Gyge wimi, Boyko & Williams, 2025

Gyge wimi sp. nov.

( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 )

Type material: Persian Gulf: Iran: Holotype, ovigerous female (8.1 mm) ( SMF 62932 About SMF ) GoogleMaps and mature male allotype (3.4 mm) ( SMF 62933 About SMF ), infesting left branchial chamber of male Upogebia carinicauda (Stimpson, 1860) (11.4 mm CL), silt/sand with mussels, 2 km east of desalinization plant (26° 56.252’ N 55° 47.831’ E), Qeshem Island , coll. R. Naderloo & M. Türkay, 15 Jan 2008 (SMF 38659). GoogleMaps

Type host: Upogebia carinicauda (Stimpson, 1860) .

Description: Holotype ovigerous female (SMF 62932): General body shape ( Fig. 3A, B View FIGURE 3 ) elongate ovate, body segments separate, body asymmetrical, slight right distortion (<5°); total length 8.1 mm, maximal width (across pereomere 3) 5.6 mm. Head subquadrate, approximately 1.4 times wider than long (length 1.6 mm, width 2.2 mm), nearly straight anteriorly, rounded posteriorly, not fused with first pereomere, dorsal surface smooth, lateral margins rounded ( Fig. 3A View FIGURE 3 ). Frontal lamina absent, eyes absent. Pereon broadest across pereomere 3, all pereomeres dorsally, ventrally and laterally distinct ( Fig. 3A View FIGURE 3 ). Pereomere 1 curved forward around head, reaching its distolateral corners, anterior margin of pereomeres 2 and 3 curved forward, 4–7 curved backward ( Fig. 3A View FIGURE 3 ). All pereomeres without tergal projections; coxal plates present on pereomeres 1–4, elongate, not overlapping, dorsolateral bosses present on pereomeres 1–4 ( Fig. 3A View FIGURE 3 ).

Antennule of three articles ( Fig. 3C View FIGURE 3 ); basal article quadrate with few short setae distolaterally; article 2 subcylindrical with few short setae distally and distolaterally; distal article subcylindrical, smaller than article 2, with tuft of short setae distally.

Antenna of five (left) or six (right) articles ( Fig. 3C View FIGURE 3 ); basal article globose, article 2 ovate, article 3 subcylindrical with few short setae distally, article 4 elongate with few short setae distally, article 5 minute, much smaller than 4, with tuft of short setae distally.

Barbula ( Fig. 3D View FIGURE 3 ) formed by two digitate lateral lamellae, middle region with additional digitation on each side, center with single smooth short projection.

Maxilliped ( Fig. 3E View FIGURE 3 ) without palp, few very fine short setae on weakly extended distomedian region, basal segment subtriangular with short plectron, distal segment subquadrate, slight indentation and very small setae in position where palp would be if present.

Pereopods ( Fig. 3H, I View FIGURE 3 ) subequal in size and structure; dactylus short, smooth, with few short setae on dorsal margin; propodus cylindrical with few short setae on distodorsal surface and semicircular ridged region distoventrally with small socket for dactylar insertion; carpus subcylindrical with distoventral area of scales and distal tuft of setae; merus ovate with scales along ventral region, ischium elongate, smooth; basis irregularly shaped, scales and short setae along proximoventral region.

Marsupium with five pairs of smooth oostegites not fully enclosing brood pouch ( Fig. 3B View FIGURE 3 ). Oostegite 1 ( Fig. 3F, G View FIGURE 3 ) with subcircular anterior article, smaller than posterior article, internal with fewer than 10 stubby projections, posterior article rounded with elongate distolateral projection, distally rounded.

Pleon with five pleomeres ( Fig. 3A, J View FIGURE 3 ) dorsally and laterally separated, dorsal and ventral surfaces smooth. Five pairs of lateral plates, small, smooth, not dorsally visible. Five pairs of smooth, weakly biramous pleopods, 1–4 subequal in size, 5 much smaller, endopods and exopods subequal ( Fig. 3J View FIGURE 3 ); uropods uniramous, similar in size to pleopod 5 ( Fig. 3J View FIGURE 3 ).

Allotype male ( SMF 62933 About SMF ): Body ( Fig. 4A, B View FIGURE 4 ) with elongate outline, unpigmented, distinctly segmented dorsally, ventrally and laterally, symmetrical, total length 3.4 mm, maximal width at sixth pereomere, 1.2 mm ( Fig. 4A View FIGURE 4 ). Head ovate, fused with first pereomere, approximately 3 times as wide as long; anterolateral borders rounded; two small, irregular dark eyes near posterior margin of head ( Fig. 4A View FIGURE 4 ).

Antennule and antenna of 3 and 5 articles, respectively ( Fig. 4C View FIGURE 4 ); antenna approximately 2 times longer than antennule; antennule with few seta near distal margin of first article and tuft of setae at distal end of second and third articles; antennae with few setae on distal margin of second article and tuft of setae on distal margins of articles 3–5; antennae extending beyond distal margin of head ( Fig. 4A, B View FIGURE 4 ).

Maxillipeds absent.

Pereomeres separated, directed and tapered laterally ( Fig. 4A View FIGURE 4 ); midventral tubercles present on pereomeres 1–7, minute on 1 and 2, larger on 3–7 ( Fig. 4B View FIGURE 4 ).

Pereopods subequal in size but first three pairs with larger propodi and stouter meri ( Fig. 4B View FIGURE 4 ); scales present on ventral border of propodus of pereopods 1–7, and on ventral surface of carpus and merus of pereopods 4–7; all pereopods with raised ridge at distoventral margin of propodus for insertion of dactylus tip ( Fig. 4C, E View FIGURE 4 ).

Pleon ( Fig. 4A, B View FIGURE 4 ) of four segments plus pleotelson; shorter than pereon; pleomeres progressively narrower posteriorly, distinctly separated, lateral margins with rounded tips; pleomeres 1 and 2 extended laterally, 3 and 4 extended posterolaterally; midventral tubercles present on pleomeres 1–4; pleopods absent; pleotelson deformed (asymmetrical) but apparently with lateral lobes and produced terminal margin ( Fig. 4D View FIGURE 4 ); uropods absent.

Distribution: Known only from the type locality.

Etymology: We are pleased to name this species in honor of Wim Decock, Science Officer in the Data Centre of Flanders Marine Institute/Vlaams Instituut Voor De Zee (VLIZ) on the occasion of his retirement. Wim has been an amazing resource and of great help with making sure that the World Register of Marine Species (WoRMS) runs smoothly and is kept up to date and fully functional.

Remarks: SMF 38659 contains seven males, eight females, and two juvenile specimens of U. carinicauda . Gyge wimi sp. nov. is most similar to the Asian G. ovalis ( Shiino, 1939) in the general body shape of the mature female and the partly open marsupium but differs from this species in having smooth pleopods and uropods ( G. ovalis with tuberculate pleopods and uropods), the uropods visible in dorsal view ( G. ovalis with uropods not visible in dorsal view) and the posterior lobe of the first oostegite straight ( G. ovalis with posterior lobe recurved). The male of G. wimi sp. nov. has the lateral margins of the pleomeres and pereomeres tapered ( G. ovalis with rounded lateral margins) and has large midventral tubercles on the posterior five pereomeres and all pleomeres ( G. ovalis with large midventral tubercles on posterior four segments and none on pleomeres). The asymmetrical pleotelson of the male appears to be a developmental abnormality; new collections are needed to determine the true morphology of this structure which may be more extended with symmetrical lateral lobes (as in G. branchialis ) or small and rounded (as in G. ovalis ). A key to females of all species of Gyge is provided below.