Simognathus adriaticus Viets, 1940

Simognathus adriaticus Viets, 1940

Figures 5A–I View FIGURE 5 , 6D, E View FIGURE 6 ; Table 3 View TABLE 3

[ Simognathus adriaticus Viets, 1940: 95–97 ; Figs. 143–149]

Material examined. Protonymph (FDHAL-24/112), undissected and slide mounted, St.1 ( Ayvalik , Balikesir), fine sand with P. oceanica, 5 m, 39.342060, 26.710070, 30 Sept. 2019 GoogleMaps . Two deutonymphs (FDHAL-24/110, FDHAL-24/111) undissected and slide mounted, St. 5 ( Kundu , Antalya), fine sand, 2 m, 36.849361, 30.839000, 22 June 2019 GoogleMaps .

Morphology and notes. Deutonymphs. Dorsal plates uniformly foveate ( Fig. 5A View FIGURE 5 ).AD with a transverse hyaline lens at anterior end. Posterior to hyaline lens, area of AD foveate. Dorsal setae small. AD anteriorly truncated, posteriorly rounded., bearing ds-1. OC triangular, narrowing posteriorly. Pair of ds-2 to ds-4 striated in integument. Pair of ds-5 and ds-6 on PD. All ventral plates separated and foveated ( Fig. 5B View FIGURE 5 ) AE with three pairs of setae and a pair of large epimeral vesicles. Posterior part of AE truncate. PE with a dorsal and three ventral setae. Anterior part of GA truncate. GA with two pairs of gac and one pair of pgs, no sgs ( Fig. 5 View FIGURE 5 B') Gnathosomal base foveate. Palps three segmented ( Fig. 5C View FIGURE 5 ). Surface of all telofemora foveated. Leg chaetotaxy as follows (bipectinated setae between parentheses) ( Figs. 5D–G View FIGURE 5 ); Leg I: 1, 2, 1, 4, 5, 6; Leg II: 1, 1, 2, 4, 5(2), 6; Leg III: 1, 1, 2, 3, 5(2), 6; Leg IV: 1, 1, 1, 3, 5(2), 6.

Protonymph. All plates are smaller than deutonymphs ( Figs 5H, I View FIGURE 5 ). Number and arrangement of dorsal idiosomatic setae same as in deutonymph. Epimeral vesicles clearly seen ( Fig. 5I View FIGURE 5 ). Leg chaetotaxy as follows (bipectinated setae between parentheses); Leg I: 1, 2, 1, 4, 5, 6; Leg II: 1, 1, 2, 4, 5(2), 6; Leg III: 1, 1, 2, 3, 5(2), 6; Leg IV: 0, 1+2 (basifemur+telofemur), 2, 5(2), 5.

Remarks. The genus Simognathus Trouessart, 1889 comprises 44 named species of which only two species, S. adriaticus Viets, 1940 and S. leiomerus Trouessart, 1894 , are known from the Mediterranean Sea. S. adriaticus was described by Viets (1940) from Croatia (Rovigno) among various macroalgae and other substrates. Later, the species was reported from sublittoral sand habitat from Antalya (in Stamouli et al. 2017). The present author also reported this species on the north of Aegean Sea (Çanakkale, Bozcaada) ( Durucan 2021). The species belongs to minutus group. This species group may be recognised by having large, triangular or rounded OC and generally with cornea ( Bartsch 1994) and additionally S. adriaticus may recognised by: (1) body uniformly with lightbrownish pigmented, (2) median plate punctate in AE, (3) OC large, triangular, narrowing posteriorly in adults and deutonymphs, but the corners more rounded in protonymphs, (4) knob present on second palpal segment in adults but not observed in deutonymphs and protonmyphs.