dcsimg

Description

provided by NMNH Antarctic Invertebrates

Munna nana n. sp.

Text fig. 56, Text figs. 57 a—j.

Diagnosis. Eye-peduncles broad with front margin straight (the ordinary tooth in front of the eyes missing). Lateral margins of the pereion segments rounded. Coxal plates small, rounded. Antennular flagellum consisting of two joints, the last being with one sensory filament. First pereiopods shorter than the others, but stronger and prehensile. First male pleopods strongly tapering towards the end, being about four times broader proximally than distally. Sympodite of second male pleopod prolonged distally into an acute point. Female operculum approximately cordate, very broad proximally but strongly tapering towards the narrowly rounded end; near the distal margin it is furnished with two slender setae.

Description.

Types. Ovigerous female with twelve eggs (Fig. 56), length about 1.2 mm.; male, about i mm. in length.

General shape of body. Body in the female (Fig. 56) broadly oval in outline, with greatest width across the third pereion segment. In the male the first four pereion segments are subequal in width. No setae on the dor­sal surface.

Colour. Whithish to yellowish.

Head (Fig. 56). About as long as the first and second pereion segments plus half the third segment. Frontal part broadly trapezoidal with front margin straight. Insertions for the antennulae and the antennae not very deep. Eye-peduncles broad with very small dark eyes. There is no tooth on the anterior margin of the eye-peduncles.

Pereion (Fig. 56). Segments in the ovigerous female not fully half as long as the second. In the male the first four segments are subequal in length. The lateral margins of the pereion segments are rounded.

Coxal plates small; seen from above their lateral margins are rounded.

Abdomen (Fig. 56). About as long as the last five thoracic segments together, anteriorly with one free segment.

Pleotelson oviform, with distal margin rounded. Greatest width of pleotelson in the female somewhat proximally from the middle. In the male the pleotelson is slightly narrower than in the female and has its greatest width about across the middle. There is a faint elevation on the dorsal side along the middle line.

Antennulae (Fig. 57 a). The two proximal joints of the peduncle are stout and the two following joints small. The flagellum consists of two joints only, of which the last is furnished with one sensory filament and some setae. The flagellum thus differs from the ordinary Munna-type characterized by having one sensory filament on the last and penultimate joints.

Antennae. Broken in all specimens, except a small male about 0.9 mm. in length. In this specimen they are about as long as the body. The first three joints of the peduncle are short, the fourth and fifth long, the fifth somewhat longer than the fourth. The flagel­lum is subequal in length to the peduncle and consists of about ten joints.

Right mandible (Fig. 57 b). Pa1p with the third joint small.

First and second pairs of maxillae (Figs. 57 c and d). Lappets of outer lobe of the second maxillae each with three apical setae.

Lower lip. See Fig. 57 e.

Maxillipeds. Epipodite ovate with distal margin broadly rounded, reaching to about the second joint of the palp.

First pair of pereiopods (Fig. 57 f). Small. Similar in males and females. Carpal joint subtriangular, with one slender seta on the lower margin and two stout setae at the lower distal angle. Propodus ovate, with — as usual in Munna — two setae near the lower margin. For other details see the figure.

The other pereiopods (Fig. 57 g). Increase in length from the first to the last, which is about as long as the body. The merus and carpus have each one two-pointed seta at their upper distal angles, and the propodus has a row of setae of the same kind along the lower margin.

First pair of pleopods, male (Fig. 57 h). Elongate, tapering towards the narrow end. They are proximally about four times broader than distally.

Second pair of pereiopods, male (Fig. 57 i). Sympodites ending distally in acute points.

Operculum, female (Fig. 57 j). Approximately cordate. Very broad proximally, triangularly protracted distally. Distal margin narrowly rounded. Near the distal end there are two small setae.

Uropods. Minute, sub-rectangular. Outer and inner margins almost straight; distal margin slightly rounded and provided with a few setae."

(Nordenstam, Ake, 1933: 222-224)

license
cc-by-nc
author
Nordenstam, Ake, 1933: 222-224
project
Smithsonian National Museum of Natural History - Antarctic Invertebrates

distribution

provided by World Register of Marine Species
St. Paul & Amsterdam Is., 0.6-120 m (Kensley, 1976).

Reference

Van Wyk, B. & Malan, S. (1988) Field Guide to the Wild Flowers of the Witwatersrand and Pretoria Region Struik, Cape Town Pages 54 - 55 (Includes a picture).

license
cc-by-4.0
copyright
WoRMS Editorial Board
contributor
Marilyn Schotte [email]