Short Lower Jaw Research Articles

The barracudina genera Lestidium and Lestrolepis of Taiwan, with descriptions of two new species (Aulopiformes: Paralepididae).

Two genera of barracudinas with luminescent duct in abdominal cavity, Lestrolepis and Lestidium, collected from around Taiwan are studied. Two species in each genus are recognized in Taiwan, including one new species in each genus. New diagnostic characters are used to distinguish these species. Lestrolepis nigroventralis sp. nov. is similar to Lestrolepis intermedia and can be distinguished by having 32-35 prehaemal vertebrae; dorsal-fin origin slightly in front of midline of distance between origins of pelvic and anal fins, distance between origins of dorsal and pelvic fin 9.8-11.7% SL; and pelvic-fin origin at or slightly behind midline of body, prepelvic length 50.6-52.6% SL. Lestidium orientale sp. nov. is similar to Lestidium atlanticum and can be distinguished by having prehaemal vertebrae 37-40; caudal vertebrae 41-44; a relatively short and deep head, reflected by a shorter snout (9.7-10.4% SL), shorter upper jaw (8.6-10.1% SL), shorter lower jaw (11.9-13.7% SL) and a deeper head (31.2-33.9% HL). Data of Lestrolepis japonicus and Lestidium prolixium collected from Taiwan, as well as two Atlantic congeners, are provided. DNA barcoding is conducted to support the recognition of these new species.

A new species of sardine, Sardinellapacifica from the Philippines (Teleostei, Clupeiformes, Clupeidae).

A new sardine, Sardinellapacificasp. n., is described on the basis of 21 specimens collected from the Philippines. The new species closely resembles Sardinellafimbriata (Valenciennes, 1847), both species having lateral scales with centrally discontinuous striae, a dark spot on the dorsal-fin origin, more than 70 lower gill rakers on the first gill arch, the pelvic fin with eight rays, and 17 or 18 prepelvic and 12 or 13 postpelvic scutes. However, the new species is distinguished from the latter by lower counts of lateral scales, pseudobranchial filaments, and postpelvic scutes (38–41, 14–19 and 12–13, respectively vs. 44–46, 19–22 and 13–14), and a shorter lower jaw (10.4–11.6% of standard length vs. 11.1–12.2%). Sardinellapacificasp. n. is known only from the Philippines, whereas S.fimbriata is restricted to the Indian Ocean, although previously considered to be an Indo-West Pacific species, distributed from India to the Philippines.

Three new species of the cutthroat eel genus Dysomma, with comments on the variation of D. taiwanense (Anguilliformes: Synaphobranchidae).

Three new species of eels of the genus Dysomma are described from the western North Pacific Ocean off Taiwan. Dysomma formosa sp. nov., described from 34 specimens, differs from the congeners in having single row of 11-14 large compound teeth followed by 3-10 smaller teeth on lower jaw, 17-33 lateral-line pores, and 128-133 total vertebrae. Dysomma brachygnathos sp. nov., described from two specimens, differs from the congeners in the lack of a pectoral fin, having an anterior position of anus (preanal length 17.8-ca. 18.6% SL), 23-32 lateral line pores, a short lower jaw, and 131+‒136 total vertebrae. Dysomma robinsorum sp. nov., described from four specimens, differs from the congeners in having an anterior position of anus; preanal length 15.5-16.9% SL, no intermaxillary teeth; multiple rows of teeth on upper jaw; four compound teeth on vomer; teeth on lower jaw multiserial, those on inner row slightly enlarged, and 122-124 total vertebrae. Components of the variation of Dysomma taiwanense originally described from Taiwan are provided based on an additional 52 recently identified specimens.

АНОМАЛАД П’ЄРА-РОБЕНА В КЛІНІЧНІЙ ПРАКТИЦІ ПЕДІАТРА

Уроджена вада щелепно-лицевої ділянки з вираженим недорозвитком нижньої щелепи як наслідок зменшення ротової порожнини і западання язика перешкоджає змиканню піднебінних пластинок з формуванням щілини м’якого піднебіння, що часто поєднується з множинними іншими аномаліями. В основі даного синдрому лежить аномалія росту і розвитку зародка, що характеризується порушенням розвитку початкового зародкового стану (внаслідок вади першої зябрової дуги). Язик розміщений сильно назад, досягаючи синусів носа, між глотково-піднебінними дужками, які орієнтовані сильно вниз. Розвиток цих аномалій зумовлений деякими інфекціями матері під час вагітності або нейрогенетичними порушеннями, наявністю механічної компресії всередині матки, а також вони можуть виникати внаслідок сімейної спадковості (на їх користь вказують вади обличчя в деяких членів однієї чи іншої родини). Основні діагностичні критерії: мікрогнатія (мала, коротка нижня щелепа) та (або) ретрогнатія (запала нижня щелепа). У хворого характерний профіль, подібний на пташиний рот, «пташине обличчя», рот до кінця не закривається, тому його називають «ротом акули»; глосоптоз (недорозвиток та западання язика) – невелика і втягнута нижня щелепа не може тримати язика в нормальному положенні, так що він впадає назад у гіпофаринкс, здавлюючи надгортанник, який відіграє роль клапана та перешкоджає проникненню повітря, одночасно порушується і ковтання. Іноді відмічається макроглосія, язик прирощений до м’яких тканин дна ротової порожнини; щілина м’якого піднебіння або «стрілчате піднебіння» (одно- чи двобічне незрощення). Усі ці аномалії спричиняють респіраторний дистрес-синдром, порушення дихання, неспокій, диспное з брадипное, постійний ціаноз, які особливо виражені при положенні дитини на спині, асфіксію при годуванні дитини, утруднення чи неможливість ковтання, блювання, з часом – атрепсію і порушення окостеніння. Ізольовані випадки аномаладу П’єра Робена завжди спорадичні. Аномалад є складовою частиною синдрому множинних уроджених вад розвитку, успадкування визначається залежно від типу успадкування основного синдрому. Актуальними при даному синдромі є виключення всіх несприятливих факторів у допологовий період розвитку дитини, пренатальна діагностика, проведення медико-генетичного консультування з метою попередження народження дитини зі спадковим захворюванням.

Taxonomic status of a population of Gymoncypris waddelli Regan, 1905(Cypriniformes: Schizothoracinae) distributed in Pengqu River, Tibet, China.

Gymnocypris waddelli, a highland cold-water fish, is distributed among rivers and lakes of the southern Qinghai-Tibet Plateau. Although previously described as G. waddelli, specimens from the Pengqu River are morphologically distinguishable from those from Lake Yamzhog Yumco, which is the type locality of G. waddelli. We investigated morphological variations of G. waddelli specimens from Pengqu River and Lake Yamzhog Yumco using not only traditional morphological methods but also newly-developed geometric morphometric analysis; furthermore, mitochondrial Cytochrome b (Cyt b) gene analysis was employed to explore the phylogenetic position of the Pengqu River population. Our morphological analyses suggested that G. waddelli from the Pengqu River had an obtuse snout, nearly straight oral fissure, shorter lower jaw than upper jaw, broad mouth and sparse inside gill rakers of the first arch relative to the Lake Yamzhog Yumco population. The strongly supported monophyly of Pengqu population according to mitochondrial datasets was obtained, indicating genetic differences between Pengqu River and Lake Yamzhog Yumco populations. Given their substantial genetic and morphological divergence, specimens from Pengqu River warrant recognition as a distinct species, here described and named Gymnocypris pengquensis.

Tributyltin exposure results in craniofacial cartilage defects in rockfish (Sebastiscus marmoratus) embryos

Tributyltin (TBT) is a ubiquitous marine environmental contaminant, which has been known to cause axial skeletal deformities in fish embryos. However, the effects of TBT on the craniofacial cartilage development of fishes remain unclear. The present study was designed to investigate the effects of waterborne TBT at environmental levels (0, 0.1, 1, and 10 ng L−1 as Sn) on craniofacial cartilage development in embryos of the rockfish (Sebastiscus marmoratus). Our study showed that TBT exposure induced craniofacial skeletal deformities, such as reduction of the craniofacial skeleton elements and a shorter lower jaw. The expressions of retinoic acid receptor α, sonic hedgehog, and proliferating cell nuclear antigen were depressed and the expressions of vitamin D receptor were increased in the rockfish embryos after TBT exposure. In addition, the activities of Ca2+-ATPase were inhibited after TBT exposure. These results suggested that TBT might perturb the proliferation and differentiation of chondrocytes, and disturb calcium homeostasis, thus disorganizing craniofacial skeletal development.

Cichlasoma zarskei, a new cichlid fish from northern Brazil (Teleostei: Labroidei: Cichlidae)

Cichlasoma zarskei sp.n. is herein described from the rio Maranhão basin, northern Brazil. The new species differs from all its congeners, except C. orientale, by having a conspicuous posterior band of the longitudinal stripe and dorsal, anal and caudal fins faintly dotted. It is also distinguished from its congeners by the precense of the following character states: trisserial predorsal squamation, four anal-fin spines, reduction of the squamation between dorsal and anal-fins rays, forâmen between infraorbital plate 3+4 and plate 5 smaller, deeper entopterygoid, premaxilla with teeth on its entire dentigerous surface, caudal-fin base spot not ocellated, fewer pleural ribs, more scales on E1 series, shorter last dorsal-fin spine, shorter last anal-fin spine, longer snout, wider head and shorter lower jaw. A new diagnosis for C. orientale, without overlapping character states, is herein presented.

Epitheliogenesis imperfecta in a flock of Awassi sheep in Iraq

Congenital absence of the skin in Awassi sheep is described. At birth, the affected lambs lacked all skin layers over many body parts. Furthermore, the affected lambs exhibited deformed teeth and a shorter lower jaw. It is thought that an autosomal recessive gene is involved in bringing about this condition.

Trophic specialization in Arctic charr Salvelinus alpinus (Pisces; Salmonidae): morphological divergence and ontogenetic niche shifts

Abstract Lake Thingvallavatn supports four trophic morphs of Arctic charr, Salvelinus alpinus (L.); two of the morphs are benthic (small and large benthivorous charr) one exploits pelagic waters (planktivorous charr) and the fourth is found in both habitats (piscivorous charr). The morphological variation among these morphs was analysed by use of principal component analysis and canonical discriminant analysis. The benthic morphs have a short lower jaw and long pectoral fins. The benthic fish also have fewer gillrakers than the other morphs. Small and large benthivorous charrs attain sexual maturity from 2 and 6 years of age, and at fork lengths from 7 and 22 cm, respectively. Small benthivorous charr retain their juvenile parr marks as adults, have beige ventral colours, and are frequently melanized under the lower jaw. Planktivorous and piscivorous charr attain sexual maturity from 4 and 6 years of age, from fork lengths of 15 and 23 cm, respectively. This phenotypic polymorphism is associated with habitat utilization and diet of the fish, and has probably arisen within the lake system through diversification and niche specialization. The pelagic morphs apparently stem from a single population, and are possibly diversified through conditional niche shifts which affect ontogeny. Juveniles reaching a body length of 23 cm may change from zooplankton to fish feeding. Asymptotic length increases thereby from 20.5 cm in planktivorous charr to 30.2 cm in piscivorous charr. The benthic morphs appear to represent separate populations, although both feed chiefly on the gastropod Lymnaea peregra . Their co-existence seems to be facilitated by size dependent constraints on habitat use. The small morph (asymptotic length 13.3 cm) exploit the interstitial crevices in the lava block substratum, whereas the large morph (asymptotic length 55.4 cm) live epibenthically.

Trophic specialization in Arctic charr Salvelinus alpinus (Pisces; Salmonidae): morphological divergence and ontogenetic niche shifts

Lake Thingvallavatn supports four trophic morphs of Arctic charr, Salvelinus alpinus (L.); two of the morphs are benthic (small and large benthivorous charr) one exploits pelagic waters (planktivorous charr) and the fourth is found in both habitats (piscivorous charr). The morphological variation among these morphs was analysed by use of principal component analysis and canonical discriminant analysis. The benthic morphs have a short lower jaw and long pectoral fins. The benthic fish also have fewer gillrakers than the other morphs. Small and large benthivorous charrs attain sexual maturity from 2 and 6 years of age, and at fork lengths from 7 and 22 cm, respectively. Small benthivorous charr retain their juvenile parr marks as adults, have beige ventral colours, and are frequently melanized under the lower jaw. Planktivorous and piscivorous charr attain sexual maturity from 4 and 6 years of age, from fork lengths of 15 and 23 cm, respectively. This phenotypic polymorphism is associated with habitat utilization and diet of the fish, and has probably arisen within the lake system through diversification and niche specialization. The pelagic morphs apparently stem from a single population, and are possibly diversified through conditional niche shifts which affect ontogeny. Juveniles reaching a body length of 23 cm may change from zooplankton to fish feeding. Asymptotic length increases thereby from 20.5 cm in planktivorous charr to 30.2 cm in piscivorous charr. The benthic morphs appear to represent separate populations, although both feed chiefly on the gastropod Lymnaea peregra. Their co-existence seems to be facilitated by size dependent constraints on habitat use. The small morph (asymptotic length 13.3 cm) exploit the interstitial crevices in the lava block substratum, whereas the large morph (asymptotic length 55.4 cm) live epibenthically.

A new long-headed dipnoan (Osteichthyes) from the middle Devonian of Iowa, USA

ABSTRACT The new genus and species Iowadipterus halli is described from the Middle Devonian of Iowa, U.S.A. Iowadipterus is a long-headed but not long-snouted dipnoan with many distinct features: cheek bones 8 and 9 enlarged, bone 8 bordering bones Y1 and Y2 so that only bones Y2 and Z lie dorsal to the operculum; cheek pit line passing from bone 8 directly to bone 9; elongation of B- and C-bones without differentiation of D- or E-bones; narrow submandibular combined with broad gulars; and scales with tubercles with a shallow depression on the overlapped part of scale. Iowadipterus and possibly Holodipterus are long-headed dipnoans with a short lower jaw, in contrast to long-headed forms with a long snout (Griphognathus, Soederberghia, Rhynchodipterus, and Fleurantia with elongated rami, and Rhinodipterus with an elongated symphysis). The broad cheek offers a wide space for the adductor muscles and indicates a powerful bite.