Mandibular Pores Research Articles

A new species of the genus Enneapterygius (Perciformes: Tripterygiidae) from Japan and the Philippines, with a synopsis and synonymy of related species.

A new species of triplefin (Tripterygiidae), Enneapterygius olivaceus n. sp., is described on the basis of 28 type specimens (13.725.1 mm standard length: SL) from Japan (Ryukyu Islands) and the Philippines. The new species is characterized by having 1822 (20) notched lateral-line scales, 2 or 3 (2) scales below the 1st notched lateral-line scale, a single symphyseal mandibular-pore (mandibular pore formula 3 + 1 + 3), black pectoral fins in nuptial males, and no distinct line on the anal-fin membranes. In this study, Enneapterygius minutus (Gnther, 1877), previously regarded as a junior synonym of Enneapterygius philippinus (Peters, 1868), is considered a valid species, being redescribed based on 109 specimens, including the re-examined type specimens. Diagnostic characters and distributional records of the species closely related to E. olivaceus n. sp. are reviewed. Enneapterygius tusitalae Jordan & Seale, 1906, Enneapterygius pardochir Jordan & Seale, 1906 and Enneapterygius punctulatus Herre, 1935 are regarded here as junior synonyms of E. minutus; Tripterygium callionymi Weber, 1909 and Enneapterygius waigiensis Herre, 1935 are junior synonyms of Enneapterygius tutuilae Jordan & Seale, 1906; Enneapterygius cerasinus Jordan & Seale, 1906 is a junior synonym of Enneapterygius unimaculatus Fricke, 1994; Enneapterygius fuligicauda Fowler, 1946 is a senior synonym of Enneapterygius similis Fricke, 1997.

Turcinoemacheilus ekmekciae, a new dwarf loach from upper Tigris and Euphrates (Teleostei: Nemacheilidae).

Turcinoemacheilus ekmekciae, new species, from upper Euphrates and Tigris drainages is distinguished from other species of Turcinoemacheilus in Western Asia by having a dark stripe broader than the eye diameter along the lateral line, rarely possessing roundish blotches, 5-6 mandibular pores in mandibular canal, a comperatvely smaller head, a deeper body, and a greater pre-pelvic distance. Our specimens collected from the upper Great Zab, near the type locality of Turcinoemacheilus kosswigi, showed notable genetic divergence (a minimum K2P of 3.3%) from sequences reported as T. kosswigi in previous studies.Despite morphological similarities, this molecular difference suggests that the populations analysed in previous studies may represent a potential new species of Turcinoemacheilus, which we tentatively named as Turcinoemacheius cf. kosswigi. Molecular data also suggest that T. ekmekciae is characterized by a minimum K2P distance of 3.5% from Turcinoemacheilus minimus and T. cf. kosswigi. The three methods for species delimitation (assemble species by automatic partitioning [ASAP], Poisson tree processes [PTP], and multi-rate PTP [mPTP]) that were utilized for testing species assignments consistently identified our test group as a distinct species.

Opistognathusctenion (Perciformes, Opistognathidae): a new jawfish from southern Japan.

Opistognathusctenionsp. nov. (Perciformes: Opistognathidae) is described on the basis of three specimens (17.3-30.6 mm in standard length) collected from the Osumi and Ryukyu islands, southern Japan in depths of 35-57 m. Although most similar to Opistognathustriops, recently described from Tonga and Vanuatu, the new species differs in mandibular pore arrangement, dorsal- and caudal-fin coloration, fewer gill rakers, and lacks blotches or stripes on the snout, suborbital region and both jaws.

A New Species of Lycodapus from the Emperor Seamount Chain, Northwestern Pacific Ocean (Teleostei: Zoarcidae)

A new species, Lycodapus imperatorius, is described from the seamounts of the Emperor Ridge, North Pacific Ocean. The new species can be identified by its stout gill rakers, single interorbital pore, four preopercular and four mandibular pores, 95–99 vertebrae, numerous vomerine and palatine teeth, and COI mtDNA sequences. Although the new species is most similar to L. endemoscotus and L. antarcticus in morphology, the closest match to already published sequences was Lycodapus fierasfer, which is fairly different from the new species in terms of morphology. The incongruence between molecular and morphological inferences might be explained by the homoplastic nature of the morphological characteristics used for species delimitation in Lycodapus. The percent of genetic identity between the closest species of Lycodapus ranges from 95.4 to 98.6% in comparison with 99.5–100.0% between individuals of the same valid species. A key of the genus is amended to include the new species.

First record of the Triplefin fish, Helcogramma ellioti (Herre, 1944), from the Gulf of Oman, Iran (Blennioidei: Tripterygiidae: Tripterygiinae)

First record of the Triplefin fish (Blenniiformes: Tripterygiidae), Helcogramma ellioti , is reported here based on six specimens collected from Chabahar, northern Gulf of Oman in February 2019. Identification was confirmed based on a series of morphological characters including, a minute supraorbital tentacle, 3-5 symphyseal mandibular pores, a numerous number of scales in lateral line (36-37) and a low number of total lateral scale rows (38-39). Specimens were found in coral reef areas at depths of 1-15m of the Gulf of Oman in the Indo-Pacific region. Compared to the other members of Helcogramma , H. ellioti is regarded as a medium to large body size species (25.0-57.0mm SL). Although several species of triplefin fishes have been reported from the Persian Gulf, but, it is the first record from Tripterygiidae for the Iranian waters of the Gulf of Oman.

Cocotropus aurantius, a new velvetfish (Aploactinidae) from Japan

The new velvetfish Cocotropus aurantius is described on the basis of a single specimen (17.1 mm standard length) collected off Nagannu Island, Kerama Islands, Japan, at a depth of ca. 50 m. An individual of the new species has also been photographed off Izu Peninsula, Japan. The species is characterized by XII, 8 dorsal-fin rays, II, 6 anal-fin rays, 13 pectoral-fin rays, 7 segmented lower caudal-fin rays, 26 vertebrae, an interneural space between the 7th and 8th vertebrae lacking dorsal-fin spine proximal pterygiophores, the 1st–4th dorsal-fin spines situated anterior to the 3rd neural spine, 5 preopercular spines, vomerine teeth absent, the 2nd mandibular pore on each side fused, and the head, body and fins somewhat orange when fresh (preserved condition creamy-white), and with numerous small scattered brownish blotches and streaks.

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.

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.

Larvae of Huxelhydrus syntheticus Sharp, 1882 (Coleoptera: Dytiscidae: Bidessini).

The three larval instars of Huxelhydrus syntheticus Sharp, 1882, the only species of the New Zealand endemic genus Huxelhydrus Sharp, 1882, are described and illustrated including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of this species are characterized by the absence of the primary pore ABc, shared with all other known Bidessini larvae and therefore representing a potential synapomorphy of the tribe. Third instars of Huxelhydrus can be separated from those of all other known Bidessini genera by the following combination of characters: larger size, mandibular pore MNa located in a clearly distal position with respect to pore MNb, and presence of secondary setae on dorsal surface of protarsus, on posteroventral surface of all tarsi, and on urogomphus. First instars, on their part, can be distinguished by the presence of: an occipital suture, the primary pore PAk, a ventroapical spinula on antennomere 3, and an anterotransverse carina on meso- and metathorax.

Redescriptions of two western Pacific triplefins (Perciformes: Tripterygiidae), Enneapterygius fuscoventer and E. howensis

Two western Pacific triplefins, Enneapterygius fuscoventer Fricke 1997 and E. howensis Fricke 1997 (Perciformes: Tripterygiidae), are similar to each other in sharing 15–19 (usually 17) notched lateral-line scales and the mandibular pore formula 3–5 + 1 + 3–5 (usually 4 + 1 + 4), in addition to similar coloration, viz. body with four vertical bands, the first and second forked ventrally, dorsal-fin membrane semi-transparent, anal fin entirely blackish, and caudal fin blackish with a semi-transparent margin. These species have previously been known only from preserved specimens. Examination of additional specimens plus color photographs of males and females of both species when fresh, and comparisons with type specimens resulted in several features, including coloration and counts of second dorsal-fin spines, anal-fin soft rays, pored lateral-line scales and longitudinal scale rows, being regarded as new diagnostic characters. Enneapterygius fuscoventer and E. howensis have been newly recorded from southern Japan and coastal eastern Australia, respectively.

Larval description and chaetotaxic analysis of Dineutus sinuosipennis Laporte, 1840, with a key for the identification of larvae of the tribe Dineutini (Coleoptera, Gyrinidae).

The larvae of the Malagasy whirligig beetle Dineutus sinuosipennis Laporte, 1840, identified using DNA sequence data, are described and illustrated for the first time, including detailed morphometric and chaetotaxic analyses of selected structures and a description of larval habitat. Larvae of the genus Dineutus Macleay, 1825 are diagnosed, and a key to identify the genera of the tribe Dineutini is presented. Larvae of Dineutus exhibit the characters traditionally recognized as autapomorphies of the Gyrinidae: body less sclerotized, egg bursters located on the parietal, one additional sensorial plate on the third antennomere, cardo and lacinia well developed, prementum completely divided, abdominal tracheal gills, and four terminal hooks on the pygopod. They also share with larvae of the other Dineutini genera these putative synapomorphies: numerous minute pore-like additional structures on the ultimate maxillary and labial palpomeres, coxal primary seta CO12 inserted submedially, and trochanteral primary seta TR2 absent. Larvae of Dineutus can be distinguished from those of other known genera of Dineutini by the posterior margin of the lacinia not dentate, tracheal gills plumose, parietal seta PA5 inserted relatively far from setae PA7–9, mandibular pores MNb and MNc inserted relatively far from each other, and tarsal seta TA1 inserted submedially.

Gymnothorax visakhaensis sp. nov., a new species of elongate unpatterned moray eel (Muraenidae: Muraeninae) from the Indian Coast

An elongate, brown unpatterned moray eel, Gymnothorax visakhaensis sp. nov., is described based on seven specimens collected from the Visakhapatnam fishing harbour, Andhra Pradesh, India. The new species is differentiated from other elongate unpatterned moray eels in having the following combination of characters: anus at about mid-point of body, preanal length 1.9–2.1 in total length; snout blunt and short; dorsal-fin margin black, 6 mandibular pores; intermaxillary teeth biserial; maxillary teeth uniserial, sharp and depressible, pre-dorsal vertebrae 7, pre- anal vertebrae 70–74, total vertebrae 163–169.

Taxonomic review of dwarf species of Eumicrotremus (Actinopterygii: Cottoidei: Cyclopteridae) with descriptions of two new species from the western North Pacific

A taxonomic review of the dwarf species of the genus Eumicrotremus (Actinopterygii: Cottoidei: Cyclopteridae), previously recognized as belonging to Lethotremus, established the existence of three species, viz. Eumicrotremus awae (Jordan and Snyder, 1902), Eumicrotremus uenoi sp. nov., and Eumicrotremus jindoensis sp. nov., from the western North Pacific. Eumicrotremus awae, known from the Pacific coast of Honshu Is. (Chiba southward to Mie), is characterized by the absence of spiny tubercles or fleshy papillae on the body, the anterior three mandibular pores each with a barbel-like tube, interorbital and suborbital pores usually absent, the opercular flap rounded, many papillae present on the ventral disk and the caudal-fin relatively short, 21.0–30.5% of SL (standard length). Eumicrotremus uenoi, known from the western coast of Honshu Is. and the southern coast of Korean Peninsula, is characterized by the absence of spiny tubercles or fleshy papillae on the body (or weak if present), the anterior three mandibular pores each with a barbel-like tube, interorbital and suborbital pores usually present, the opercular flap rounded, the ventral disk with many papillae and the caudal-fin relatively short, 19.5–31.4% of SL. Eumicrotremus jindoensis, known from the southwestern coast of Korean Peninsula, and the coasts of Yellow Sea, is characterized by a smooth soft body, triangular opercular flap, absence of papillae on the ventral disk and a long caudal fin, 32.7–42.1% of SL. Sequence variations of the mictochondrial DNA cytochrome c oxidase subunit I (mtDNA COI) and the nuclear myh6 genes supported the validity of the three species.

A new species of the genus Diaphenchelys (Anguilliformes: Muraenidae) from Thailand

A new species of moray eel, Diaphenchelys dalmatian is described based on five specimens [289.8–503.0 mm total length (TL)] collected from the western coast of peninsular Thailand and the Gulf of Thailand. It can be easily distinguished from Diaphenchelys pelonates McCosker and Randall 2007, another species of the genus Diaphenchelys McCosker and Randall 2007, by its coloration (ground color white with brown dalmatian-like spots vs. brown with pale vermiculate pattern). The present new species also differs from D. pelonates in its longer tail (62.0–64.6% TL vs. 59.6–61.5%), fewer infraorbital pores along upper lip (three vs. four), fewer mandibular pores (five vs. six or seven), and fewer vertebral counts (preanal vertebrae 43–46 vs. 55–58; total 126–131 vs. 153–155). Diaphenchelys is closely similar to the genus Strophidon McClelland 1844 in the shape of neurocranium, the elongate body, low vertical fins, eye location, jaw shape, and presence of inner mandibular teeth. However, both differ in the vertebral counts (126–155 in Diaphenchelys vs. 164–208 in Strophidon) and coloration (prominent pattern vs. uniform).

A new species of elongate unpatterned moray eel of the genus Gymnothorax (Muraenidae: Muraeninae) from the Bay of Bengal.

An elongate, brown unpatterned moray eel, Gymnothorax indicus sp. nov., is described based on four specimens collected from the northern Bay of Bengal. The new species is differentiated from other elongate, unpatterned moray eels in having the following combination of characters: anus at about mid-point of body, preanal length 2.0 in total length; snout blunt and short; dorsal fin margin black, 5 mandibular pores; maxillary teeth uniserial, sharp and depressible, total vertebrae 194 (MVF: 9-79-194).

Larval Morphology ofYolaGozis, 1886 (Coleoptera: Dytiscidae: Bidessini) and Comparison with other Genera of the Tribe Bidessini

The second and third instars of Yola wraniki Wewalka, 2004 are described and illustrated for the first time, with detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment, and urogomphi. The mature larva of Yola Gozis, 1886 can be distinguished from those of the other known Bidessini genera by the following combination of morphometric and chaetotaxic characters: ratio length of metathoracic leg/head width greater than 2.85; ratio length of urogomphus/head width greater than 2.70; absence of a ventroapical spinula on third antennomere; secondary temporal spine-like setae on parietale; natatory setae on tibia; secondary posteroventral setae on tarsus and secondary setae on urogomphus; presence of pore PAk and secondary dorsal setae on protarsus; and mandibular pore MNa located in a clearly distal position with respect to pore MNb. A key for the identification of the third instars of the genera of Bidessini known in detail is provided.

Description of a new species of the genus Neenchelys (Anguilliformes: Ophichthidae, Myrophinae) from the eastern Indian Ocean, with comments on the availability of three congeners

A new worm eel, Neenchelys nudiceps, is described on the basis of a single large specimen (782 mm in total length) collected from the deep-sea bottom (844–856 m) off Sumatra, Indonesia, in the eastern Indian Ocean. The new species is distinguishable from its congeners by the following combination of characters: total vertebrae 221, mandibular pores 7, lateral-line pores anterior to pectoral-fin base 18, and upper and lateral surfaces of snout smooth without papillae. Additionally, it is indicated by a statistical analysis that the new species differs from the two similar species, Neenchelys daedalus and Neenchelys sp. “similis”, in morphometric characters. Availability of the three recently described congeners, N. diaphora, N. pelagica and N. similis is discussed, and it is judged that the three species names are unavailable.

A new species of the clingfish genus Kopua (Gobiesociformes: Gobiesocidae) from Japan

A new clingfish, Kopuavermiculata, is described on the basis of a single specimen collected from ca. 100 m depth off the Pacific coast of Honshu Island, Japan. The new species is distinguished from its congeners by having the following characters: dorsal fin rays 7; anal fin rays 6; segmented caudal fin rays 15; upper procurrent caudal rays associated with both neural spine of second preural centrum and epural; vertebrae 35; nasal pores 1; lacrymal pores 3; mandibular pores 3; predorsal length about 60 % of standard length; body whitish with distinct reddish-orange blotches on body; no reddish-orange stripes on cheek; belly whitish. A key to the species of Kopua is provided.

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.