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Sunday, February 7th, 2021
| Time | Event | ||||
| 10:23a | [Ichthyology • 2021] Review of the Hagfishes (Myxinidae) from the Galapagos Islands, with Descriptions of Four New Species and Their Phylogenetic Relationships
Abstract Hagfishes are an ancient group of benthic marine craniates that are found in deep or cold waters around the world. Among the 83 valid species, four are described from the Galapagos Islands: Eptatretus bobwisneri, E. grouseri, E. mccoskeri and Rubicundus lakeside. During a recent expedition to the archipelago, six species of hagfishes were collected, including four undescribed species of the genera Eptatretus (Eptatretus goslinei sp. nov.) and Myxine (Myxine greggi sp. nov., M. martinii sp. nov. and M. phantasma sp. nov.). In this paper, we provide a review of the eight species of hagfishes from the Galapagos Islands, including new diagnoses and an identification key for all species. Myxine phantasma is remarkable in that it is the only species of Myxine known to completely lack melanin-based pigments. Our species delineations were based on both morphological and molecular analyses. A phylogenetic hypothesis based on molecular data suggests that Galapagos hagfishes arose from multiple independent colonisations of the islands from as many as five different ancestral lineages. The large number of endemic hagfishes in the geologically young Galapagos Islands suggests that there is much global hagfish diversity yet to be discovered. Ecuador, Eptatretus, Myxine, Myxiniformes, systematics  Eptatretus goslinei sp. nov.  Myxine greggi sp. nov.  Myxine martinii sp. nov.,  Myxine phantasma sp. nov., M. M. Mincarone, D. Plachetzki, C. L. McCord, T. M. Winegard, B. Fernholm, C. J. Gonzalez, and D. S. Fudge. 2021. Review of the Hagfishes (Myxinidae) from the Galapagos Islands, with Descriptions of Four New Species and Their Phylogenetic Relationships. Zoological Journal of the Linnean Society. zlaa178. DOI: 10.1093/zoolinnean/zlaa178 | ||||
| 10:36a | [Ichthyology • 2021] Bagarius vegrandis | ปลาแค้วัว • A New Species of Sisorid Catfish from Indochina (Siluriformes: Sisoridae), with Notes on the Identity of Bagarius bagarius
Abstract Bagarius vegrandis, new species, is described from the Chao Phraya and Mekong river drainages. It differs from congeners in having a small maximum body size (to 220 mm SL vs. 520–1400 mm SL) and the adipose-fin origin markedly posterior to (vs. at vertical through or very slightly posterior to) the anal-fin origin. It further differs from congeners in having the following unique combination of characters: ovoid unculiferous plaques on dorsal surface of head, lateral margin of frontal not significantly deflected dorsally, eye diameter 11–15% HL, interorbital distance 23–28% HL, head width 18.3–22.3% SL, head depth 11.1–14.1% SL, filamentous extensions to first pectoral-fin element reaching to anus, dorsal spine width 10.6–13.9 times in its length, body depth at anus 8.7–12.0% SL, neural spines of the 4–6 vertebrae immediately anterior to adipose fin distally flattened but not forming series of prominent bumps along dorsal midline, length of adipose-fin base 10.8–13.0% SL, caudal-peduncle length 19.0–22.4% SL, caudal-peduncle depth 3.2–4.2% SL, 19–20 preanal vertebrae, and 39–40 total vertebrae. Bagarius bagarius (Hamilton, 1822) is demonstrated to be a species restricted to the Indian subcontinent (with Bagrus yarrelli Sykes, 1839, Pimelodus platespogon Valenciennes, in Jacquemont, 1839 and Pimelodus carnaticus Jerdon, 1849 as junior subjective synonyms) and Bagarius lica Volz, 1903 resurrected from synonymy with B. yarrelli as a valid species from Southeast Asia. Keywords: Pisces, taxonomy, morphology, species delimitation, Southeast Asia
Heok Hee Ng and Maurice Kottelat. 2021. Description of Bagarius vegrandis, A New Species of Sisorid Catfish from Indochina (Actinopterygii: Siluriformes), with Notes on the Identity of Bagarius bagarius. Zootaxa. 4926(1); 134–146. DOI: 10.11646/zootaxa.4926.1.9 ปลาแค้ (หรือแข้) ประเทศไทยมี 4 ชนิด 1. แค้วัว Bagarius vegrandis พบในลุ่มเจ้าพระยาและโขง 2. แค้หัวแบน Bagarius suchus พบในเจ้าพระยาและโขง 3. แค้ยักษ์ Bagarius lica ทุกลุ่มน้ำยกเว้นสาละวิน 4. แค้ยักษ์สาละวิน Bagarius sp. Salween พบเฉพาะในสาละวิน |
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