Tetranchyroderma xenodactylum Hummon 2011

Adult being described Lt 246 µm (others 197–322); LPh 87 µm (others 79–128) to PhJIn at U35 (others to PhJIn at U40) (Fig. 16). Body short, robust, ventrally flattened, dorsally vaulted; head end rounded, without pestle organs, tentacles or lobes; neck a slight narrowing at the PhJIn, broadening along the mid-gut, before narrowing gently along the hind-gut and then quickly behind the anus to the caudal base; cirrata 4 per side (L 7–11 µm), dorsolateral at U22, U50, U72 and U96; caudal pedicles medium (L 13 µm), naked (without lobes), with a broad concave margin separating the two pedicles, incising medially to U92. Widths at mouth /mid-pharynx /PhJIn /mid-gut /caudal base, and locations along the length of the body are as follows: 41 /44 /39 /47 /22 µm at U06 /U19 /U34 /U66 /U93, respectively. A strange sub-cylindrical finger-like structure (L 7 µm) occurs at U34, being hollow but occluded at its outer end. Glands 9 per side (4 µm diameter to 6 × 9 µm) scattered in lateral columns at U24–U85. Cuticular armature: Epidermis armored with slightly curved pentancres (L 6, W 2.5 µm), much taller than wide, all 5 tines of the same length, ancres of much the same size over most of the body, but slightly smaller fore and aft; ancres cover dorsal and lateral surfaces in some 46 rows of 14–15 ancres each, extending onto the middle of the oral hood and onto the caudal base. Adhesive tubes: TbA 4 per side, 1 medially (L 4 µm) projecting forward and 3 laterally (L 6–8 µm), projecting obliquely to the side, all inserting directly on the postoral body surface at U09–U10. TbVL 11 per side, 1 (L 4 µm) along the fore half of the pharynx at U14, just behind the TbA, 7 (L 7–12 µm) along the intestine at U39–U75, and 3 (L 7–12 µm) at and behind the anus at U88–U92; TbV 3 per side (L 7, 11, 7 µm) in a transverse row at U80; TbLper seand TbD are absent; TbP 3 per side on the caudal pedicles, forming the fused ‘two fingers and a thumb’ typical of the many members of the family, (L terminal tubes 4–5 µm, L tube on the inner margin 9 µm), supplemented by the last of the dorsal cirrata, with 2 additional tubes (L 7–8 µm) in the space between the peduncles. Ciliation: Short sensory cilia surround the oral opening (L 4 µm), with a number of also on the oral hood: 6 (L 14–17 µm) projecting directly or obliquely forward and 13–15 (L 7–14 µm) trailing to the rear; other cilia (L 10–18 µm) occur regularly along the lateral and dorsolateral body surfaces, numbering 12–13 each. Ventral locomotor ciliature forms a single field of transverse rows from TbA to behind the anus, lying between the TbVL columns; individual cilia are 5–6 µm in length. Digestive tract: Mouth subterminal, as broad as the fore end of the body (34 µm width); oral hood extends from U00 to U07; buccal cavity lightly cuticularized; pharynx of medium breadth throughout, with inconspicuous basal pores; intestine narrows gradually front to rear; anus is ventral at U88. Reproductive tract: Hermaphroditic, testis on right side as seen from above (left side as seen from below); vas deferens appears to open in front of the anus; developing ovum (up to 29 × 16 µm), appearing somewhat shrivled, occurs above the hindgut; caudal organ spherical (7 µm diameter); frontal organ oblong (20 × 14 µm) and hyaline, without active sperm, partly embedded in the rear of the ovum.

Geographical distribution: RED SEA: EGYPT {Marsa Bareika W, ^Nabq [sdom] (28°05'N, 34°35'E) [2-videos], Sharm el-Sheikh, Wadi ’Araba [video]}.