Lophogaster manilae Băcescu, 1985

Lophogaster manilae Băcescu, 1985 View in CoL

( Fig. 4 View Fig )

Lophogaster sp. ? sensu W. M. Tattersall, 1951: 20, fig. 1d.

Lophogaster sp. A sensu O. S. Tattersall, 1960: 542, fig. 6.

Lophogaster sp. sensu Murano, 1970: 3, fig. 2.

Lophogaster sp. sensu Wang and Liu, 1997: 195; Liu and Wang, 2000: 63: fig. 3.

Lophogaster manilae Băcescu, 1985: 360 View in CoL , fig. 2a–n; Casanova, 1993: 37, fig. 2; — 1996: 140, fig. 6e–h; Yolanda et al., 2023b, 418.

Material examined. West Pacific. Central

Japan: Suruga Bay ; 1 juv. (cl 1.2 mm), KT-69-6, St. 363-5, 34°50.0′N, 138°37.9′E – 34°49.4′N 138°37.7′E, 380– 300 m, ORI net, horizontal tow, 10 May 1969, coll. M. Murano (NSMT-Cr 32882) GoogleMaps ; — 1 male (cl 4.8 mm), damaged slightly, KT-69-6, St. 389-6, 80–0 m, IKMT, 12 May 1969, coll. M. Murano (NSMT-Cr 32883) : —

Suruga Bay , off Toi; 1 female (cl 5.5 mm) damaged slightly, KT-76-16, St. T2 , 300– 294 m, 2 m Beam Trawl , 23 Sept 1976, coll. M. Murano (NSMT-Cr 32884). East China Sea . 5 males (cl

4.0– 5.8 mm), 7 females (cl 4.2–5.6 mm), 51 juvs (cl 2.7–3.0 mm), KH-74-3, St. B 11-1, 31°15.7′N 128°20.6′E – 31°17.5′N 128°22.1′E, 369– 364 m, 3 m Beam Trawl, 5 Aug 1974, coll. M. Murano (NSMT-Cr 32885). Sulu Sea, 1 female (cl 4.8 mm), KH-72-1, St. 12, 08°19.0′N 118°09.1′E – 08°18.7′N 118°08.5′E, 500– 495 m, inner net of 3 m Beam Trawl , 27 May 1972, coll. M. Murano (NSMT-Cr 32886) GoogleMaps .

Diagnosis. Body integument somewhat calcified.

Carapace ( Fig. 4a–d View Fig ) with several to numerous fine tubercles or processes on anterior part, but smooth on posterior part; rostral plate well developed, covering entire basal 2 segments of antennular peduncle and part of cornea of eye; lateral margin ending in marked disto-lateral process, directed slightly outwards, or sometimes slightly curving inwards, posterior margin evenly concave; male rostral process ( Fig. 4c View Fig ) short, as long as antero-lateral processes, while female rostral process ( Fig. 4a, b View Fig ) much longer than in male, its upturned apex reaching as far as end of antennular lamina; post-ocular process/spine absent; posterior median part rounded or weakly ridged; postero-lateral part with short process (alar spine), directed slightly downwards.

Abdomen ( Fig. 4e View Fig ) with ventral median spine or tooth on first 5 somites decreasing its height posteriorly; sixth somite 1.0–1.3 times as long as fifth, with moderately long postero-lateral process; pleura on anterior 5 somites angulated or toothed at postero-ventral part, and generally becoming sharper posteriorly.

Telson ( Fig. 4e, f View Fig ) 1.8–2.2 times as long as sixth abdominal somite, with obtusely rounded ridge in basal part of dorsal surface; armed laterally with 2 or 3 setal-spines in addition to possible ordinary 2 distal pairs, penultimate one moderately long, reaching mid-length of terminal one, terminal plate well noticeable, bearing 4 small spinules and pair of plumose setae.

Exopod of uropod ( Fig. 4e, f View Fig ) slightly shorter than endopod, outer margin smooth and naked, ending distally in process.

Antennular lamina ( Fig. 4 g View Fig ) with anteriorly produced rounded lobe and small process in antero-median part and single long seta arising from concaved part between 2 projections.

Antennal scale ( Fig. 4h View Fig ) bell-shaped or nearly rounded, 1.3–1.6 times as long as broad, outer margin weakly convex, armed on anterior 2/5 with 3 or 4 teeth, becoming stouter anteriorly, terminal tooth strongly curving inwards.

Remarks. This species shows marked sexual dimorphisms in the rostral plate and rostral process as females have a much longer rostral plate as well as longer rostral process than those of males (see also Casanova, 1993). In addition, the postero-lateral tooth on the carapace (= alar spine) shows variations at some extent, and one female in this study showed an angulation in the identical part instead of an ordinal toothed process.

Distribution. This species has been collected in the western Pacific, from Japan to New Caledonia and the Wallis and Futuna Islands.