocheilus xichouensis, was described from the Ganhaizi tributary of Chouyang River, Red River drainage, located in southeast Yunnan, China. This species has normal eyes and a strong dorsal spine with serrations on the lower 3/5 part. In general, this species is similar in morphology to S. macrophthalmus, S. guishanensis, S. angustiporus, S. lateristritus, S. qiubeiensis, S. grahami, S. qujingensis, S. maculatus and S. purpureus distributed in the Nanpanjiang River, and S. qiubeiensis distributed in the Red River. It is distinguished from S. macrophthalmus by possessing fewer than 9 gill rakers. However, S. xichouensis can be distinguished from S. guishanensis by its interorbital width/SL of 8.1~9.9%, rostral barbels extended to posterior margin of eye and maxillary barbels extended to posterior preopercular. It is distinct from S. lateristritus by dorsal-fin origin opposite of pelvic fin origin, with no a black stripe along the lateral line. It is distinguished from S. grahami by 74~88 lateral-line scales, 20 scale rows above the lateral line, and 16 scale rows below the lateral line. It is distinguished from S. qujingensis by a curved lateral line, 74-88 lateral-line scales, 48 circumpeduncular scales. It can be distinguished from S. yimenensis by the ratio of predorsal length, dorsal-fin base length, preanal length, anal fin length, prepectoral length, caudal-peduncle length and lower jaw length to SL, 47.1%-53.7%, 12.8%-15.8%, 66.0%-71.0%, 13.7%-17.1%, 26.0%-29.5%, 19.3%-24.7%, 4.7%-7.0%, respectively. It is distinguished from S. maculatus and S. purpureus by possession of lateral line and scaled body and distinguished from S. angustiporus and S. qiubeiensis by 35~39 predorsal scales, 6 gill rakers, and interorbital width/SL of 8.1%-9.9%.

Morphological and molecular variation in Synaphobranchus eels (Anguilliformes: Synaphobranchidae) of the Mid-Atlantic Ridge in relation to species diagnostics

Synaphobranchus eels are difficult to identify at species level. Previous taxonomic studies show several inconsistencies concerning the diagnostic characters of Synaphobranchus kaupii Johnson, 1862 and Synaphobranchus affinis Gunther, 1877. One hundred and eleven specimens from the Mid-Atlantic Ridge and a type specimen of S. affinis were examined morphologically, and the DNA barcode region of the mitochondrial COI gene was sequenced from 58 of these specimens. The results of this examination showed an ontogenetic change in most morphometric characters and that most of the previously used diagnostic characters—namely, dorsal fin origin in relation to the vent, predorsal length, scale shape and pattern, and dentition—cannot distinguish between the species S. kaupii and S. affinis. The type specimen of S. affinis may represent a member of a species that closely resembles S. kaupii morphologically, separable by having a lower number of vertebrae, dorsal fin rays, and anal fin rays.

Body wall development in lamprey and a new perspective on the origin of vertebrate paired fins

Classical hypotheses regarding the evolutionary origin of paired appendages propose transformation of precursor structures (gill arches and lateral fin folds) into paired fins. During development, gnathostome paired appendages form as outgrowths of body wall somatopleure, a tissue composed of somatic lateral plate mesoderm (LPM) and overlying ectoderm. In amniotes, LPM contributes connective tissue to abaxial musculature and forms ventrolateral dermis of the interlimb body wall. The phylogenetic distribution of this character is uncertain because lineage analyses of LPM have not been generated in anamniotes. We focus on the evolutionary history of the somatopleure to gain insight into the tissue context in which paired fins first appeared. Lampreys diverged from other vertebrates before the acquisition of paired fins and provide a model for investigating the preappendicular condition. We present vital dye fate maps that suggest the somatopleure is eliminated in lamprey as the LPM is separated from the ectoderm and sequestered to the coelomic linings during myotome extension. We also examine the distribution of postcranial mesoderm in catshark and axolotl. In contrast to lamprey, our findings support an LPM contribution to the trunk body wall of these taxa, which is similar to published data for amniotes. Collectively, these data lead us to hypothesize that a persistent somatopleure in the lateral body wall is a gnathostome synapomorphy, and the redistribution of LPM was a key step in generating the novel developmental module that ultimately produced paired fins. These embryological criteria can refocus arguments on paired fin origins and generate hypotheses testable by comparative studies on the source, sequence, and extent of genetic redeployment.

A new late neogene genus of roakers (Perciformes, Sciaenidae) from the Eastern Black Sea Region

The roaker species (Sciaenidae) Sciaena impropria Gabelaia, 1976 from the Lower Pliocene (?) of Abkhazia is assigned to a new genus, Carnevalella gen. nov. This genus essentially differs from other sciaenid fishes in the greater number of supraneurals and vertebrae, the posterior shift of the dorsal fin origin, and the fusion of the fourth hypural with the terminal centrum. An incomplete roaker skeleton found in the Upper Maeotian (Upper Miocene) of the Taman Peninsula (Krasnodar Region) is assigned to the same genus. The Maeotian roaker is described as a new species, C. (?) tmutarakanica sp. nov. Morphological peculiarity of the genus Carnevalella gen. nov. justifies its allocation to a new subfamily, Carnevalellinae subfam. nov.

Schistura porocephala, a new nemacheilid loach from Koladyne basin, Mizoram, India (Teleostei: Nemacheilidae)

Schistura porocephala, a new nemacheilid species, is described from a stream that drains into the Mat River (Koladyne basin), India. It is characterized by the presence of prominent pores in the cephalic lateral line system; an incomplete lateral line; 20–23 thin dark olivaceous bars on the body, often bifurcated from the dorsolateral region; a depressed head and body anterior to the dorsal fin origin; and an elongated suborbital flap arising in front of the nostril and extending to the anterior one-third of the eye diameter in males.

Acquisition of the paired fins: a view from the sequential evolution of the lateral plate mesoderm

The origin of paired fins has long been a focus of both paleontologists and developmental biologists. Fossil records indicate that the first pair of fin-like structures emerged in the body wall of early vertebrates. However, extant agnathan lampreys and hagfishes lack paired fins, and thus it has been difficult to determine the developmental processes underlying the ancestral acquisition of paired fins in vertebrates. Fortunately, recent advances in our knowledge of the developmental mechanisms of the lateral plate mesoderm among different taxa have provided clues for understanding the evolutionary origin of vertebrate paired appendages.

A new fish species of the walking snakehead group, the genus Channa (Channidae, Perciformes) in Vietnam

Channa longistomata sp. n. (Figs. 1, 2) Samples: 12 fish samples, L = 92-156 mm, Lo = 82-132 mm. Holotype: Sample code H.Na 011.04.001. L = 153 mm; Lo = 124 mm, collected at Tam Chuc lake, Ba Sao town, Kim Bang district, Ha Nam province, dated 21/04/2011. Paratypes: 5 samples, sample code H. Na.011.04.002. L = 132 mm. Lo = 106 mm, collected at Tam Chuc lake, Ba Sao town, Kim Bang district, Ha Nam province, dated 21/042011. Sample code H.B.65.11.011 L = 152 mm, Lo = 125 mm; H.B.65.11.012, L = 156 mm, Lo = 132 mm; H.B.65.11.013, L = 144 mm, Lo = 123 mm và H.B.65.11.014, L = 130 mm, Lo = 110 mm collected at Thac Bo, Da Bac district, Hoa Binh province, dated 20/11/1965. Samples preseved at Fish Museum of Research Institute for Aquaculture No.I, Bac Ninh. Diagnosis: Mouth arched, depth and narrow, mouth length wider than mouth width. Incision of lip along and little over the margin of eye equal eyes diameters origin. The dorsal fin origin in front of pelvic fin origin. The distant from pelvic fin origin to annal fin equal to meeting point of 2 gill arches. Especially toungue flat, thin and it has waist of middle toungue and small round proglossis. Description: Body length, the cylinder from the back side up gradually of high body close to the body thickness. The depth of caudal peduncle is short and height. The head is relative flat. Short snout. Round eyes located on the half first part of the head. Distances between 2 eyes were wide and relative flat. Mouth arched depth and narrow, mouth length wider than mouth width. Tougue flat thin and it has waist of middle toungue and small round of proglossis. (figs. 2a, b, c, d). Fins: D = 33 – 35; A = 22 -23; P = 14 – 15; V = 1,4 -5; C = 12; Scales: 42[...]46, scales around caudal peduncle =18, Lo = 5,48H = 3,8T T = 4,63Ot = 7,18O = 3,07 OO. OO = 2,33 O. H = 1,58 h. Fins of dorsal and anal are long. Dorsal fin origin in front of pelvic fin origin. The distant from pelvic fin origin to anal fin origin equal its to the start meeing point of 2 gill archs. Caudal fin shaped round of ending. All fins are soft. Head and body covered by scale. Lateral line discontinues which interrupted at the middle. Coloration: Color of body gray, no bar. Dorsal fin, annal fin and caudal fin have its outer of red-pink or spark yellow (white when preserved). Pectoral fins have from 3 to 5 black bars. Remarks: C. longistomata sp. n. distinguished from other species of C. gachua (Hamilton) and C.orientalis Bloch & Schneider by the combination of the following characters: mouth arched depth and narrow. The mouth length is bigger than the mouth width. The incision lip along reaching after the margin of eye which equals the eye diameter. Dorsal fin origin in front of pelvic fin origin. Toungue flat and its middle waist narrow, small round of proglossis. Two species C. gachua (Hamilton) and C. orientalis Bloch & Schneider have mouth arched shallow and wide, mouth length smaller than mouth width. The incision lip along reaching middle of eye or a little over margin of eye. Dorsal fin origin after or opposite of pelvic fin origin. Toungue flat and no waist, triangle long, small pointed of proglossis (C. gachua) or flat round of proglossis (C. orientalis). Distribution: Provinces of Da river basin (Dien Bien, Lai Chau, Son La and Hoa Binh) and distribution in lakes near regions of lime mountains of Ha Nam and Ninh Binh. Etymology: Channa longistomata was named according to specific characteristics with a long mouth which is different with the other similar species.

A new species of grenadier, genus Macrourus (Teleostei, Gadiformes, Macrouridae) from the southern hemisphere and a revision of the genus

A new Macrourus species from the southern hemisphere is described. It was first recognised from the Ross Sea, Antarcticaafter specimens sampled during the International Polar Year in 2008 showed significant genetic differences (C01) amongthose initially identified as M. whitsoni (Regan). M. caml sp. nov. has 8 (rarely 7 or 9) pelvic fin rays, a band (2–3 rows)of small uniform-sized teeth in the lower jaw, lacks an outer row of enlarged teeth in the upper jaw, 30–40 scales in a di-agonal row from anal fin origin to lateral line, ventral surface of the head is mostly scaled, except for scaleless areas an-terior to the mouth and on the anterior half of the lower jaw. M caml sp. nov. is large, reaching at least 890 mm TL andappears to be abundant. Numerous specimens caught by commercial bottom longline vessels fishing in the Ross Sea areheld at Museum of New Zealand Te Papa Tongarewa, Wellington New Zealand. All five species of Macrourus (M. ber-glax, M. caml, M. carinatus, M. holotrachys, and M. whitsoni) are compared and illustrated, based on examination of specimens, and a key to species is provided.

Hemiodus langeanii (Characiformes: Hemiodontidae), a new species from rio Amana, rio Maués-Açú drainage, Amazon basin, Brazil

Hemiodus langeanii, new species, is described based on 20 specimens collected in the rio Amana, a tributary of rio Maués-Açú, rio Amazonas drainage, Brazil. The new taxon can be distinguished from its congeners by its high body (27.1-35.3%, average 32.3% SL vs. 18.8-28.5% in remaining species). The new species also exhibits a large lateral dark spot that is equal to, or greater than, the eye diameter (vs. smaller in remaining species except for H. microlepis). The lack of conspicuous lateral stripe or transverse bands and the low lateral line scales count (68-74) distinguish H. langeanii from some similar species in the genus (scale counts: 94-123 in H. argenteus, 124-148 in H. microlepis, 86-99 in H. orthonops and 77-92 in H . parnaguae). Finally, the new species can be differentiated from H. unimaculatus (which overlaps in the number of lateral line scales) by the higher number of scales between the lateral line and the pelvic fin origin (9-10 vs. 4-7, respectively), which are similar sized above and below lateral line (vs. scales larger bellow the lateral line in H. unimaculatus).

Saurida golanii, a new deep water lizardfish (Pisces: Synodontidae) from the Gulf of Aqaba, northern Red Sea

Saurida golanii sp.nov. is described on the basis of eight specimens collected from bottom-set trammel nets in deep water (200–500 m) off Eilat, in the Gulf of Aqaba, northern Red Sea. The new species is characterised by the following combination of characters: lateral-line scales 53–56; transverse scale rows 4½/5½; long pectoral fins (extending beyond a line from origin of pelvic fins to origin of dorsal fin); caudal peduncle compressed (depth greater than width); and pelvic fins unpigmented.

A new blind loach, Oreonectes elongatus sp. nov. (Cypriniformes: Balitoridae) from Guangxi, China

A new loach, Oreonectes elongatus sp. nov. is described based on collections from Mulun Township, Huanjiang County, Guangxi in China. It is distinguished from its congeners by the combination of the following characters: most elongate body (body depth/SL 8.62–10.68%), blind, a forked caudal fin, obvious adipose dorsal crest and ventral crest; entire body naked and de-pigmented. Although the new species has a similar distribution with O. macrolepis, it can be distinguished by scales (absent in O. elongatus vs. present in O. macrolepis), shape of snout (elongate vs. round), the opposite position of the dorsal and pelvic fins origins (behind vs. front). The new species shares the same possession of dorsal and ventral crests, a forked caudal fin, eyeless, naked body and incomplete lateral line with O. translucens, but can be distinguished from the latter by caudal fin crest (more developed and translucent in O. translucens), longer anterior nostril tube and barbel, extreme of pectoral fin reaching 2/3 of the distance between origin of pectoral and pelvic fins, more vertebrae (4 + 38–39 vs. 4 + 32).

A new goatfish, Upeneus seychellensis sp. nov. (Mullidae), from the Seychelles Bank, with remarks on Upeneus guttatus and a key to Western Indian Ocean Upeneus species

The mullid genus Upeneus is highly diverse, with a considerable number of new species found only recently. Based on 16 specimens of Upeneus collected at the southeastern edge of the Seychelles Bank, a large oceanic platform in the Western Indian Ocean, a new species, Upeneus seychellensis, is described. Comparisons with and among populations of the closely related U. guttatus are made. By integration of an extensive, comparative data set consisting of 50 morphometric and meristic and several colour characters obtained from 25 additional Upeneus species, an updated key for the 18 Western Indian Ocean species is provided. The new species can be distinguished from all other congeners of the japonicus-species group, a complex of species with seven dorsal-fin spines, by a combination of number of pectoral fin rays and gill rakers, body depth at anal fin origin, caudal peduncle depth, anal fin size, first dorsal-fin height and colour of the lower caudal-fin lobe. Co-occurring specimens of U. guttatus are considerably differentiated in morphology and colour from other Indian Ocean populations and this was also found for a single specimen from the Gulf of Suez. These results indicate isolation and the formation of local adaptation in more remote areas of the Indian Ocean, but the influence of phenotypic plasticity also needs to be considered.

A new genus and two new species of Stevardiinae (Characiformes: Characidae) with a hypothesis on their relationships based on morphological and histological data

Lepidocharax, new genus, and Lepidocharax diamantina and L. burnsi new species from eastern Brazil are described herein. Lepidocharax is considered a monophyletic genus of the Stevardiinae and can be distinguished from the other members of this subfamily except Planaltina, Pseudocorynopoma, and Xenurobrycon by having the dorsal-fin origin vertically aligned with the anal-fin origin, vs. dorsal fin origin anterior or posterior to anal-fin origin. Additionally the new genus can be distinguished from those three genera by not having the scales extending over the ventral caudal-fin lobe modified to form the dorsal border of the pheromone pouch organ or to represent a pouch scale in sexually mature males. In this paper, we describe these two recently discovered species and the ultrastructure of their spermatozoa.

Variación morfológica de las especies de Astyanax, subgénero Zygogaster (Teleostei, Characidae)

The diverse Neotropical fish genus Astyanax inhabits a variety of aquatic environments. As with other species in this genus, the taxonomic status and phylogenetic relationships of species of this subgenus remain largely undetermined. Based on 354 individuals, we analyzed the morphological variation of four species of the subgenus Zygogaster (A. atratoensis, A. caucanus, A. filiferus, and A. magdalenae) using procrustes analysis and compared findings with two species of the sister group: subgenus Poecilurichthys (A. orthodus and A. superbus). The PCA (Principal Component Analysis) and CVA (Canonical Variates Analysis) showed morphological affinity between the subgenera and indicated variance in body depth, anterior trend of dorsal fin origin and humeral spot, depression on the dorsal surface of the skull, and ventral displacement of the orbit and snout. The variation in these structures may provide evidence supporting adaptive speciation as an alternative to speciation driven by geographical isolation.