Baseodiscus Diesing 1850

• Main Authors: Gibson, Ray, Sundberg, Per
• Format: Text
• Language: unknown
• Published: Zenodo 2002
• Subjects: Biodiversity; Taxonomy; Animalia; Nemertea; Pilidiophora; Heteronemertea; Valenciniidae; Baseodiscus; Antarctic; Antarc*
• Online Access: https://dx.doi.org/10.5281/zenodo.5305857; https://zenodo.org/record/5305857

Genus Baseodiscus Diesing, 1850 Diagnosis Based on accounts of several species of Baseodiscus given by Gibson (1974, 1979, 1985b), the genus may be diagnosed as: Heteronemertea without horizontal lateral cephalic slits, some species with shallow oblique grooves; proboscis with two (outer longitudinal, inner circular) muscle layers and no muscle crosses; rhynchocoel short, rarely more than one-third of the body length; rhynchocoel wall circular musculature not interwoven with adjacent body wall muscles; dorsal Žbrous core of cerebral ganglia forked only at rear into upper and lower branches; nervous system with neither neurochords nor neurochord cells; foregut with distinct subepithelial gland cell layer, usually at least in part separated from the epithelium by delicate longitudinal, circular and/or oblique muscle strands; dermis well developed, with separate outer glandular and inner connective tissue zones; caudal cirrus absent; cephalic glands extensively developed, extending post-orally among the outer body wall longitudinal muscle Žbres; single apical organ present; excretory system mostly with external nephridiopores, but some species with eVerent ducts discharging into lumen of foregut; eyes present, small and numerous; sexes separate. Baseodiscus quinquelineatus (Quoy and Gaimard, 1833) (Žgure 3) Material examined One specimen, from a coral reef at at Rove, close to the White River, just west of Honiara. External features The striking colour pattern of Baseodiscus quinquelineatus , typically comprising Žve longitudinal, slender black or dark brown stripes (three dorsal, two ventral) on a white or cream background, is diagnostic for the species and is shown in Žgure 3. Reported variations in the typical colour pattern include Žve dorsal and two ventral stripes, and examples in which the stripes are irregularly interrupted (see Gibson, 1979: 155–156, Žgure 7C, D). The specimen from Rove was about 100 cm long and 10 mm in maximum width; lengths of over 6 m and widths of more than 15 mm have been reported for this species (Gibson, 1979). Internal anatomy Baseodiscus quinquelineatus was redescribed by Gibson (1979: 153–157, Žgure 7C–F, 8); the morphology of the present material is very similar and no signiŽcant diVerences could be distinguished. Geographic distribution Baseodiscus quinquelineatus has been recorded, under various synonyms (see Gibson, 1995) from the eastern coast of Australia, including the Great Barrier Reef Province, the Torres Straits, Japan, Singapore, Java, Ambon, Timor, New Guinea, the Loyalty Islands and the Solomon Islands. : Published as part of Gibson, Ray & Sundberg, Per, 2002, Some heteronemerteans (Nemertea) from the Solomon Islands, pp. 1785-1804 in Journal of Natural History 36 (15) on page 1790, DOI: 10.1080/00222930110069041, http://zenodo.org/record/5298846 : {"references": ["GIBSON, R., 1974, Two species of Baseodiscus (Heteronemertea) from Jidda in the Red Sea, Zoologischer Anzeiger, 192, 255 - 270.", "GIBSON, R., 1979, Nemerteans of the Great Barrier Reef. 2. Anopla Heteronemertea (Baseodiscidae), Zoological Journal of the Linnean Society, 66, 137 - 160.", "GIBSON, R., 1985 b, Antarctic nemerteans: Heteronemertea - descriptions of new taxa, reappraisals of the systematic status of existing species and a key to the heteronemerteans recorded south of latitude 50 ss S, Zoological Journal of the Linnean Society, 83, 95 - 227.", "GIBSON, R., 1995, Nemertean genera and species of the world: an annotated checklist of original names and description citations, synonyms, current taxonomic status, habitats and recorded zoogeographic distribution, Journal of Natural History, 29, 271 - 562."]}