Yongeichthys Thomasi

📖 Overview

Endemic to brackish waters . Usually found in brackish waters of creeks close to river mouths, coastal lagoons , mangrove swamps , ponds and creeks . Rare reports of the species ascending rivers to freshwater, which it may tolerate for short periods . Maximum reported standard length 47 mm (=60 mm TL) .

🔬 Taxonomy

🐟 Physical Description

Dorsal spines (total): 7; Dorsal soft rays (total): 8 - 9; Anal spines: 1; Anal soft rays: 7 - 9. Diagnosis: mouth broad, lower jaw slightly prominent; outer row of caniniform teeth in lower jaw distinctly larger than inner rows; lateral teeth of this outer row particularly enlarged and backward-pointing; interorbital space narrow; small, cycloid, predorsal scales extending anteriorly beyond level of preoperculum, towards rear edge of orbit, with anterior margin of scaled area convex in dorsal view; 11-16 predorsal scales; small scales at bases of pectoral fins and slightly reduced scales at base of caudal fin; flanks covered with large, weakly ctenoid scales; 23-27 scales in longitudinal series (including about 2 scales on caudal fin base), 7-9 in rearward transverse series; 1st dorsal fin: VI, sometimes with spines prolonged; 2nd dorsal fin: I,8 (rarely 9); anal fin: I,7-9; pectoral fins: 15-17 rays; caudal fin rounded or subacuminate, with 17-18 segmented rays; tips of pelvic fins not reaching to anus . Coloration: Preserved specimens, as well as live individuals, can be identified by their characteristic pigmentation patterns; head with a black ‘chinstrap’ band slightly narrower than eye, running behind jaw, ventrally from lower margin of eye to isthmus on ventral part of head; blackish spot on upper part of pectoral-fin base, and another on flanks immediately dorsal to this; 3 black lines running anteriorly along head, each starting at pectoral spot: one band runs anteriorly along dorsal margin of operculum and preoperculum towards eye, where it extends anteroventrally along lower margin of eye until it meets black chinstrap band; 2nd band runs anteroventrally on operculum towards preoperculum or rear of suborbital region; 3rd band runs ventrally over operculum towards branchiostegal rays; body brownish, paler on belly; several irregular bars on back, sometimes extending onto flanks; faint band along midline, emphasized into about 5 regularly spaced spots on midline; dorsal and caudal fins dusky; distinct black spot at base of caudal fin; pelvic and pectoral fins dark; ventral region of pectoral-fin base with oval black spots, sometimes confluent and forming a crescentric band along lower fin margin; anal fin dark, especially near distal margin .: fusiform / normal.

🌀 Behaviour

Behavioural data for Yongeichthys Thomasi is currently being reviewed.

🦐 Diet

🥚 Reproduction

🌍 Habitat & Distribution

Marine; freshwater; brackish; demersal; amphidromous . Tropical; ? - 25°C

🌿 Ecology

📐 Morphometrics

🌡️ Water Parameters & Tolerance

🛡️ Conservation Assessment

📊 Population Risk & Fisheries

🌐 Names & Taxonomy

Scientific Synonyms

🐠 Related Species

🔍 Similar Species

🗺️ Global Occurrence Map

Occurrence records from the Global Biodiversity Information Facility (GBIF) - 20 records indexed .

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