Proandricus richerti, 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 : 198-199

Proandricus richerti sp. n.

( Fig. 9 )

Etymology: Named for Mr S. Richert of the KwaZulu-Natal Nature Conservation Service, who assisted Dr A. J. Armstrong in collecting the type material.

Material examined: SOUTH AFRICA: KwaZulu-Natal: Holotype NMSA /Olig.03540 clitellate, Vergelegen Nature Reserve (29º33'41.786"S: 29º29'36.563"E), plateau covered by grass and herbs, burnt in June 2001, in moist soil at depth of 1–30 cm, 31 December 2001. Paratypes NMSA / Olig. 03541 3 clitellate and 13 juveniles found together with holotype; all collected by A. J. Armstrong and S. Richert.

External characters:

General: Body cylindrical, extended laterally in area of tubercula pubertatis. Colour: In life dorsally violet in preclitellar part, ventrally yellowish-white. Alcohol-preserved dorsally with violet tint, ventrally yellowish-grey. Dimensions: Holotype preserved slightly contracted, abscised 125+ mm long, 7 mm wide at segment 10, 9 mm at tubercula pubertatis. Paratypes: Clitellate, abscised, ca. 40–80 mm long; juvenile 30–230 mm long. Segment number: Abscised holotype 255+, juvenile paratypes 360–489. Prostomium: Prolobous, moderate. Segmentation: Secondary annulation present on preclitellar segments; 1 and 2 clearly separated one from another, short, simple, both with irregular longitudinal grooves; 3 simple, longer than 1 or 2; 4–8 with two simple ringlets, similar in size and appearance; 9 with two ringlets, second shorter than first; 10–12 simple; postclitellar simple, randomly annulated. Setae: Closely paired; moderate in size; first pairs on 3; on 4–9 on first ringlet; on postclitellar segments aa> bc, ab = cd. Nephridial pores: Conspicuous, in cd setal lines; first pair in 2/3 intersegmental furrow. Female pores: Not observed. Male pores: Probably in 17/18 intersegmental furrow in area of tubercula pubertatis, where there are small depressions. Spermathecal pores: Externally not detected; during dissection found in intersegmental furrows 11/ 12 and 12/13.

Clitellar region ( Fig. 9 ): Clitellum: On holotype and mature paratypes marked by brownish colour on segments 13–23; ventral edges in line of tubercula pubertatis. Tubercula pubertatis: On holotype large, rectangular pads with rounded corners, on 1/n16–20; rimmed at dorsal borders; on paratypes markedly less than on holotype, rimmed dorsally. Papillae: Very small tubercles in line of ab setae on variable segments 10–12.

Internal characters:

Septa: 4/5 5/6 6/7 very thin; 7/8 and 8/9 much thickened, muscular, firm, similar in size and appearance. Gizzard: In 7, elongated, muscular. Calciferous glands: In 9; moderate in size, laterally; separated dorsally and ventrally. Intestine: Commences in 13; in segments 23–28 paired elongated diverticula. Typhlosole: Commences immediately with intestine as thin tube, gradually enlarging and becoming U-shaped, thick structure; in abscised holotype terminates in segment 178; in juvenile paratype consisting of 489 segments and terminates in 180, leaving over 300 segments with no typhlosole. Dorsal blood vessel: In segments 4–7 double in posterior parts, separated; in 8 double, widely separated; in 9 double, large, cordiform; single when crossing septa, in 10 and the following segments; 4–8 thin tubes; in 9–11 enlarged, moniliform. Nephridia: Meganephridia ; coiled loops with short, thick V-shaped caeca.

Reproductive organs: Spermiductal funnels: Proandric arrangement (in segment 10); in holotype moderate in size, iridescent. Also in paratype with clitellum marked only by brown colour, a trace of iridescence was observed in small spermiductal funnels; both funnels closely connected with seminal sacs at posterior part of segment 10. Vasa deferentia: Single ducts commence at dorsal parts of spermiductal funnels, and run backwards almost medially at each side of the body to segment 17, where they enter body wall. Seminal vesicles: One pair of moderate sacs, anteriorly connected at septum 10/11 with spermiductal funnels, extending backward to segments 11 and 12; in holotype both vesicles are elongated and of equal size, but when crossing septum 11/12 becoming narrower; in paratype both vesicles smaller than in holotype, extending equally through segments 11 and 12 (probably the differences in size and shape can be accounted to different states of maturity). Spermathecae: Close to septa 11/12 and 12/13; variable in shape and size, very small, bent ampullae; 3–4 at each side in segments 12 and 13. Ovaries: Not observed. Genital glands: In segment 10 two simple, elongated, straight, narrow glands; in segment 21 similar in size to glands of segment 10, but twice-folded and bent posteriorly; in segment 22 only one gland, finger-shaped.

Biological notes: The type locality is located in the Drakensberg foothills at ca. 1500 m, where there is a deep valley with steep hillsides covered by indigenous bushes and open grassveld ( Pooley & Player 1995). During earlier years the area was used for grazing, but has never been ploughed or been arable land. The types were found on the plateau covered by grass and herbs, and were dug out at a depth of 1–30 cm from moist soil and from between grass roots.A large part of the grassland had been burnt about six months previously. Earthworm presence between the roots of burnt grasses indicates an ability to migrate into deeper soil during unfavorable conditions, and a return to the top layer when conditions permit. The species is probably restricted to the outskirts of the Drakensberg range.

Discussion: P. richerti belongs to the P. colletti species-group, having only septa 7/8 and 8/9 thickened, and spermathecal pores in intersegmental furrows 11/12 and 12/13. Similar to bergvillensis in the backward extension of the seminal vesicles, and relatively short typhlosole. However, extension of the seminal vesicles in richerti probably does not cross septum 12/13.Also the shape of the tubercula pubertatis differs in both species. The length of the typhlosole in this new species is worthy of special note, as it is exceptionally short, occupying only a little more than one-third of the body segments. In the other species of the genus, the typhlosole extends to about two-thirds of the segment number, leaving only about one-third of segments without typhlosole. The presence of diverticula is also characteristic of this species.

Figures

Figs 8–9. Proandricus species. Clitellar region, ventral view. 8. P. michelleae sp. n. 9. P. richerti sp. n. [C= clitellum; T = tuberculum pubertatis.]