provided by NMNH Antarctic Invertebrates

Metavargula iota, new species

Figures 70, 71

HOLOTYPE.—USNM 137472, female, length 2.77 mm. Right valve and some appendages in alcohol; left valve dry, gold plated; remaining appendages on 1 slide.

TYPE-LOCALITY.—Vema Cruise 18, station V- 18-113.

ETYMOLOGY.—The specific name from the Greek letter in reference to the relatively small size of the species.


DIAGNOSIS.—Carapace length of female, about 2.77 mm.

Sixth limb: 2 bristles in place of epipodial appendage.

Seventh limb: Each limb with 15 or 16 bristles.

Furca: Each lamella with 8 claws.

DESCRIPTION OF FEMALE.—Carapace elongate with broadly rounded anterior with fairly deep incisur; posterior with backward projecting caudal process; surface smooth.

Infold: Infold broad in area of caudal process and rostrum, narrow elsewhere; infold behind rostrum with about 14 bristles, of these, bristles at inner end of list longer than others; pair of bristles and 3 single bristles present near inner end of incisur; infold of anteroventral and ventral margin with 42 bristles, spacing between bristles wider along posterior part of ventral margin; list on infold in front of caudal process with 23 to 28 fairly large processes and about 8 small bristles (each bristle generally at base of a process); 2 or 3 minute bristles on infold near tip of caudal process.

Selvage: Similar to that on M. adinothrix.

Size: USNM 137472, length 2.77 mm, height 1.39 mm; height 50 percent of length.

First antenna: Joints 1 to 3 similar to those on M. adinothrix; sensory bristle of 5th joint with 10 long proximal filaments 2 distal shorter filaments and bifurcate tip; bristle of 6th joint about one and one-half times length of joint, with few short faint marginal spines. Seventh joint: a-bristle bare, slightly shorter than bristle on 6th joint; b-bristle with 5 short marginal filaments, some pectinate; c-bristle with 8 marginal filaments (tip of bristle missing). Eighth joint: d- and e-bristles bare, about one-half length of c-bristle and about one and one-half times length of b-bristles; f- and g-bristles long with about 10 marginal filaments (some pectinate) and bifurcate tip.

Second antenna: Protopodite and endopodite similar to those on M. adinothrix. Exopodite: joints 3 to 9 with basal spines; basal spines smaller on proximal joints; lateral spine on 9th joint much larger than that on 8th; 9th joint with 4 bristles, 3 long, 1 short; joints 2 to 8 with short spines forming row along distal margin; bristle of 2nd joint with about 14 minute spines along ventral margin and about 2 faint proximal spines along dorsal margin, bifurcate tip reaching 8th joint; long bristles on exopodial joints 2—9 with natatory hairs.

Mandible: Coxale endite similar to that on M. adinothrix. Basale: dorsal margin with 1 bare bristle and 2 terminal bristles, shorter of these bare, other with short marginal spines; ventral margin with 2 a-bristles, both with short marginal spines, 1 short b-bristle with short marginal spines, 2 c-bristles (proximal of these short bare, other long with long proximal and short distal marginal spines), and 2 d-bristles (proximal bare, distal long spinous). Exopodite and endopodite similar to those on Af. adinothrix.

Maxilla: Coxale with stout plumose bristle. Exopodite broad with usual 3 bristles, proximal 2 bristles with long marginal proximal hairs, terminal bristle with few long spines proximally and short spines distally. Endopodite: cutting edge of 1st endopodite joint with 3 rounded teeth; 2 a-bristles present, outer bristle spinous, inner shorter bristle with widely separated short marginal spines; 3 6-bristles present, 2 outer bristles pectinate along inner margins, inner shorter bristle bare; 2nd joint with 4 a-bristles consisting of 2 slender bare inner bristles and 2 long stout outer bristles (outer of these with about 10 teeth along middle of inner margin, other with about 25 teeth along inner margin continuing to tip of bristle), 3 b-bristles, 3 c-bristles, 3 d-bristles, all pectinate.

Fifth limb: Epipodial appendage with 43 bristles; distoanterior process of protopodite small; 1st endite with 7 spinous bristles, 2nd endite with 5 large spinous bristles and 1 small bare bristle, 3rd endite with about 6 bristles; main tooth consisting of 6 pectinate teeth, proximal triangular peg and posterior bristle; anterior side of 1st joint with 4 bristles, 2 long, 2 short, all with spines; 2nd endopodite joint with plumose anterior bristle and numerous bristles on margin adjacent to main tooth of 1st joint; inner lobe of 3rd joint with 3 bristles, outer lobe with 2; 4th plus 5th joints united with small spined peg between bristle clusters; 4th joint with 4 or 5 bristles, 5th with 2; small hirsute process present on outer edge of 5th joint near base of bristles observed on right limb only; 3rd to 5th joints hirsute.

Sixth limb: Shape of limb similar to that of M. adinothrix; 2 bristles in place of epipodial appendage; 1st endite with 3 bristles, 2 medial, 1 terminal; 2nd endite with 5 bristles, 3 medial, 2 terminal; 3rd and 4th endites each with 3 terminal bristles; 4th endite slightly longer and narrower than 3rd; end joint with 13 bristles on left, 15 on right of USNM 127472; 2 posterior bristles on end joint hirsute, others with long proximal and short distal spines; medial surface of endites and end joint hirsute; ventral margin and end joint with lateral spines except at bases of 2 posterior bristles; ventral margin with short space between 3 posterior bristles and remaining bristles.

Seventh limb: Each limb with 15 or 16 bristles: distal group with 9 or 10 bristles, 4 or 5 ventral, 5 dorsal, each with 3 to 8 bells; proximal group with 6 bristles, 3 ventral, 3 dorsal each with 3 or 4 bells; terminal comb with 7 elongate recurved annulate teeth with marginal spines and digitate tips; elongate incurved annulate peg with digitate tip present opposite comb; comb teeth and peg similar type to those on M. adinothrix.

Furca, upper lip, eyes and rodshaped organ: In general, similar to those on M. adinothrix.

Genitalia: Small sclerotized oval with ovoid Pspermatophore attached.

REMARKS.—The well-developed eggs within the body and the presence of spermatophores on the genitalia indicate that the holotype is mature.

COMPARISONS.—The new species is smaller and more elongate than previous species referred to this genus. Measurements are compared below:


Length (mm)

Height (mm)

Height (as % of length)

M. adinothrix, Kornicker, herein




M. optilus, (Kornicker, 1968)




M. ampla, Kornicker, 1970




M. iota, Kornicker, herein




The new species also differs from M. Adinothrix in having fewer epipodial bristles on the 6th limb and larger processes along the list of the caudal process. Metavargula iota has only 8 claws on the furca compared to 9 on M. optilus and M. ampla, and the distal bristle on the 1st joint of the endopodite of the 2nd antenna on M. iota is much longer.

DISTRIBUTION.—This species was collected at only one station, Cook Strait, New Zealand, at a depth of 117 m.”

(Kornicker 1975A, p. 138-141)