Tenerognathia visus Tanaka 2005
Creators: name: Ota, Yuzo
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Gnathiidae
Tenerognathia
Tenerognathia visus

description: Tenerognathia visus Tanaka, 2005
(Figs 1–5)
Tenerognathia visus Tanaka, 2005: 565 [type locality: Cape Maeda, Okinawa-jima Island, Japan, 26°26´N, 127°46´E].— Ota et al. 2007: 1266.— Kensley et al. 2009: 32.—Ota. 2012: 79, 91, 93.
Material examined. NSMT-Cr26752, 6 adult males, 5 adult females, and 5 third-stage praniza larvae, Yonara-suido channel (24°33´91.1´´N, 123°94´80.6´´E), 0–10 depths, off Kohama-jima Is., Ryukyu Islands, Japan during night on 3–4 November 2012.
Description. As morphologies of adult male were well described in original description, this study omitted most part of description and shows other details of morphology.
Adult male (Fig. 1). Total length of body 1.3–2.1 mm (mean ± SD, 1.8 ± 0.4 mm; n = 6). Pigmentation of live specimens entirely reddish. Cephalosome (Fig. 1A, B) elliptical with three pairs of setae and narrow ridge on frontal border; mediofrontal process present. Compound eyes occupies whole of the cephalosome and mesial margins in contact (Fig. 1B). Mandibles short and not well-developed with one mandibular seta (Fig. 1B). Pleotelson (Fig. 1D, E) with acute apex; with three or two pairs of setae.
Adult female (Figs 2, 3). Body length 2.0– 2.2 mm (mean ± SD, 2.1 ± 0.1 mm; n = 5). Pigmentation of live specimens entirely whitish. Cephalosome (Fig. 2A) with one pair of setae. Frontal border straight. Pereonite 1 not fused to cephalosome, reaching lateral margin. Pereonite 2 and 3 convex. Pereonite 3 wider than pereonite 2 with seta on lateral margin. Pereonite 4–6 swollen with two sutures. Lateral shields of pereopods 3–5 visible dorsally. Pereonite 7 reduced, overlapping pleopod 1. Pleonite 1–5 (Fig. 2A, B) each with pair of setae on lateral margin. Epimera prominent on pleonites 1–5. Pleotelson (Fig. 2B, C) triangular with scales on dorsal surface. Two pairs of setae on dorsal surface and distal margin, respectively.
Antennula (Fig. 2D) composed of three basal and four flagellar articles. One or two setae on distal margins of 3 basal articles. One aesthetasc each on flagellar articles 3 and 4.
Antenna (Fig. 2E) composed of four basal and seven flagellar articles. One feather-like bristles on peduncular article 3.
Maxilliped (Fig. 3A) consists of coxa with attached oostegite, basis and four-articled palp. Tips of endite reaching half-length of palp article 1. Two simple setae on inner margin of palp article 1. Three, five, and three plumose setae on inner margins of palp articles 2, 3, and 4, respectively. Five setae on distal margin of palp article 4.
Pylopod (Fig. 3B) composed of three articles; article 1 curved and fringed with setae on inner margin; article 2 rectangular with one seta, and article 3 minute. Pylopodal oostegite semi-oval.
Pereopod 2 (Fig. 3C) almost same structure as in male adult of T. visus; basis rectangular with one simple seta distally; ischium triangular with five simple setae; merus rectangular with five simple setae distally; carpus with two simple setae and one denticulated compound seta; propodus rectangular, bearing two denticulate compound setae on inner-mid and inner-distal margins; dactylus terminal unguis robust and ventral claws.
Pereopod 3 similar to pereopod 2. Pereopods 4–6 narrower and longer than those of pereopods 2 and 3.
Pleopods (Fig. 2I) with reduced setae; two or three setae on endopods and from one to five setae on exopods. Exopods of all pleopods shorter than endopods.
Uropodal rami (Fig. 2C) extend beyond apex of pleotelson; endopod and exopod fringed with nine simple setae, respectively; four penicillate setae on endopod.
Third-stage praniza larva (Fig. 4). Body length 1.9–2.4 mm (2.2 ± 0.2, n = 5). Pigmentation of live specimens entirely reddish. Cephalosome (Fig. 4A, B) semicircular, length approximately 0.6 times width. Clypeus length approximately 0.4 cephalosome length; concave anterior margin. Eyes approximately 0.6 cephalosome length and inner margin not reaching basis of antennae. Pereonite 1 (Fig. 4B) axially thin, length less than basal width of cephalosome. Lateral shields of pereonites 3–6 visible in dorsal view, and elliptical. Pair of setae on dorsal surface of pereonite 2 and 3. Pereonite 7 reduced, overlapping pleopod 1.
Pleonite 1–5 (Fig. 4A) lengths subequal, with two pairs of setae on lateral margins. Epimera prominent on pleonite 5. Pleotelson (Fig. 4C) with three pairs of short setae, almost same shape as that of male adults.
Antennula (Fig. 4D) composed with three basal and four flagellar articles. Two penicillate setae on basal article 2. One aesthetasc on each flagellar articles 2, 3, and 4.
Antenna (Fig. 4E) composed with four basal and seven flagellar articles; one penicillate seta on distal margin of basal article 3.
Mandible (Fig. 4F) with five teeth. Paragnath (Fig. 4G) slightly curve. Maxillula (Fig. 5H) with six teeth. Maxilliped (Fig. 4I) composed with two basal articles and two palps. Basal article 1 with elongated endite and fringed with fine setae on external margin. Basal article 2 with coupling hook on inner margin. Palp 1 with long seta on inner margin, bifurcate; external part terminates with five setae and one spine, internal part with one seta. Palp 2 with two teeth.
Pereopod 1 (Fig. 4J) with distinct spine on distal margin of ischium. Carpus triangular with one distal seta; propodus with one seta on distal margin; unguis well curved.
Pereopod 2 (Fig. 4K) stouter than that of female adult; basis with two penicillate setae; merus and carpus with one long denticulate compound seta on distal margin; propodus with two denticulate compound setae on inner-mid and inner-distal margins; dactylus terminal unguis robust and ventral claws.
Pereopod 3 with almost same morphology. Pereopods 4–6 longer than pereopods 2 and 3. Pleopod 2 (Fig. 4L) with fan-shaped exopod and oval-shaped endopod. Both rami fringed with setae. Nine plumose setae on exopod. Nine plumose setae on endopod. Uropodal rami (Fig. 4C) not extend apex of pleotelson. Exopod with four simple setae and four plumose setae and endopod with two simple setae and five plumose setae. One penicillate seta on endopod.
description: Published as part of Ota, Yuzo, 2019, Description of female adult and praniza larva of Tenerognathia visus Tanaka, 2005 (Crustacea; Isopoda; Gnathiidae) with notes on mating behavior, pp. 561-570 in Zootaxa 4711 (3) on pages 562-567, DOI: 10.11646/zootaxa.4711.3.7, http://zenodo.org/record/3586685