Metalanceola, Pirlot, 1931: 12. Pirlot 1939: 12–13. Bowman & Gruner 1973: 21–22. Vinogradov et al. 1982: 88.
Type species. Metalanceola chevreuxi Pirlot, 1931 by monotypy. The unique type, a male measuring about 6 mm, is in the MOM (37 2105), on microscope slides. The type locality is the North Atlantic, near Madeira [31°06’N 24°06’45”W]; Princesse Alice II Stn. 1781 (not 1871 as stated by Pirlot), 0–5000 m, 21 Aug. 1904.
Diagnosis. Body length up to 8 mm. Eyes very small, round. Antennae 1 with large callynophore (narrower in female) with one short and two elongated terminal articles. Antennae 2 a little shorter than A1. Mandibles with relatively broad incisor; body sub-triangular in shape. Maxillae 1; palp without feathered setae on outer distal corner, shorter than outer lobe; outer lobe with straight distal margin armed with three robust setae which are much larger than two similar setae located sub-terminally; inner lobe narrowly oval. Maxillae 2 with relatively narrow lobes, each armed with three strong setae distally. Maxilliped with short, narrow inner lobes. Gnathopoda and pereopods 3 & 4 simple. Pereopods 5–7 with retractile and fully hooded dactyls; spoon-shaped formation hypertrophied.
Monospecific.
Sexual dimorphism. Females have a moderately inflated pereon but it is not especially inflated in males. However, the most significant difference occurs in the structure of the antennae. In males antennae 1 are relatively longer with wider articles and the callynophore is much more robust; in females the callynophore is relatively longer and narrower. Antennae 2 are relatively longer than the first in females, about 0.6x A1, whereas in males they are only about half as long (or less) than the first. In addition, pereopod 7 is stronger in males, the telson is relatively shorter in females and males have small genital papillae, medially near the base of the seventh pereopods.
Remarks. This is a very distinctive genus, as noted above. The strong dactyls of pereopods 3–7 indicate that it probably has a close relationship with a gelatinous host.