Macrodasys imbricatus Hummon 2011

Adult being described Lt 544 µm (others Lt 541–625); LPh 234 µm (others LPh 200–205) to PhJIn at U43 (others PhJIn at U32–U38) (Fig. 6). Body medium in length as an adult, ventrally flattened, dorsally vaulted; head stepped, narrowing toward the mouth, bearing pestle organs in the step at U03; trunk broadest in the pharyngeal region, narrowing gradually to the long caudum. Widths at pestle organs /pharynx /PhJIn /anus /caudum, and locations along the length of the body are as follows: 40 /60 /56 /31 /22–6 µm at U03 /U26 /U43 /U80 /U84–U98, respectively. Glands not conspicuous. Adhesive tubes: TbA 5–6 per side (L 7 µm), in transverse rows, which insert directly on the postoral body surface at U02 and project forward; TbL/TbV are unusual and complex, with 35 per side, from U28 to U95, with the first 4 being lateral and the others rotating ventrally, while the last TbL 3 along the caudal base are duplicated by 3 of the last 4 TbV; TbL 7, symmetrically and evenly placed and of similar size, with 2 along the fore and 2 along the rear pharynx, 2 along the rear intestine, and 1 more behind the anal aperture; TbV 28 per side, symmetrically placed but uneven in spacing and size (L 6–18 µm), with 1 along the rear pharynx, and the remainder in the intestinal region, 2 of which occur behind the anus, with numerous cases of side-by-side tubes; TbP 11 per side (L 10–12 µm) symmetrically surround the elongate caudum. Ciliation: Sensory cilia (L 5–12 µm) occur around and on either side of the mouth; head lacks a ciliary corona, other sensory cilia arise in four columns on either side of the body: lower lateral (L 12–15 µm), upper lateral (L 7–9 µm), dorsolateral (L 15–26 µm) and dorsal (L 15–26 µm), with about 19, 34, 27 and 16 per column. Ventral locomotor cilia form a single field that lies between the TbL/V series back to the tip of the tail, with bare spots surrounding the ventral reproductive and anal openings. Digestive tract: Mouth terminal, of medium-broad width (16 µm diameter); inner mouth rim bears a series of longitudinal ridges, extending half the depth of the buccal cavity; buccal cavity is mug-shaped, expanding slightly from oral opening to base and, is lightlycuticularized; pharyngeal musculature can be seen, with para-basal pharyngeal pores at U36; intestine is broadest in front, narrowing slowly to the rear; anus is ventral at U80. Reproductive tract: Hermaphroditic; testes begin just before the PhJIn and vasa deferentia extend back to the rear of the frontal organ, though their termini were not seen; ova probably develop from rear to front, but only one small ovum was seen (22 × 18 µm in size); a tubular frontal organ occurs behind the ovum, having a refractile cuticular nozzle and circular muscles in the front three-fifths, as well as containing motile sperm, and cellular material in the accessory chamber, covering the rear two-fifths; long caudal organ appears to have circular muscles over the rear half that lie atop longitudinal muscles, which occur over the entire length of the organ, except for its rearmost glandular sac that lies at an obtuse angle to the rest.

Geographical distribution: RED SEA: EGYPT: {16 km S of Ein Sukhna [video], Marsa Bareika W, Sharm el-Arab Inside [video], Hammam Pharoan [dom] [videos], ^Main Beach Ras Mohamed NP (27°44'N, 34°12'E) [video], Ras Nasrani, Tareef el-Reeh [video], Tip Ras Mohamed NP [cdom]}; ISRAEL: {Coral Beach M2 [video], M3 [3-videos], M4 [video], Coral Beach N)}