Adhesive Tubes Research Articles

Tetranchyroderma sardum, A new species of the family Thaumastodermatidae (Gastrotricha, Macrodasyida)

Abstract Tetranchyroderma sardum, a new species of macrodasyid gastrotrich, was found in litoral sand from Sardinia. It is characterized by: 1. two pairs of cephalic tentacles, one rod‐like and the other knob‐like; 2. twenty‐two pairs of ventrolateral adhesive tubes; 3. three furcal adhesive tubes and 4. thirteen longitudinal rows of pen‐tancres. T. sardum closely resembles T. esarabdophorum and T. anten‐natum, both collected from the Mediterranean Sea.

Two new interesting genera of Gastrotricha (Macrodasyida and Chaetonotida) from the Brazilian freshwater psammon

Two new genera and species of Gastrotricha are described from the psammon of a freshwater body in Brazil: Redudasys fornerise and Arenotus strixinoi. The former is the first undoubted member of the order Macrodasyida recorded from a freshwater environment. It is characterized by the reduction in number of adhesive tubes, the absence of male sexual organs and the presence of a well-developed protonephridial system. The latter belongs to the order Chaetonotida (family Chaetonotidae) and is characterized by the uniform body covering with a thick layer of soft homogeneous cuticle. A possible mode of colonization of fresh waters by marine Macrodasyida, involving colonization of freshwater areas underlying marine beaches, is discussed.

Musellifer sublitoralis, a New Genus and Species of Gastrotricha from the San Juan Archipelago, Washington

Musellifer sublitoralis n. g., n. sp. is described as a marine gastrotrich. Diagnosis of the family Chaetonotidae Zelinka, 1889 is emended to include this new genus. Diagnosis of the genus Musellifer: Chaetonotidae with head drawn out into a muzzle; caudal furca elongate, having neither joints nor annulations; muzzle surrounded by a ciliary band; cuticle thickened into scales; oral opening terminal. The type species is characterized by subcircular dorsal scales, each bearing a short anterior keel fitted with a posteriorly directed seta, and by the persistence of scales to the furcal tips. Holotype metrics (measurements in JLm): lengths-total 330, muzzle 14, pharynx 63 intestine 123, furca 101; widths-head 33.5, neck 28, trunk 50. Habitat: epibenthic mud, 10-12 m depth, Echo Bay, Seucia Island, San Juan Archi­ pelago, Washington. In each of two summers, 1962 and 1963, I received a single gastrotrich found by John C. Boykin in samples of sublittoral epibenthic mud from the San Juan Archipelago, Washington. Despite intensive sampling of similar habi­ tats during both summers, only two sp,ecimens were found. Although they were collected from stations sep,arated by 30 km of water, the two specimens were of nearly identical morphology. One specimen was collected from the mouth of Echo Bay, Seucia Island (10-12 m depth) and the other from the middle of East Sound, off Rosario Point, Orcas Island (30-32 m depth). These circum­ stances suggest a species of low density and sporadic occurrence. The sp'ecimens represent a new species whose taxonomic characteristics warrant the establish­ ment of a new genus. Order Chaetonotida Remane, 1925 Family Chaetonotidae Zelinka, 1889 EMENDED DIAGNOSIS: Head rounded, lobate, or drawn out into a muzzle; neck somewhat constricted; trunk more or less inflated an,d extended posteriorly into a caudal furca; body without adhesive tubes other than those associated with the posterior end. Two longitudinal bands of normal ventral cilia extend from the head or neck onto the trunk; head with one or two tufts of dorso- or ventro­ lateral cilia or, if a muzzle is present, with a ciliary band surrounding the muzzle; body often with one or two pairs of dorsal bristles. Cuticle smooth or variously thickened, often forming scales or spines. Oral opening terminal or subterminal.