Supraorbital Pores Research Articles

A new Congrid eel, Rhynchoconger smithi sp. nov. (Anguilliformes: Congridae), from the Bay of Bengal, India

A new Conger eel species is described based on four specimens collected from Petuaghat fishing harbour, West Bengal, India. The combination of morphological characters and molecular data are discordant with the seven congeners currently recognized. Rhynchoconger smithi sp. nov. can be distinguished by having head smaller than trunk; pre-anal length more than three times in total length; a small eye, diameter 2.0-2.2 in snout length; rictus ending at a vertical through posterior margin of pupil; ethmovomerine teeth patch small, with 58-74 blunt teeth arranged in seven to eight irregular rows; vomerine teeth patch small, with 18-28 granular teeth arranged in four to six irregular rows, distinctly separated by narrow spaces from the ethmovomerine and maxillary teeth; three supraorbital pores and one supra-temporal pore; and 159+ to 164 total vertebrae. Moreover, R. smithi differs significantly from four congeners, R. nitens, R. flavus, R. ectenurus and R. gracilior, with Kimura two-parameter (K2P) distances 14.6%-20.3%.

A new catfish of the genus Trichomycterus from the Rio Paraíba do Sul Basin, south-eastern Brazil, a supposedly migrating species (Siluriformes, Trichomycteridae)

A new species of the catfish genusTrichomycterusis described from the Rio Paraíba do Sul, south-eastern Brazil. This species exhibits some morphological character states that are unique amongst congeners, including a robust opercle and a long interopercle with numerous odontodes (50–60 opercular and 90–100 interopercular), a black bar on the basal portion of the caudal fin and a dark brown flank with a well delimited dorsal yellow stripe. It also exhibits some morphological traits that are uncommon amongst congeners, such as the presence of nine pectoral-fin rays. The presence of a shallow hyomandibular outgrowth and a ventrally expanded pre-opercular ventral flap suggests that this species is closely related toT. melanopygius,T. pradensisandT. tete. The new species also differs fromT. melanopygius,T. pradensisandT. teteby having an emarginate caudal fin and a single median supra-orbital pore S6. Anecdotal evidence suggests thatT. largoperculatusandT. pradensishave migratory habits, a condition not previously reported for eastern South American trichomycterines.

Coloconger maculatus sp. nov., a species of short-tail eel from eastern Taiwan (Anguilliformes: Colocongridae).

A new species of Coloconger is described from a large female collected off eastern Taiwan. It can be distinguished from congeners by having a large black blotch on rear portion of tail; posterior end of tail white; and combination of characters: head small 15.7% TL; 4 supratemporal pores, middle 2 in pair; 7 supraorbital pores, 2 pores over posterior nostril; 12 or 14 infraorbital pores; 14 preoperculomandibular pores; 226 dorsal-fin rays and 122 anal-fin rays; preanal vertebrae 77 and total vertebrae 145; rictus through a vertical of posterior margin of pupil; snout shorter than eye diameter; distance between origins of pectoral and dorsal fins 69.4% pectoral-fin length; and body brownish gray dorsally, light gray ventrally, and dorsal fin dark gray. Data and variations of Coloconger japonicus found in Taiwan are provided and discussed.

A new species of Congrid eel, Ariosoma melanospilos sp. nov., from Indian waters with taxonomic description of A. dolichopterum (Congridae: Bathymyrinae)

A new species of congrid eel, Ariosoma melanospilos sp. nov., is described from two specimens collected as bycatch landings of deep-sea trawlers at Colachel fish landing centre, off Kanyakumari, the southwest coast of India. The new species is distinguishable from all the known congeners in having two spots on both sides of the mid-dorsal temporal region (vs. absent in all congeners) and a wide interbranchial width of 25.0–30.3% head length. The new species resembles Ariosoma meeki (Jordan & Snyder, 1900) in possessing the unique character of two dark patches at the posterior margin of the eye but can be readily distinguished by the presence of a fifth supraorbital pore and three pores as ascending branch of the infraorbital canal behind the eye, three supratemporal pores (vs. absent in A. meeki) and four black spots on the temporal region. Genetic analysis reveals that the new species is closely related to Ariosoma anale (Poey, 1860) and A. meeki forming a clade with a genetic distance of 20.5% and 19.6%, respectively. We also report Ariosoma dolichopterum Karmovskaya, 2015, for the first time from Indian waters with meristic and morphological characters.

A new catfish species of Microcambeva Costa Bockmann 1994 (Siluriformes: Trichomycteridae) from a coastal basin in Rio de Janeiro State, southeastern Brazil.

Microcambeva bendego, a small psammophilous catfish species, is described from the rio Guapi-Macacu basin at Guanabara Bay in Rio de Janeiro State, an Atlantic Forest remnant. This coastal drainage has been explored by several naturalists and fish researchers since the 19th century. It is a drainage with remarkably high endemism and species richness, and some recently-described and threatened species. The new species is distinguished from all congeners by two distinctive characters: long finger-like projections in the branchial isthmus and a large opercular patch of odontodes with 19 odontodes. Due to the paucity of specimens (n=3) osteological features of the new species were accessed by CT-Scan images of the holotype. Microcambeva bendego shares putative synapomorphies with two congeners, M. ribeirae and M. filamentosa, such as the fusion of supraorbital pore s6, the absence of ossification in the anterior autopalatine cartilage, the presence of an elongated and wide posterior process of the autopalatine, and a concavity on the dorsal process of the opercle. Those characters suggest that M. bendego is more closely related to those two species from the rio Ribeira de Iguape basin than to other congeners. The biogeography and conservation status of M. bendego are also discussed.

Gross morphology of the cephalic sensory canal pores in Patagonian toothfish Dissostichus eleginoides Smitt, 1898 from southern Chile (Perciformes: Nototheniidae)

This study describes the cephalic sensory canal pores of the Patagonian toothfish's juvenile and adult specimens (Dissostichus eleginoides) from southern Chile. Specimens exhibited four supraorbital, eight infraorbital, and five mandibular pores, followed by six preoperculars, one coronal pore, one supratemporal pore, and four temporal pores. Juveniles exhibited circular pores in the mandibular, infraorbital, and preopercular region. The first two supraorbital pores are circular, the third is rectangular, and the fourth triangular. The coronal pore is circular with a bifurcation; the supratemporal pore is rectangular. In adults, the first mandibular canal pore is circular, and the last four are elongated. The preopercular canal pores are elongated. The two first supraorbital canal pores are circular, unlike the third and fourth, which are rectangular. The coronal pore is rectangular without bifurcation, and the supratemporal pore has a T-shape. The jaw of juveniles does not present all mandibular canal pores; in the infraorbital region, the first five pores extend as a thin canaliculus, while the adjacent pores appear as longer canaliculi in adults. The differences could be related to changes in spatial distribution during larval, juvenile, and adult stages. Adult cephalic sensory canal pores may have an important role in detecting vibratory waves allowing them to capture their prey and perceive potential predators. Our results provide information regarding the cephalic sensory canal pores of the Patagonian toothfish that may stimulate future studies of this species' mechanosensory system.

Sympatric sister species with divergent morphological features of psammophilic catfishes of the south-eastern Brazilian genus Microcambeva (Siluriformes: Trichomycteridae)

An undescribed species of Microcambeva, a genus of small psammophilic catfishes from the Atlantic Forest of south-eastern Brazil, was found together the congener Microcambeva ribeirae inhabiting the same sand stretch of a stream, in the Rio Ribeira do Iguape basin. The new species and its sympatric congener exhibit highly divergent morphological features, but a multigene phylogeny support them as sister taxa. The new species, M. filamentosa sp. nov., is readily distinguished from all other congeners by the presence of long barbels, long filamentous first pectoral-fin ray and a hypertrophied predorsal adipose fold. Microcambeva filamentosa and M. ribeirae share two unique apomorphic features: a single supraorbital pore s6 situated on the centre of the dorsal surface of the head and a deep concavity between the dorsal process of the opercle and the opercular odontode patch, conditions that are independently acquired in other psammophilic trichomycterids. A comparative context, involving other trichomycterid lineages exhibiting similar morphological adaptations, highly suggests that morphological differences between M. filamentosa and M. ribeirae are related to different strategies to exploit their habitat. In M. ribeirae, the short and thickened first pectoral-fin ray is interpreted as an adaptation to the fish posing propped on the substratum while visually detecting potential preys, what is reinforced by the unique possession in this taxon of a relatively large eye positioned on the top of the head. On the other hand, the relatively small eye and long barbels of M. filamentosa highly suggest the use of a predominantly chemosensory and tactile detection of food, indicating possible nocturnal habits.

Two new species of the genus Ophichthus from the western central Pacific Ocean, with a redescription of Ophichthus megalops Asano, 1987 (Anguilliformes: Ophichthidae).

Two new species similar to Ophichthus megalops Asano, 1987 with dark-tipped anal fins, are described on the basis of one specimen of each species. Ophichthus semilunatus sp. nov. from northeastern Taiwan is characterized by having 176 total vertebrae, three rows of teeth on the maxilla, one + three supraorbital pores, two preopercular pores, a brownish anterior-nostril tube, and a blotch on the anterior margin of anus. Ophichthus brevidorsalis sp. nov. from New Caledonia is characterized by having two preopercular pores, one + three supraorbital pores, smaller eyes 2.7 in head, a short head 9.5% of total length, a long tail 59.8% of total length, a slightly short snout 19.4% of head, and 43 predorsal vertebrae. A redescription of O. megalops is provided based on the holotype and 18 specimens newly collected from Taiwan. Selected characters of all nine Ophichthus with a dark-tipped anal fin are provided. In addition, partial COI sequences of five species is provided.

The cephalic lateral line system of the pelagic fish Normanichthys crockeri (Clark, 1937) (Pisces: Normanichthyidae) from southern Chile

The cephalic lateral line system of the Normanicthyidae family monotypic species, Normanichthys crockeri from Corral Bay, Chile was studied. N. crockeri is a small, schooling and pelagic fish from the southeast Pacific coast between Chimbote, Peru and Mocha Island, Chile. Normanichthys displays a cephalic latero sensorial system constituted by pores and canals. The pores are in six cephalic zones: five preopercular pores (pr.p), five mandibular pores (m.p), three supraorbital pores (so.p), eight infraorbital pores (io.p), three postorbital pores (po.p), three supratemporal pores (st.p) and only one coronary pore (c.p). The high number of pores distributed along the anterior, middle and posterior zones of the orbit stands out, making it a quite sensitive area. In the jaw, five elongated pores join those present in the preoperculum that, along with the rest of the cephalic pores in the supraorbital, supratemporal and postorbital regions make yet another area sensitive to the water flow. These pores are connected with eight narrow, continuous and simple canals: preopercular canal (PR), mandibular canal (MD), supraorbital canal (SO), infraorbital canal (IO), supratemporal canal (ST), otic canal (OT), post-otic canal (PO) and temporal canal (T). This type of canal is the most common pattern found among bony fishes and is designed to respond maximally to water flow velocity along the axis of the canal. These results will help understand part of the cephalic sensorial lateral line biology of this species, which has been barely considered in the ichthyological literature.

Mechanosensory system of the lateral line in the subantarctic Patagonian blenny Eleginops maclovinus

This study describes the cephalic and trunk lateral line systems in Patagonian blenny Eleginops maclovinus juveniles, providing morphological details for pores, canals and neuromasts. Eleginops maclovinus juveniles possess a complete laterodorsal lateral line that extends from the upper apex of the gill opening along the trunk as far as the caudal fin. The lateral line was ramified through pores and canals. The following pores were recorded: four supraorbital pores, with two along the eye border and two on the snout; seven infraorbital pores, with three on the lacrimal bone and four being infraorbital; five postorbital pores, with three along the preopercular border (upper preoperculum branch) and two on the bone curvature (inferior preoperculum branch); and four mandibular pores aligned along the jaw. Furthermore, five narrow-simple and interconnected canals were found (i.e. preopercular, mandibular, supraorbital and infraorbital canals). Histologically, the dorsal lateral line presented thin neuromasts (350 μm) with short hair cells. By contrast, the cranial region presented long, thick neuromasts. Infraorbital and mandibular neuromasts had a major axis length of 260 μm and respective average diameters of 200 and 185 μm. Sensory system variations would be due to a greater concentration of neuromasts in the cranial region, allowing for a greater perception of changes in water pressure. Scarce morphological information is available for the lateral sensory system in Eleginopsidae, particularly compared to Channichthyidae, Bovichthydae, Artedidraconidae and Bathydraconidae. Therefore, the presented results form a fundamental foundation of knowledge for the lateral-line system in juvenile E. maclovinus and provide a basis for future related research in this taxon as well as within the Notothenioidei suborder.

Notes on the congrid eel genus Parabathymyrus from the western Pacific Ocean, with the description of a new species (Pisces: Anguilliformes: Congridae).

The congrid eel genus Parabathymyrus from the western Pacific Ocean is reviewed and three species are recognized: Parabathymyrus macrophthalmus from Japan, Taiwan, Vietnam and Australia, P. brachyrhynchus from Taiwan, Vietnam, the Philippines, Vanuatu and Solomon Islands, and a new species, P. philippinensis sp. nov., is described based on two specimens collected from the Philippines. These three species can be distinguished from each other by the number of total vertebrae (128-137 in P. macrophthalmus, 162-173 in P. brachyrhynchus and 140-141 in P. philippinensis sp. nov.), preanal vertebrae (39-46, 49-58, and 42), preanal lateral-line pores (36-44, 46-54, and 40-42), total lateral-line pores (121-131, 159-169, and 140-141) and supraorbital pores (4, 4 and 3).

Bembidion (?Nipponobembidion) ruruy sp. n., a new brachypterous ground beetle (Coleoptera, Carabidae) from Kunashir Island, Kuriles, Russia.

A new species, Bembidion (?Nipponobembidion) ruruy sp. n., is described from the foot of Ruruy Volcano, Kunashir Island, Kuril Archipelago, Russia. It is only the second consubgener, being characterized by the reduced wings, the rounded elytral shoulders, and the backward position of the posterior supra-orbital pore. In this connection, the subgenus Nipponobembidion Habu & Baba, 1968 is rediagnosed and both of its species are keyed. It might have originated from Plataphodes Ganglbauer, 1891, possibly in relation to volcanic activities in the region.

Cephalic sensorial pores in galaxiid fishes from Chile (Osmeriformes: Galaxiidae)

The number and arrangement of the cephalic pores of the lateral line in Chilean fishes of the family Galaxiidae, were studied. The study showed that Brachygalaxias differs from Galaxias, in the absence of mandibular pores and in pore number reductions in the preopeopercular series. The most important variations were recorded in Galaxias globiceps and G. platei. The former species differed from the other species in the absence of a pore in the preopercular series, while in G. platei the supraorbital pore situated behind the eye was the main distinctive feature observed, in contrast to the upper position observed in the other species studied. A taxonomic key using cephalic sensory pores is proposed. These results indicate that the cephalic sensorial pores of the lateral line are a useful taxonomic character in the improvement of the diagnosis of galaxiid fishes -and in taxonomic and systematic studies among family Galaxiidae members. Keywords: Galaxiidae, morphology, lateral line, cephalic pores, taxonomy, Chile.

Trichomycterus payaya, new catfish (Siluriformes: Trichomycteridae) from headwaters of rio Itapicuru, Bahia, Brazil

Trichomycterus payaya, new species, is described from tributaries to the upper rio Itapicuru basin, northern Bahia State, Brazil. The new species is distinguished from congeners by having the head rounded anteriorly in dorsal view and slightly depressed in lateral view, supraorbital pores s6 paired, opening laterally on the supraorbital sensory branch, not emerging from an epiphyseal branch, lateral process of the urohyal distally sharp and with pointed tip, interopercular patch of odontodes longer than deep, with 21-26 odontodes, small number of pleural ribs (5-6 ribs), and dorsal fin in a posterior position. This is the first record of a Trichomycterus from the semiarid region of northeastern Brazil.

A New Species of Brachyhypopomus (Gymnotiformes, Hypopomidae) from Northeast Uruguay

A new species of Brachyhypopomus from north and northeast Uruguay is described. The new species is found in tributaries of the Uruguay River and southern Los Patos-Merín system. Brachyhypopomus bombilla can be distinguished from all other species of the genus by the following combination of characters: pigmentation pattern of body consisting of scattered dark brown pigmentation over a brown background, more dense on the dorsal half of the body, epidermal laterosensory canals not depigmented, head depth 61.8–76.4% of HL, caudal filament 6.5–16.6% of TL, anal-fin rays 155–190, fourth supraorbital pore dorsal and halfway between posterior nares and anterior margin of orbit, upper jaw slightly longer than lower jaw, mesocoracoid bone not ossified, maxilla anterodorsal process slender, all branchiostegal rays of equal size, none hook-like. Like many other species of the genus Brachyhypopomus, B. bombilla generates a pulse-type biphasic EOD, with a head-positive phase followed by a head-negative phase. The EOD duration of the new species was significantly lower than the EOD duration of the sympatric B. pinnicaudatus, whereas the EOD rate was significantly higher, thus suggesting that duration and frequency are conspicuous electrophysiological parameters that greatly aid in the description of electric fish species.

Two new species of the catfish genus Trichomycterus (Siluriformes: Trichomycteridae) from the rio Ribeira de Iguape Basin, southeastern Brazil

Two new species of the trichomycterid catfish genus Trichomycterus from the rio Ribeira de Iguape basin, southeastern Brazil, are described. Trichomycterus tupinamba differs from the other species of the Trichomycterinae in having the first pectoral-fin ray not prolonged as a filament, the caudal fin is truncate with attenuated edges, two paired supraorbital pores s6, eye oriented dorsally, a subterminal mouth, anal and urogenital openings mid-way between the pelvic-fin margin and anal-fin origin, a dark spot at the base of the nasal barbel, a longitudinal row of dark spots along the midline of the flank from the opercle to the caudal-fin base, a pectoral-girdle width of 13.1-17.7 % of standard length, and a caudal-peduncle depth of 8.7-10.3 % of standard length. Trichomycterus jacupiranga differs from all other species of the Trichomycterinae in having the first pectoral-fin ray prolonged as a short filament, one fused supraorbital pore s6, a pelvic fin that covers the anal and urogenital openings, anal and urogenital openings that are closer to the anal-fin origin than to the pelvic-fin base, a truncated caudal fin with attenuated edges, and the following morphometric characteristics: head length 20.7-22.4 % standard length, preanal length 57.1-70.9 % standard length, pectoral girdle width 17.4-20.6 % standard length, trunk length 33.6-37.5 % standard length, pectoral-fin length 16.8-22.7 % standard length, dorsal-fin base length 12.8-14.1 % standard length, anal-fin base length 8.4-10.8 % standard length, head width 90.6-104.6 % head length, snout length 40.0-46.9 % head length, mouth width 27.0-37.3 % head length, and eye diameter 10.4-16.5 % head length. Distribution, ecological data and diagnostic features are presented for both new species.

New Trichomycterus (Siluriformes: Trichomycteridae) from an Offshore Island of Colombia

Abstract Trichomycterus gorgona, the first insular trichomycterid species, is described from a small stream on Gorgona Island, located approximately 56 km west of the Pacific coast of Colombia. The new species differs from all congeners in the possession of a thick transverse skin flap between the pelvic fins. It is further distinguished by the following combination of characteristics: presence of eight or nine paired ribs (vs 12 or more), reduced pigmentation, and eyes reduced to small ovoid dots. Although epigean, the new species shares features commonly observed among troglomorphs, yet is distinguished from troglobitic Trichomycterinae in having the maxillary barbel extending to the anterior pectoral-fin margin, nasal barbels reaching the opercular odontodes, three supraorbital pores on the head (vs four pores), eight pectoral-fin rays (vs nine or 10) and the first ray prolonged as a filament, tip of adpressed pelvic-fin not reaching anal-fin origin (vs reaching origin of anal-fin), 39 or 40 vertebrae ...

Trichomycterus giganteus (Siluriformes: Loricarioidea: Trichomycteridae): a new catfish from the Rio Guandu basin, southeastern Brazil

Trichomycterus giganteus, new species, is described from the Rio Guandu basin, Serra do Mendanha, Rio de Janeiro city. Although being the biggest among species from southeastern Brazil and endemic to an older metropolitan area, it has gone unknown until the present, illustrating the poor knowledge of the taxonomy of this genus. It is distinguished from the remaining species of the genus by a combination of long nasal and maxillary barbels, a single median third supraorbital pore, long pectoral filament, nine pectoral-fin rays, high number of odontodes, relative position of the anal-fin origin, and a unique color pattern.

New species of the catfish genus Trichomycterus (Siluriformes, Trichomycteridae) from the headwaters of the rio S o Francisco basin, Brazil

Trichomycterus trefauti, new species, is described based on eight specimens from the rio S o Francisco basin, Minas Gerais, Brazil. The new species differs from all other trichomycterine species by the autapomorphic presence of an elliptical, vertically elongated, brown spot, at caudal-fin base, and the combination of homogeneously gray color pattern, first pectoral-fin ray prolonged as a filament, subterminal mouth, two supraorbital pores at interorbital space, caudal fin truncate with attenuated edges, pelvic fins covering anus and urogenital openings, interorbital space very wide (39.8 45.9 % head length), maxillary barbels very long (84.2 93.0 % head length), rictal barbels very long (67.6 74.3 % head length). Systematics, diagnostic features, and putative information on phylogenetic relationships of Trichomycterus species are discussed.

Dysomma opisthoproctus, a New Synaphobranchid Eel (Pisces: Synaphobranchidae) from the Northeastern Coast of Taiwan

A new species of synaphobranchid eel, Dysomma opisthoproctus, is described on the basis of a single specimen from the northeastern coast of Taiwan at depth about 200 m. It is characterized by a posteriorly positioned anus (1.5 times head length behind pectoral-fin base), well-developed cheek papillae, seven or eight compound dentary teeth, four compound vomerine teeth, four infraorbital pores, three supraorbital pores, seven preoperculomandibular pores, and 120 vertebrae (35 preanal vertebrae).