Proandricus crookesi, 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 : 187-188

Proandricus crookesi sp. n.

( Fig. 2 )

Etymology: Named after the late Mr Vernon Crookes who donated the property that is now the Vernon Crookes Nature Reserve, in which this and other earthworm species are protected.

Material examined: SOUTH AFRICA: KwaZulu-Natal: Holotype: NMSA / Olig. 00770 clitellate, Vernon Crookes Nature Reserve (30º18'S: 30º40'E), 6 km N. of Tourist Camp, primary grassland, 22 November 1989 . Paratypes: NMSA / Olig. 02554 1 clitellate, abscised, collected together with holotype ; NMSA / Olig. 00844 1 clitellate, 3 km from type locality, on bank of small water pool, 23 November 1989 ; NMSA / Olig. 00828 2 clitellate, 1 km W. of type locality, dug out from black soil at ca. 45 cm depth. Other material : NMSA/00748 1 clitellate, 8 March 1989 ; NMSA / Olig. 00766 2 abscised anterior parts, 23 November 1989 ; NMSA/00768 7 specimens manifesting clitellum by brown colour, 7 March 1989 ; NMSA / Olig. 00769 1 specimen with abnormally regenerated body part in area of clitellum, 23 November 1989 . All paratypes and other material collected in neighbourhood of type locality by J. D. Plisko .

Description based on holotype and paratypes.

External characters:

General: Body cylindrical. Colour: In life dorsally violet, ventrally yellowish-grey; alcohol-preserved brownish-grey, with violet tint. Dimensions: Holotype somewhat contracted 170 mm long, 6 mm wide at 10, 8 mm at tubercula pubertatis; clitellate paratype 120 mm long, 6 mm wide at 10, 7 mm wide at tubercula pubertatis; juvenile paratypes 125–135 mm long, 5 mm wide. Segment number: Holotype 249; clitellate paratypes 169–328, regenerating individual 112, abscised 84+. Prostomium: Prolobous, small. Segmentation: Secondary annulation present on preclitellar segments; 1 and 2 short, not clearly separated, both with irregular longitudinal grooves; 3 simple, 4–8 with 2 simple ringlets similar in size and appearance; 9 with 2 irregularly annulated ringlets, second shorter than first; 10 and the following simple. Setae: Moderate in size; on preclitellar segments ab paired distantly, postclitellarly closely paired with ab = cd, aa> bc; first pairs of ab on segment 3. Nephridial pores: First pair in intersegmental furrow 3/4. Female pores: In 14, medially. Male pores: In area of tubercula pubertatis, in intersegmental furrow 14/15, with small swollen lips. Spermathecal pores: Only in intersegmental furrow 12/13, dorso-laterally in clitellar area.

Clitellar region ( Fig. 2 ): Clitellum: Well developed on holotype and paratypes on 12–22, segmented; clearly bordered anteriorly and posteriorly. Ventral borders on 12– 1/n18 parallel with dorsal edges of tubercula pubertatis; on 1/n18–22 extends to ventral lines of tubercula pubertatis. Tubercula pubertatis: Irregular oval, on segments 1/n14– 1/n18, embracing the swellings of male pores; anteriorly narrower, with ventral borders much above b setal lines, posteriorly extending scarcely more latero-medially. Papillae: Small swellings associated with ab setae on 10–12 and 19–22, 23; paired or single.

Internal characters:

Septa: Septa 4/5 very much thickened, muscular, 5/6 6/7 very thin; 7/8 8/9 thickened moderately, both similar in size and appearance; other septa thin, firm. Gizzard: Barrelshaped, in 7; anteriorly muscular, posteriorly soft. Calciferous glands: Dorso-lateral in 9 extending into 10; separated ventrally and dorsally; connected with oesophagus in area of septa 9/10. Intestine: Commences in 12. Typhlosole: Commences abruptly as thick U-shaped tube in 19 or 20; terminates in holotype in segment 144; in complete paratype in 146; in abscised individual extends through all regenerated segments to the last segment 112. Dorsal blood vessel: Double in 5–9; in 5–7 thin adjacent tubes, in 8 moderately enlarged, separated; in 9 cordiform. Single, thin when crossing septa, and single although thicker in 10, and in the following segments. Paired dorsoventral vessels: In 4–7 simple, thin vessels, in 8 slightly enlarged, 9–11 gradually enlarging, moniliform. Nephridia: Meganephridia ; coiled loops with oblong caeca.

Reproductive organs: Spermiductal funnels: Proandric arrangement (in segment 10); one pair of large funnels enclosed in sacs closely connected one with another and with seminal sacs. Vasa deferentia: In holotype not seen, covered by thick tissue of body wall. In paratype observed as single ducts running to anterior part of segment 15, and entering body wall at 14/15, where externally are noticeable male pores. Seminal vesicles: Moderate in size, anteriorly connected with spermiductal funnels at septum 10/11, extending into segment 11. Spermathecae: In only one row, close to septa 12/13; tubular, bent, two at each side; modest quantity of sperm observed in some of spermathecae. Ovaries: Large rosette-like funnels, posteriorly in segment 13, close to median line. Genital glands: Not observed.

Biological notes: Found in the soil of primary grassland conserved in the Vernon Crookes Nature Reserve. The reserve is situated in the southern part of coastal KwaZulu-Natal, surrounded by sugar cane fields and Eucalyptus plantations. This small reserve, comprising patches of indigenous coastal forest, bush clumps and extensive stands of grassland, is a valuable oasis of relict habitats. Close to the type locality of P. crookesi , four other indigenous microchaetids in two other genera were previously collected and described: Tritogenia curta Plisko & Zicsi, 1991 , Microchaetus vernoni Plisko, 1992 , Microchaetus zaloumisi Plisko, 1992 , and Microchaetus ambitus Plisko, 1998 .

Discussion: Closely related to P. warreni (Michaelsen, 1913 a) . Both species have only one row of spermathecal pores in intersegmental furrow 12/13, and thickened septa 4/ 5 7/8 8/9. However, the thickness of septum 4/ 5 in this new species distinguishes it from other species assigned to the P. warreni species-group. The position and shape of the clitellum and tubercula pubertatis also differ.

Figures

Fig. 2. Proandricus crookesi sp. n. Clitellar region, ventral view. [C = clitellum; T= tuberculum pubertatis.]