Lanceola sphaerica

Lanceola sphaerica (Vinogradov)

(Fig. 13)

Lanceola clausi var. sphaerica Vinogradov, 1957: 196, fig. 6.

Lanceola sphaerica Vinogradov 1970: 383, 386–388, figs 1, 2. Vinogradov et al. 1982: 73–75, fig. 20.

Type material. This species was first described as a variety of L. clausi from two damaged specimens, a mature female of length 8 mm and a male of length 9 mm, both caught in the Kurile-Kamchatka region of the North-West Pacific. The female from Vityaz Stn. 2076 [43°39’N 149°24’E] at 4200–7800 m and the male from Vityaz Stn. 2208 [49°23’N 158°45’E] at 0–6500 m. Later, Vinogradov (1970) established it as a full species with the availability of a well-preserved male of length 5.5 mm from the same general area; Vityaz Stn. 5626 [45°11’N 152°28’E] at 3000–4000 m. All three specimens are in the ZMMU (Mb–1051 to Mb–1053 respectively).

Diagnosis. According to Vinogradov (1957 & 1970). Only known from the above three specimens; females reach maturity at 8.0mm. Habitus like L. clausi but pereon more inflated, especially in females. Head without rostrum. Eyes very small, reniform, without crystalline cones. Antennae 1 as long as head and first pereonite combined; terminal article elongate, slightly longer than twice preceding article. Antennae 2 relatively short, slightly longer than A1. Pereopod 3 similar to but slightly shorter than P4; basis length slightly more than twice merus (slightly less for P4); carpus slightly longer than merus; propodus length 1.2x carpus or longer; dactylus relatively long, length 0.4–0.5x propodus (slightly shorter in female). Pereopods 5–7 with retractile, mostly hooded dactyls. Pereopod 5 slightly shorter than P4; basis length 1.8x merus; carpus slightly longer than merus; propodus slightly longer than carpus, in males slightly expanded distally with strong setae distally on anterior margin; dactylus relatively long (especially in males) pressed against propodus, forming indistinct subchela in males, less so in females. Pereopod 6 slightly longer than P4, or P5; basis length 1.6x merus; carpus length 1.2x merus; propodus length 1.6x carpus. Pereopod 7; length about 0.7x P6; basis about twice length merus; carpus length about 1.4x merus; propodus length 1.8x carpus, slightly longer than basis. Peduncle of U1 does not exceed limit of peduncle of U2. Peduncles of U1–3 relatively broader in females (particularly U3). Uropod 3; peduncle width about 0.4x length in males. Telson pointed; length 0.6–0.7x peduncle of U3, marginally shorter in smaller specimens.

Colour of living specimens not recorded.

Remarks. I have not seen any specimens of this species but accept its validity based on the observations of Vinogradov (1957 & 1970).

This species is distinguished from all its congeners by a combination of several characters; the inflated pereon (especially in females), the relatively long dactyls of pereopods 3–7 (especially pereopods 3 & 4), the structure of pereopod 5 becoming subchelate in males and the relatively short telson. It is most similar to L. clausi in the general habitus and relative lengths of the pereopoda but is readily distinguished by the slightly more inflated pereon and the relatively longer dactyls of pereopods 3–7. In the long dactyls of pereopods 3 & 4, it resembles L. longidactyla Vinogradov, 1964 but in that species the dactyls are relatively longer and pereopod 5 is not modified. It also resembles L. chelifera Vinogradov, 1970, especially in the modification of pereopod 5 but in that species the dactylus of pereopod 5 is not retractile or hooded and the structure of pereopods 3 & 4 is completely different.

Distribution. Only known from the Kurile-Kamchatka region of the Pacific Ocean, from three specimens as detailed above.