Proandricus dwesa, 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 : 190-192

Proandricus dwesa sp. n.

Figs 4–5

Etymology: Named after the type locality, Dwesa .

Material examined: SOUTH AFRICA: Eastern Cape: Holotype NMSA /Olig.02807 well preserved, with distinct clitellum and slightly developed tubercula pubertatis, Dwesa Nature Reserve (32.304ºS: 28.828ºE) coastal forest, under fallen log. Paratype: NMSA / Olig. 03524 with tubercula pubertatis not clearly marked, collected together with holotype. All material collected by D. G. Herbert of the Natal Museum’s Department of Malacology .

Description based on holotype and paratype.

External characters:

General: Body cylindrical. Colour: In life dorsally dark-grey with violet tint, ventrally yellowish-grey; alcohol-preserved dorsally and ventrally grey. Dimensions: In life, not stretched 350 mm long, in preclitellar area 10 mm wide, 12 mm at clitellum; preserved and contracted, holotype 243 mm long, 10 mm wide at segment 10, 15 mm at clitellum; paratype 250 mm long, 14 mm at clitellum. Segment number: Holotype 208, paratype 204. Prostomium: Prolobous, moderate in size; 1 and 2 simple, short with longitudinal grooves; 3 simple, as long as first ringlet of segment 4; 4–9 with two simple ringlets, first longer than second; 10 and 11 short, simple, similar in size to first ringlet of segment 9. Setae: Large; closely paired on segment 3, and on first ringlets of segments 4–9; on clitellar segments paired more distantly than preclitellarly; postclitellarly closely paired with aa> bc, ab similar to cd. Nephridial pores: Conspicuous in cd setal lines. Female pores: In 14, medially between setae aa. Male pores: Difficult to trace; in area of tubercula pubertatis are small depressions in intersegmental furrow 14/15, and are probably male pores. Spermathecal pores: In intersegmental furrows 11/12 and 12/13.

Clitellar region ( Fig. 4 ): Clitellum: Saddle-shaped, segmented with simple segments; extending onto segments 11–22, clearly bordered anteriorly and posteriorly, with ventral borders below cd setae. Tubercula pubertatis: Not distinctly marked, however, on ventral clitellar edges of segments 1/n14–1/n19 are oblong, segmented ridges, with medial shallow, longitudinal furrows and narrow rims. Papillae: Paired, small indistinct swellings in the line of ab setae; first pair on first ringlet of segment 9, the following on segments 10–26.

Internal characters:

Septa: 4/5 5/6 6/7 thin; 7/8 thickened moderately, muscular; 8/9 thickened the most, muscular, nearly twice size of 7/8; the following septa thin, but firm. Gizzard ( Fig. 5 ): In 7, bell-shaped, muscular, posteriorly soft. Calciferous glands: Large, in 9–10, ventrolaterally, distinctly separated dorsally. Intestine: Commences in 13. Typhlosole: Commences in 20 as large U-shaped tube; extends to nearly 2/3 of body length; terminates in holotype in segment 130, in dissected paratype in 128. Dorsal blood vessel: In 5–6 partly double, very close; double in whole length of segment 7, but very close; in 8 double, widely separated; in 9 double, cordiform; single when crossing septa and posterior to 9. Paired dorsoventral vessels: Very thin vessels in 5–8; in 9–11 enlarged, moniliform. Nephridia: Meganephridia ; large coiled loops, and large V-shaped caeca; in some clitellar segments caeca extends laterally, becoming ribbon-folded; postclitellarly caeca simple.

Reproductive organs: Spermiductal funnels: Proandric (in segment 10); one pair of funnels enclosed in separated sacs, very close ventrally; at septum 10/11 closely connected with seminal sacs. Vasa deferentia: Single ducts, connected with spermiductal funnels dorsally, run backward to segment 14, where covered by thick tissue of body wall enter male pores at probably intersegmental furrow 14/15. Seminal vesicles: One pair of large sacs anteriorly connected with spermiductal funnels at septum 10/11; in segment 11 extended transversely. Spermathecae: Elongate ampullae, close to septa 11/12 and 12/13; two pairs in anterior segment, three pairs in segment 12. Ovaries: Not observed, covered by folded nephridial loops and large caeca. Genital glands: Not present.

Biological notes: Collected in the Dwesa Nature Reserve, which is controlled by the Eastern Cape Department of Nature Conservation. The Reserve is situated along the coastline in the northeastern part of the Eastern Cape, in the area previously known as the Transkei. There is a mixture of vegetation ranging from coastal forest to open grassland, with Cape and KwaZulu-Natal elements, and a strong afromontane component.

Discussion: Belonging 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. It is noteworthy that although the tubercula pubertatis in dwesa are not well developed, there is some similarity to the shapes seen in belli , which is assigned to the P. belli species-group characterised by thickened three septa 4/5 7/8 8/9. P. dwesa differs from the other species known in both species-groups by an anterior extension of the clitellum on segment 11, and very specific shapes of nephridia.

Figures

Figs 4–5. Proandricus dwesa sp. n. 4. Clitellar region, ventral view. 5. Dorsally dissected preclitellar part of body. [C = clitellum; G = gizzard; S = seta b; SS = septa 7/8 and 8/9.]