Caridina malawensis Richard & Clark, 2009, sp. nov.
Creators: name: Jasmine Richard
name: Paul F. Clark
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Atyidae
Caridina
Caridina malawensis

description: Caridina malawensis sp. nov.
(Figs. 38, 39)
Material examined. Holotype: ♀ ovig. Malawi rocky shore of Lake Malawi, 20.9.– 20.11.1974, coll. P. Lamarque and C. Gosset, pres. Y. Therezien, RMNH D 30477.
Description. Total length: 17 mm. Carapace length: 2.95 mm.
Rostrum (Fig. 38a, b): equal to antennular peduncle. 2.72 mm in length. 0.92 × carapace. 19 teeth on dorsal margin leaving 0.29 of length unarmed only interrupted by single tooth. 2 post-orbital teeth. 9 teeth on ventral margin leaving short unarmed distal end. Tip bifid. Formula (2) 19+1/9.
Antennular peduncle (Fig. 38e): 0.8 × carapace. Stylocerite 0.6 × length of basal segment. Anterolateral teeth of basal segment 0.36 × second segment. 9 segments bearing aesthetascs.
Mandible (Fig. 38c, d): asymmetrical, with long thin filament attached to the right mandible. (It is not clear whether filament on left mandible was lost).
First pereiopod (Fig. 39a): dactylus 1.6 × palm of propodus. Chela 2.2 × long as broad. Carpus 2–2.15 × long as broad with deep excavation.
Second pereiopod (Fig. 39b): dactylus 1.33 × long as palm of propodus. Chela 3 × long as broad. Carpus 4.6 × long as broad.
Third pereiopod (Fig. 39c, d): dactylus 2.6 × long as broad and with 8 spines (including terminal spines). Propodus 5.4 × long as dactylus and 12.5 × long as broad, with 9 spines along posterior margin. Carpus 0.5 × long as propodus, with minute spines on inner margin. Merus 2.4 × carpus length. Merus with 1 spine on posterior margin.
Fifth pereiopod (Fig. 39e, f): dactylus 2.6 × long as broad with 32 spines in a comb like fashion on inner margin. Propodus 13.3 × long as broad and 4.7 × long as dactylus with 6 spines along posterior margin. Car-
pus 0.46 × propodus length and with minute spines along inner margin. Merus 1.94 × carpus length and with 2 spines along inner margin.
Setobranchs: 1 on all pereiopods.
First female pleopod (Fig. 39g): endopod 0.55 × long as exopod.
Eggs (Fig. 39h): 55, 0.59 × 0.35 mm in size.
Sixth abdominal somite: 0.72 × long as carapace.
Telson (Fig. 39i, j): as long as sixth abdominal somite. Dorsal spines 4 pairs (including subterminal spine). Telson tapering towards triangular medial point. Three pairs of alternately short and long thinly plumose spines on posterior margin.
Uropod (Fig. 39k, l): 9 diaeresis spinules.
Preanal carina (Fig. 39m): unarmed.
Remarks. The single ovigerous female holotyope of C. malawensis, from Lake Malawi, Mozambique, is unique with many distinguishing characters. Among these, of considerable interest is a long filament from the right mandible (Fig. 38c, d) that protrudes out into the anterior region of the cephalothorax. However, it is not clear if a filament was originally also present on the left side, but which is now lost. This particular character requires further analysis being known only from a single specimen. It would be interesting to study the function and significance of the long filament (Fig. 38a, c, d), as it may provide clues on the feeding mechanism of the species.
The holotype of C. malawensis is unique in other characters: rostrum equal to the antennular peduncle; 19 teeth arranged on dorsal margin of the rostrum proximally, leaving the distal dorsal margin unarmed, interrupted by a single tooth; on the ventral rostral margin bears 9 teeth arranged up to the bifid tip; the dactylus of the fifth pereiopod has 32 spines; and the posterior margin of the telson is triangular with short spines that are alternatively short and long. The ovigerous holotype carries 55 eggs, of 0.59 × 0.35 mm size.
Etymology. Named malawensis, after Lake Malawi.
description: Published as part of Jasmine Richard & Paul F. Clark, 2009, African Caridina (Crustacea: Decapoda: Caridea: Atyidae): redescriptions of C. africana Kingsley, 1882, C. togoensis Hilgendorf, 1893, C. natalensis Bouvier, 1925 and C. roubaudi Bouvier, 1925 with descriptions of 14 new species, pp. 1-75 in Zootaxa 1995 on pages 69-72, DOI: 10.5281/zenodo.1455866