Wingstrandarctus Kristensen 1984

Genus Wingstrandarctus Kristensen, 1984

Diagnosis (following Kristensen 1984): Alae present in all stages except for Halechiniscus - type two-clawed larvae, without procuticular hooks or expansions. Unci simple or with a calcar externum; uncus externus formed from a single piece; uncus internus with accessory spine. Hook-shaped pedunculae present on digitus externus. With two, three or no cephalic vesicles containing bacteria. Seminal receptacles and spermatozoa of the florarctid type. Segmental glands and unicellular epidermal glands present in all segments.

Type species: Wingstrandarctus corallinus Kristensen, 1984.

Additional species: W. intermedius (Renaud-Mornant, 1967) and W. crypticus Renaud-Mornant, 1989.

Remarks. The genus Wingstrandarctus was described by Kristensen (1984) from sediment samples taken along the coastline of One Tree Island, Queensland, Australia at a depth of 2 meters. Apart from the new species of Wingstrandarctus several species of the closely related genus Florarctus were found in the fine coral sand. Since the description of W. corallinus several known but undescribed species of Wingstrandarctus have been found in so different areas as Tromsø, Norway and the Faroe Bank (North Atlantic Ocean), the Mediterranean Sea and in various tropical seas (R.M. Kristensen pers. obs.). Apart from the type species W. corallinus the genus consist of W. crypticus and W. intermedius. Both species were found in coralline sediment from New Caledonia in the south Pacific (Renaud-Mornant 1989). Wingstrandarctus intermedius was first described as Halechiniscus intermedius (see Renaud-Mornant 1967). Features like the lack of procuticular expansion supports found in the ala of most Florarctus allowed Kristensen (1984) to include it as a member of the genus Wingstrandarctus. In most species of Wingstrandarctus and Florarctus the cuticular expansions (alae) are so thin that they are easily overlooked in conventional light microscopy. Although there are only four lateral alae, there appear to be 6, because the first lateral ala is subdivided by a large fold or constriction just anterior to the second pair of legs. All alae are transparent with a fine punctuation. The punctuation represents the pillars inside two layers of outer epicuticle. The tiny pillars are oriented dorsoventrally. This position of pillars is very different from the lateral arrangement of the long pillars in the alae of Actinarctus or Raiarctus.