Tetraclita ehsani Shahdadi, Chan & Sari 2011

Parietes conical, white to pink or white with pink ribs (Fig. 1A), radii and alae narrow, sheathstriate, parallel to base and about ? height of wall, sheath white to dirty white, or pink. Parietes composed of 3-4 rows of honey comb parietal tubes (Fig. 1B). Scutum and tergum white (Fig. 1B, C, D). Scutum narrow, 1.5 times higher than wide, lower half of occludent margin with >10 oblique teeth, articular ridge sinuous, adductor ridge extremely developed, angular and extending to basal margin, adductor muscle pit shallow, seven distinct rostral and four to six lateral depressor crests (Fig. 1B, C, D), external surface smooth with faint horizontal striations (Fig. 1). Tergum long and narrow (length more than twice as width) with ten definite depressor crests, scutal margin slightly concave, spur long and narrow, external spur surface with a medial furrow, basi-scutal angle sharp and about 117.8°, upper carinal margin convex and basal margin slightly concave or straight (Fig. 1B, C, D). Carinal-basal angle (angle between the carinal and basal margin) is ~103° (Fig. 1C). Mandibular palps elongate, setae on superior margin only, simple type setae at tip and serrulate setae at the middle region of the superior margin (Figs 2A, 3A, B, C). Labrum notched, notch shallow, four erect large teeth on each side of the cutting edge (Figs 2B, 3E–H). Mandible with five teeth excluding the inferior angle, first tooth separated from the remaining teeth, second and fourth teeth bidentate, third teeth tridentated fifth tooth small and located close to the fourth tooth, lower margin with >10 setae, height of setae similar to height of the fifth tooth, inferior angle sharp, with two large setae on tip, mandible surface with blade shaped serrulate type setae (Figs 2C, 3G–L). Maxillule notched, with two large and four small simple setae above notch, 11 setae in median cluster and 10 small and slender simple setae on the cutting margin below notch (Figs 2D, 3M–O). Maxilla bi-lobed, serrulate type setae at both lobes (Figs 2E, 3P–S). Cirrus I anterior ramus antenniform, twice as long (27 segments) as posterior ramus (10 segments) (Figs 4, 5A), both rami with a feathery serrulate type setae (3–4 rows dense setules in each seta) and a serrulate type setae (very sparse setule along the seta) (Fig. 5B–D). Cirrus II with shorter rami, anterior and posterior ramus similar in length (each with 10 segments), with serrate and simple setae (Fig. 5E–G). Cirrus III with longer anterior ramus (anterior and posterior ramus 13 and nine segments respectively; Fig. 4). Both rami bear bidentate serrate setae, feathery serrulate setae and blade shaped serrulate setae, protopod bears pappose setae with long feather seta (Fig. 5H–M). Cirrus IV–VI ctenopods, cirrus IV with 17 segments for both anterior and posterior rami, cirrus V, anterior ramus 21 segments, posterior ramus 19 segments, cirrus VI, anterior ramus 18 segments, posterior ramus 22 segments. Intermediate segment of anterior ramus of cirrus VI bears 3 pairs of long serrulate setae and 3 pairs of short setae (Fig. 4E, F).

At present, only known from the Iranian coast in the Gulf of Oman and absent from the Persian Gulf (see Shahdadi 2007).