Slender Slaters

Laevophiloscia Wahrberg, 1922

Fauna Portal Genus Number: 602

(after Vandel 1973): The genus Laevophiloscia can be defined as follows: Somatic characters: a) elongated and narrow body, b) cephalon: one supra-antennal line, no frontal line, c) pereonites with a straight or slightly convex posterior edge (I and II), or slightly concave (VI and VII), d) pleon set back on the pereon; neopleurons reduced, barely visible, or sometimes almost invisible in dorsal view, e) triangular telson, with a rounded apex, and straight or very slightly concave lateral edges. 

Integument characters: a) elongated glandular fields, containing numerous pores, b) lateral noduli: examination of the position of the lateral noduli in the species we have studied proves the homogeneity of the genus Laevophiloscia. The differences observed between species are extremely small. The first characteristic—quite exceptional—is the presence of two lateral noduli on the first pereonite; the first nodulus is anterior, the second, posterior. The second characteristic of the genus Laevophiloscia is the location of the noduli of pereionites II to VII, which are all inserted at the posterior angle of the segment. The curve d/e is very flattened in all species of the genus Laevophiloscia. This arrangement is a consequence of the reduced width of the pleurepimers, which prevents significant displacements of the lateral noduli in the transverse direction. It is also the reduced width of the pleurepimeres that gives these isopods their elongated appearance.

Appendages: a) antennule bearing aesthetascs arranged in several tiers, one of which is terminal, b) straight mandible bearing two penicilli; left mandible bearing three penicilli. The molar process is dichotomized, c) maxilla: internal endite ending in two penicilli. External endite bearing five entire horny teeth and five hyaline teeth, four of which are cleft at their tips and one entire, d) maxilliped: quadrangular endite, bearing two teeth on the external side, and, on the internal side, a strong spine extending beyond the distal edge of the endite. No penicillium, e) pereopods: a grooming apparatus on the carpos and propodos of the first pereiopod.

Male sexual characteristics: a) pereopods lacking sexual differentiation, b) first pleopod: endopodite ending in an outwardly directed point, c) second pleopod: end of the endopodite showing a tendency to become flagelliform.