Acanthodasys caribbeanensis, Hochberg, Rick & Atherton, Sarah, 2010

Hochberg, Rick & Atherton, Sarah, 2010, Acanthodasys caribbeanensis sp. n., a new species of Thaumastodermatidae (Gastrotricha, Macrodasyida) from Belize and Panama, ZooKeys 61, pp. 1-10 : 2-3

Acanthodasys caribbeanensis sp. n. Figs 13

Type locality.

Station CBC10.19, Carrie Bow Cay Reef, coarse sand patches on ridge, 15 m depth, 16°48.127N, 88°04.607W. Sediments collected by Cheryl Thacker on January 23, 2010.

Holotype.

Adult specimen, reproductively mature, 625 µm long, resin preparation: specimen in dorsoventral orientation. USNM #1145897

Other localities.

Station BRS2010-104, Wild Cane Rock, Bocas del Toro, Panama, 14 m depth, medium coarse sand plain, 9°21.016N, 82°10.335W. Sediment collected by Daniel Gouge on June 8, 2010.

Paratypes.

Cat. No. USNM 1145898, Adult specimen, minimum 425 µm long (curled), resin preparation: specimen on side. Cat. No. USNM 1145899, Adult specimen, minimum 450 µm long (curled), resin preparation: specimen in dorsoventral orientation.

Material examined.

Ten specimens. Three prepared for archival.

Diagnosis.

Acanthodasys with an adult body length from 375 µm to 625 µm long. Maximum body width at mouth/PIJ/midpoint of body is 30/62/100 µm. Pharynx to 238 µm long. Cuticle of spineless and spined scales. Spineless scales of various shape. Spined scales bear uniancres to 50 µm long, distributed as one dorsal column flanked by two dorsolateral columns and two lateral columns. Uniancres also extend dorsally across mouth rim. Ten epidermal glands per side. Up to nine TbA per side inserting directly on body surface at mouth rim. TbL absent. At least 43 TbVL per side beginning at PIJ and extending onto the outer edges of the caudal lobes. Two TbP insert terminally on caudal lobes, two insert medially. Hermaphroditic, with paired testes and single glandular caudal organ. Rosette organ on left dorsolateral side of body; single ovary present.

Etymology.

Named after the region of origin, referring to the Caribbean (Latin adjectival ending: ensis; caribbeanensis).

Description.

The description is based on the holotype (adult, 625 µm long), with ranges given from specimens measured in vivo. Body strap-shaped and 425-625 µm long (Fig. 1A). Mouth region narrow; body inflates at U04, narrows again at U08, and widens toward the trunk. Widths of mouth at U04/pharynx region at U08/PIJ at U36/trunk at U50/caudal base at U92 are 30/67/105/125/20 µm. Pharynx 23 8 µm long with pharyngeal pores at U32. Dorsal rim of oral hood, ca. 10 µm wide, free of cuticular spines and fringed with numerous mobile cilia and few stiff sensory hairs to 10 µm long. Epidermal glands to 18 µm diameter and to 10 per side. Ventral locomotory cilia present as a complete field beginning at ca. U08 and extending to the caudum (Fig. 2B).

Cuticular armature.

Cuticular spines evident at low magnification and arranged around the periphery of the head, along the trunk and on the caudal lobes (Figs. 1, 2). Spined- and spineless scales present. Approximately 10-12 oral uniancres line the dorsal periphery of the head behind the “naked” region of the oral hood (Fig. 1B). Uninacres slightly staggered in position; uniancres increase in size from medial position (10 µm long) to a lateral position along head (U06, 23 µm long). Uniancres in lateral and dorsolateral positions continue along the trunk as individual columns. The trunk contains a total of five columns of uniancres: one dorsal, two dorsolateral, and two lateral columns (Figs. 1A, 2A). Sixteen uniancres in dorsal column begin at U08 and extend to U80, increasing in size from 20-50 µm long down the length of the body, and with a slight bend or posterior curvature at the apex (Fig. 3B). Dorsolateral columns of ca. 14-16 spines that increase in length along the trunk, from 17-35 µm long and with a slight posterior curvature or distinguishable bend (Fig. 2D); column ends at U85. Lateral columns of 23-26 spines that increase in length along the trunk, from 20-35 µm, and mostly with a straight shape but oriented in a slight posterior direction; column ends at U87. Five small uniancres present on each caudal lobe, 8-20 µm long, in somewhat dorsolateral position (Fig. 1C). Cuticle between uniancres present as spineless scales. Scales of various shape; most dorsal scales have an obtuse triangular shape with the apex pointed posteriorly; some ventral scales same shape as dorsal scales; others of varying shapes (Figs. 1B, 2E, 3A). Center of each scale with a triangular or eye-shaped depression. Scales ca. 15 µm wide and arranged in 5 columns on dorsal surface; ventral surface also with scales but the number of columns was undetermined.

Adhesive tubes.

Anterior adhesive tubes (TbA), 8 per side to 12 µm long, distributed along the mouth margin in a single row (Fig. 2B,C). TbL are absent. TbVL arranged in bilateral columns, to 23 µm long, begin at PIJ and extend posteriorly on to the lateral edge of the caudal lobes; tubes on caudal lobe edges each ca. 15 µm long (Fig. 2B). TbP distributed on caudal lobes as two terminal tubes to 16 µm long and two medial tubes on the inner edge of the caudal lobes to 12 µm long.

Digestive tract.

Mouth terminal to 30 µm wide. Pharynx to 238 µm long with pharyngeal pores at base around U32. Intestine narrow and tapering toward posterior end. Anus at U88.

Reproductive system.

Hermaphroditic, with paired testes at PIJ. Vasa deferentia extend posteriorly, but their point of termination was not observed. Glandular caudal organ, ca. 30 µm long, at U90 (Fig. 2A). Rosette organ, ca. 27 µm diameter, present at U42 on left, dorsolateral surface. Glands of the rosette organ stain intensely with OsO4 (Fig. 3C). Single egg present, ca. 57 µm x 100 µm (Fig. 1C).