Ichthyological Research最新文献

Extant ‘fishes’ belong to jawless, cartilaginous, actinopterygian, or sarcopterygian fish lineages. They comprise a non-monophyletic group of vertebrates from which tetrapods are excluded, and they are therefore paraphyletic. Recent advances in whole-genome sequencing have shed light on phylogenetic relationships, divergence times among major fish lineages, and the molecular basis of phenotypic diversity. This review encompasses the diversity of extant fishes and explores the variation in genomic organization and its evolutionary origins. This review begins with evaluating available genomic sequence resources with a focus on literally complete (‘telomere-to-telomere’) sequencing. Next, it discusses among-lineage variations in genomic contents, considering karyotype reports, genome sizes, and whole-genome duplication events. Additionally, we investigate three families of protein-coding genes, visual opsins, aquaporins (Aqps), and Hox genes, as they offer insights into morphological and physiological differences among major fish lineages. Overall, our technical basis of analyzing fish genomes and the knowledge of genomic organization provide valuable insights into our vertebrate-wide understanding of how molecular mechanisms specifying variable phenotypes are encoded in genomic sequence information.

This study is a taxonomic review of the ponyfish genus Equulites Fowler 1904 (Leiognathidae), which is diagnosed by the following combination of characters: downward projecting mouth; small teeth forming a narrow band on jaws; a dark blotch on neither nape nor spinous dorsal fin; clearing of the guanine-lined gas bladder extending to the full length of the bladder, not restricted posteriorly, a triangular or trapezoid translucent patch ventrolaterally on body in males; dark vermiculation, broad oblong ring markings and/or short oblique lines on the dorsolateral body. Ten species are herein recognized: three species of the Equulites elongatus species group [Equulites aethopos Suzuki and Kimura 2017—restricted to the southern Red Sea; Equulites elongatus (Günther 1874)—Myanmar, Indonesia and northern Australia; Equulites popei (Whitley 1932)—the Red Sea, Mozambique, Oman, Gulf of Thailand, Malaysia, Philippines and Japan, Mediterranean by Lessepian migration]; Equulites berbis (Valenciennes in Cuvier and Valenciennes 1835) (neotype designated herein)—widely distributed in the Indo-West Pacific, from the Red Sea and eastern coast of Africa to Indonesia, north to Japan, Mediterranean by Lessepian migration; Equulites laterofenestra (Sparks and Chakrabarty 2007)—Malaysia, Philippines, Indonesia and northern Australia; Equulites leuciscus (Günther 1860)—Seychelles, Myanmar, Thailand, Malaysia, Philippines, Indonesia, Papua New Guinea, northern Australia, Taiwan, and Japan; Equulites macrolepis sp. nov. Suzuki, Osmany and Kimura—Pakistan and western coast of Thailand; Equulites oblongus (Valenciennes in Cuvier and Valenciennes 1835) (lectotype designated herein)—India, Sri Lanka, Thailand, Malaysia, Philippines, Indonesia and Timor Island, north to Japan; Equulites rivulatus (Temminck and Schlegel 1845)—China, Taiwan, Korea and Japan; Equulites ryukyuensis sp. nov. Kimura and Suzuki—restricted to Okinawa, Japan. Diagnoses and descriptions (except for the Equulites elongatus species group) are provided for each species. The taxonomical status of Equula lineolata Valenciennes in Cuvier and Valenciennes 1835 is discussed.

The validity of Scolopsis regina Whitley 1937, described from a single specimen from Australia and long treated as a junior synonym of Scolopsis monogramma (Cuvier in Cuvier and Valenciennes 1830), is confirmed in this study. The two species share the following features: 45–48 lateral-line scales; 9–11 total gill rakers on first gill arch; no anteriorly projecting suborbital spine; scaled dorsal area of head reaching anteriorly to between anterior margin of eye and posterior nostril; bony ridge of opercle and lower limb of preopercle scaled; scaled lateral area of head extending to just behind eye; and two longitudinal blue bands connecting anterior margins of eyes when fresh. However, S. regina is distinguished from S. monogramma by having 18–20 (modally 19) scale rows below the lateral line [vs. 17–20 (18) in S. monogramma], 6 or 7 (7) preopercular scale rows below eye [5 or 6 (6)], two distinct brown bands across dorsum of snout after preservation (lower band indistinct), a distinct suborbital blue band from lower margin of eye to upper-jaw lip when fresh (blue band indistinct or absent) and the blue band becoming a distinct brown band after preservation (band disappearing), caudal-fin base dark blue when fresh (yellow), a blue longitudinal band on upper caudal-fin lobe (absent), relatively long upper and lower caudal-fin lobes (relatively short), and a relatively wide marginal blue band posteriorly on caudal fin (relatively narrow). Scolopsis regina is distributed off northern Australia, whereas S. monogramma occurs in East and Southeast Asian waters.

A detailed morphological investigation, including osteological anatomy based on micro-CT scans, of two poorly known monotypic genera and species of gobiesocids, Lissonanchus lusherae Smith 1966 and Briggsia hastingsi Craig and Randall 2009, revealed that no generic-level differences existed between the two species. Briggsia Craig and Randall 2009, therefore, is a junior synonym of Lissonanchus Smith 1966. Lissonanchus is rediagnosed, having the following characters: 30 or 31 vertebrae; cephalic lateral-line canal pores poorly developed, including 2 nasal, 2 lacrimal and 1 postorbital canal pores; posterodorsal portion of anguloarticular strongly expanded laterally with bifurcated process; gill membranes on each side united ventrally, attached to the isthmus; 4th gill arch without filaments; double type adhesive disc; flattened papillae on disc region A continuous across center; flattened papillae on disc region D arranged along disc edge and continuous with papillae on disc region A; center of anterior disc (= middle area between disc regions A and D) lacking papillae; small fleshy pad on lower part of pectoral-fin base; anterior part of dorsal-fin base lacking a swollen fleshy appearance; general fresh coloration, including brownish-green body, dark brown strip extending from snout tip to posteroventral part of head through eye, and whitish part on lateroventral surface of head (bordered by dark brown strip). In particular, the anguloarticular feature of Lissonanchus is likely unique within the Gobiesocidae and is regarded as a putative autapomorphy for the genus. In contrast, the two species could be distinguished from each other by species-level differences, including counts of pectoral-fin rays, number of teeth on pharyngobranchial 3, jaw lengths, and streak patterns on the body. Accordingly, Lissonanchus is now considered to include two valid species: L. lusherae (type species) and Lissonanchus hastingsi, new combination. Although Lissonanchus was previously included in the subfamily Diademichthyinae, the genus does not share any diagnostic features of that subfamily, and the subfamilial assignment of the genus remains equivocal, like other Indo-Pacific genera considered as incertae sedis within the Gobiesocidae (e.g., Aspasmogaster Waite 1907, Conidens Briggs 1955, and Creocele Briggs 1955).