Family VIBILIIDAE Dana, 1852

Diagnosis

Body length 5­20 mm, slightly flattened laterally, cuticle relatively thick, and smooth (except for minute cuticular markings). Head rather small, rarely longer than first two pereonites, subquadrangular, with weakly developed rostrum; anterior margin with small notch about three­quarters from dorsal margin, often obscured by first pereonite. Eyes small to moderate (absent in V. caeca) but never occupying most of head surface. Pereonites all separate. Coxae separate from pereonites. Antenna 1 longer than head; peduncle short, 3­segmented; first flagellar article (callynophore) enlarged, spatuliform with slightly concave medial surface, with dense brush (two fields) of aesthetascs; remaining flagellar articles rudimentary, reduced to one or two minute articles. Antenna 2 inserted on anterior surface of head in small, almost lateral pocket; composed of 5­9 (rarely 2­4) slender articles; slightly longer than A 1 in males, slightly shorter than A 1 in females. Mandibles with palp in both sexes, third article of palp longer (Vibilia), or shorter than second (Vibilioides), molar process well developed (Vibilia), or reduced to simple conical projection (Vibilioides). Maxillae 1 with palp and well­developed outer lobe, inner lobe present as small round process. Maxillae 2 consisting of two small lobes in Vibilia, reduced to single lobe in Vibilioides. Maxilliped with short rounded inner lobe, about half as long as outer lobes. Gnathopod 1 simple. Gnathopod 2 chelate. Pereopods 5 & 6 the longest. Pereopod 7 reduced in size, with enlarged basis, with full compliment of articles, with dactylus modified, clavate or knife­shaped (Vibilia), or with only three small articles in addition to basis (Vibilioides). Uropods with articulated exopods and endopods. Telson shorter than peduncle of U3, triangular, or semicircular. Gills on pereonites 2­6. Oostegites on pereonites 2­5.

Two genera: Vibilia and Vibilioides.

Remarks

Bowman and Gruner (1973) synonymised Vibilioides with Vibilia, believing that the difference in the morphology of pereopod 7 was insufficient to maintain generic status. However, as Vinogradov et al. (1982) point out, the morphology of the mouthparts of Vibilioides differs considerably from those of Vibilia. Generally they are reduced; the mandibular molar consists of a simple conical projection; the first maxillae have a muchreduced inner lobe and the second maxillae are rudimentary. Thus, Vibilioides should be maintained.