dcsimg

Comprehensive Description

    Description
    provided by NMNH Antarctic Invertebrates

    “Sub-Genus Vargula n. sub-gen.

    Cypridina (part.), autorum.

    Description: —Shell: — The shape is somewhat, though rather slightly, different in males and females. — It is oval, with or without a weakly developed posterior corner. The rostral incisor is most frequently narrow and comparatively deep, only in exceptional cases quite shallow. Near the inner edge of the incisur there are two medial bristles situated close to each other. With rather strong calcification. All the species hitherto known are rather large.

    First antenna: -- This is long and slender and eight-jointed. The sensory bristle of the fifth joint has thirteen sensory filaments. The b- and c-bristles of the males are generally characterized by quite the same modification as described above, p.223, for the sub-genus Doloria; in exceptional cases the former of these two bristles has only one filament with a series of small distal suckers; see Cypridina mediterranea, G.W. MÜLLER, 1984, pl.2, fig. 20. The end bristles are sometimes rather slightly longer in the males than in the females, sometimes in the former sex bristles f and g are considerably longer than in the latter.

    Second antenna: -- The protopodite has a medial-distal bristle. The bristle on the second joint of the exopodite is rather powerfully developed. The natatory bristles on the third to ninth joint have no trace of spines. The third to ninth joints have basal spines. The endopodite is similarly developed in males and females, being either comparatively well developed, rather elongated and three-jointed or more or less reduced, with a reduction in the number of joints. Thi bristle of the end joint is comparatively long.

    Mandible: -- Protopodite: The endite on the coxale is weakly bifurcated distally; some of its spines are rather strong, especially those situated medially-distially; at least some are arranged in rather distinct groups. Apart from the little bristle situated dorsally on this process this joint has no bristles. Basale: Of the ventral bristles one d-bristle is very long, has numerous long secondary bristles and is furnished with short hairs distally; the others are of moderate length or short and have short fine hairs or are naked. Dorsally this joint has three bristles. Endopodite: The first joint has four bristles ventrally. The end joint has seven bristles, of which the middle ones are the most powerful, claw-like, and of about the same length and strength as each other.

    Maxilla: -- Protopodite: The coxale has a single bristle dorso-distally with long, fine hairs. There is a single bristle proximally on the outside of the third endite. The bristles on the boundary between the basale and the first endopodite joint vary somewhat; sometimes three are developed, on close to the exopodite, one medially at about the middle of the palp and one on the anterior edge of the palp; this last bristle is, however, sometimes missing. There is a rather large lamelliform epipodal appendage dorso-distally on the coxale. The exopodite is comparatively well developed, with close, fine, long hairs and not displaced distally. The endopodite is broad and of moderate length.

    Sixth limb: -- The second exopodite joint is rather short, somewhat rounded and has numerous bristles. Its posterior bristles do not dominate strikingly over the other bristles. (G.W. MÜLLER states, 1894, p.68, that the epipodal appendage of the protopodite in the genus Cypridina, sensu G.W. MÜLLERI, is always characterized by four bristles; that this is not the case is shown by the descriptions of the species given below.)

    Seventh limb: -- This is furnished with rather numerous cleaning bristles, a large number of which are placed close together distally, the rest scattered irregularly along the distal part of the limb. With regard to the position of these latter bristles it is to be noted that only exceedingly seldom or perhaps never is there more than one bristle on the same side of the same joint. The end comb consists of a moderate number of rather strong teeth, some rather long, distally rounded or more or less pointed distal teeth, smooth except for a little secondary spine at the middle of each side, some somewhat shorter and broader proximal teeth, cut off rather transversally distally. Dorsally, close to the end come, the wall of the limb is somewhat thickened and has a more or less weak chitinous wart. It is also somewhat concave at this point, the depth of the concavity varying. The dorsal and ventral walls of the cavity are not moveably joined to each other, but at least in some forms they may, however, be pressed somewhat towards each other like a jaw, when the distal teeth of the end comb are pressed in towards the dorsal wall of the cavity (see fig. 14 of C. (V.) megalops). This compression is effected by a paired short, powerful muscle, which issue proximally somewhat proximo-dorsally of the point of the limb and is fixed distally to the bottom of the cavity. This muscle is sometimes absent; whether in this case the distal teeth can be pressed in or not I am not able to decide, as I have only preserved material of these forms at my disposal; I merely point out here that these teeth were not pressed in on any of the numerous specimens of species without this muscle that I investigated, while they were pressed in very often on specimens of species with it.

    Furca: -- The lamella are moderately elongated. The number of claws from about nine to eleven, without, or in some case with, division into main claws and secondary claws.

    Upper lip: -- This has three glandular fields: An anterior one, unpaired, moderately large, in which the exits of the glands are directed obliquely forwards and downwards, and two ventrally. The two latter are sometimes comparatively small and situated distally on a couple of large tusk-like processes, sometimes they are of moderate size and not raised; even in the last-mentioned case, however, the three fields of glands are separated from each other by rather deep grooves. There is an unpaired protuberance on the front between the upper lip and the frontal organ.

    The rod-shaped organ is well developed and rather short and thick.

    The lateral eyes vary in their development; sometimes they are almost completely reduced.

    Remarks: -- Besides the three species described below we have probably to include in this sub-genus a rather large number of species grouped together by G.W. MÜLLER in his work of 1912 under the generic name Cypridina. Of these species I merely mention here:

    Cypridina mediterranea, O.Costa, 1845 (G.W. MÜLLER, 1894, p.206, pl. 2, figs 1, 2, 4, 5, 8-20, 22-27, 33.)

    “ dorsoserrata, G.W. MÜLLER, 1908, p. 83, pl. IV, figs. 103, 5-10.

    “ Sarsi G.W. MÜLLER; G.O. Sars, p.43 (215), pl. III, figs. 1,2, pl. VIII, figs. 6, 7.

    “ Vanhöffeni, G.W. MÜLLER, 1908, p. 82, pl. V, figs 1-8, 13.

    “ squamosa, G.W. MÜLLER, 1894, p.207, pl.2, figs 3, 6, 7, 21, 28-32, 34-36.

    “ Hilgendorfi, G.W. MÜLLER, 1890, p.228, p. XXV, fig 9, pl XXVI fig. 1-3, pl. XXVII, fig 30.

    A closer examination of these species will probably make it necessary to widen somewhat the above diagnosis of this subgenus.

    Type.

    As the type of this sub-genus I consider the form described below under the name C.(V.) norvegica.” (Skogsberg 1920, p.245-247)

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    txt_AI_2887_GenDesc