Proandricus armstrongi, Plisko, 2002

Plisko, Jadwiga Danuta, 2002, Nine new earthworm species of Proandricus Plisko, 1992 from South Africa and Lesotho (Oligochaeta: Microchaetidae), African Invertebrates 43, pp. 183-204 : 200-201

Proandricus armstrongi sp. n.

( Fig. 10 )

Etymology: Named for Dr A. J. Armstrong of the KwaZulu-Natal Nature Conservation Service, who collected and donated this species to the Natal Museum.

Material examined: SOUTH AFRICA: KwaZulu-Natal: Holotype NMSA /Olig.03494 clitellate, well preserved, abscised postclitellarly, collected at Mount Currie Nature Reserve [Kokstad district; an extension of the Drakensberg foothills] (30º29'33.754"S:29º25'25.605'E), under burnt grass, beside a stream, in damp, clayey soil, 31 October 2001, by A. J. Armstrong.

External characters:

General: Body cylindrical, flattened in clitellar region. Colour: Alcohol-preserved dorsally dark-grey, ventrally light-grey. Dimensions: Preserved holotype 84+ mm long, 4 mm wide at segment 10, 9 mm at tubercula pubertatis. Segment number: 177+. Prostomium: Prolobous, small, inverted into buccal cavity. Segmentation: Secondary annulation present on preclitellar segments; segment 1 and 2 short, with longitudinal, irregular grooves; 3 simple, as long as first ringlet of segment 4; 4–6 with two simple ringlets, similar in size and appearance; 7–9 with two annulated ringlets, second shorter than anterior; 10–12 short, simple, with irregular annulation; clitellar simple, longer than preclitellar; postclitellar very short, simple. Setae: Closely paired, minute; postclitellarly aa = bc, ab = cd. Nephridial pores: Conspicuous in cd setal lines; first pair in intersegmental furrow 3/4. Female pores: In 14, slightly above b setae. Male pores: Probably at tubercula pubertatis in furrow 17/18. Spermathecal pores: Minute, in intersegmental furrows 11/12 and 12/13, dorsolaterally.

Clitellar region ( Fig. 10 ): Clitellum: Saddle-shaped, flattened, segmented, yellowishwhite; on 13–22, extending onto small section of segment 23; clearly bordered anteriorly; ventral borders extend to c setal lines. Tubercula pubertatis: On 17–19, large, nearly square pads, segmented, between b and cd setal lines. Papillae: Small paired swellings around ab setae on segment 9 and 23; on segment 9 the swellings extend laterally to c setae.

Internal characters:

Septa: 4/5 moderately thickened, elastic, not muscular; 5/6 very much thickened and muscular, nearly one mm thick; 6/7 very thin, probably even partly lost; 7/8 thickened, muscular, but much thinner than 5/6; 8/9 not thickened, firm; subsequent septa in preclitellar segments elastic, firm, similar in thickness to septum 8/9; postclitellarly thinner. Gizzard: Large, muscular, anteriorly wider than in posterior part. Calciferous glands: Ventro-laterally, in segment 9; dorsally widely separated. Intestine: Commences in 13. Typhlosole: Commences in 13, parallel with intestine, as U-shaped tube. Dorsal blood vessel: In 5 not observed, covered by thick, muscular septum; in 6–7 partly double, close; 8 double, separated; 9 double, cordiform. Paired dorsoventral vessels: 6–8 thin vessels, 9–11 enlarged, moniliform. Nephridia: Meganephridia ; in preclitellar segments large and very much coiled spiral loops, and large V-shaped caeca; postclitellarly smaller loops and shorter caeca.

Reproductive organs: Spermiductal funnels: Proandric arrangement (in segment 10); one pair of funnels enclosed in common sac. Seminal vesicles: One pair, moderately sized; vesicles commence at septum 10/11 and extend into segment 11. Vasa deferentia: Not observed; covered by thick body wall tissues. Spermathecae: Two pairs per segment; coiled or bent tubes, each based on rounded thickenings, close to septa 11/12 and 12/13 respectively. Ovaries: Not observed; covered by thick septum and large coiled loops of nephridia. Genital glands: In segment 9 and 22; anterior pair four-folded, white, short sausage-shaped glands; posterior pair composed of four-folded, yellowish, elongated tubular glands; both pairs corresponding with papillae of segments 9 and 23 respectively.

Biological notes: The type locality is a part of a large extension of the Drakensberg foothills, in the Mount Currie Nature Reserve. The vegetation there comprises montane grasslands, with scrub and Protea veld on the slopes; there are streams with wetland vegetation, small forest patches and clumps of indigenous Leucosidea bushes ( Pooley & Player 1995). The type was dug out from damp, clayey soil under recently burnt grass on the bank of a stream. This clitellate, mature specimen was found in October, after a short period of rainy days, indicating sexual reproduction in spring and early summer.

Discussion: P. armstrongi , having a thickened septum 5/6, and with the position of its spermathecal pores in two intersegmental furrows 11/12 and 12/13, can be assigned to the P. marleyi species-group, comprising only two other species: alatus and marleyi . The new species differs from alatus by having a thickened septum 4/5, the clitellum on 12–23, and the tubercula pubertatis differently shaped. From marleyi it differs by a lack of a thickened septum 8/9, and having other septa much stronger than those observed by Michaelsen (1928) in the type material of marleyi .

Figures

Fig. 10. Proandricus armstrongi sp. n. Clitellar region, ventral view. [C = clitellum;T = tuberculum pubertatis.]