Proandricus holbeck, Plisko, 2005

Plisko, Jadwiga Danuta, 2005, Five new South African earthworm species of the family Microchaetidae (Oligochaeta) with exceptional anatomical features, African Invertebrates 46, pp. 103-113 : 107-108

Proandricus holbeck sp. n.

Figs 3, 4 Etymology: Named after Holbeck , the type locality area.

Description:

External features: Body cylindrical. Preserved in alcohol yellowish-grey, not pigmented. Holotype, being probably abscised posteriorly when collected, 117 mm long, 4 mm wide at 10 and 8 mm at tubercula pubertatis; paratype 115 mm long. Segment number: holotype 214+; paratype, with posterior part regenerated at earlier state, 145. Prostomium: prolobous, small. Segmentation: secondary annulation present on preclitellar segments; 1 and 2 simple, with irregular longitudinal grooves; 3 simple; 4–8 with two simple ringlets, similar in size and appearance, 9 with two ringlets, posterior shorter than anterior; 10, 11 and clitellar segments simple, similar in size; postclitellar randomly annulated. Setae: minute, closely paired in regular rows; aa> bc. Nephridial pores: conspicuous, in front cd setae; first pair in intersegmental furrow 2/3. Female pores: in 14 between b–c setae, closer to b. Male pores: in 17/18, in tubercula pubertatis. Spermathecal pores: obvious; one pair in intersegmental furrow 12/13; two pairs in 13/14. Papillae: on 19 and 20, paired, large, yellowish, linked with genital glands.

Clitellar region ( Fig. 3 ): Clitellum: saddle-shaped, segmented, white, on 13–24; anterior and posterior border well marked; laterally clitellar tissues extending to ab setae. Tubercula pubertatis: rectangular pads with rounded corners, segmented; on 17–20, proceeding between cd and ab setal lines, covering only partially segment 16 at intersegmental furrow 16/17; clearly separated from clitellar tissues by narrow grooves.

Internal characters: Septa: 4/5–6/7 not thickened; 7/8 and 8/9 strongly thickened, muscular; other septa thin, soft. Gizzard: in 7, globular; soft at septum 6/7, muscular when terminating at 7/8. Calciferous glands: in 9, globular, distinctly separated dorsally, ventrally with narrow groove. Intestine: commences in 13. Typhlosole: exact commencement was not established due to much softened tissues; possibly in 18; terminates in holotype behind 214; in paratype, having 145 segments, terminates in 143; presence of typhlosole in segment preceding last segment may be indicative of specimen regeneration. Dorsal blood vessel: 5–6 double, separated; in 7 double, separated in posterior part, 8 double, widely separated; 9 enlarged, double, cordiform; simple when crossing septa; in 10 and following segments, enlarged, simple. Paired dorsoventral vessels: 5–8 thin, 9–11 enlarged, moniliform. Nephridia : bushy coiled loops, with extended V-shaped, much elongated caeca. Male funnels: proandric arrangement; one pair of large, iridescent funnels, enclosed in sac closely connected posteriorly at septum 10/11 with seminal sacs. Vasa deferentia: single tubes extending to intersegmental furrow 17/18, where entering body wall and male pores. Seminal vesicles: one pair, heavily swollen sacs, commencing at septum 10/11, extending into 11. Spermathecae: in segments 12 and 13, variable size, dark-grey; anterior pair very small, globular, deeply embedded in wall tissue, with ectal parts at 12/13; in segment 13 two pairs, larger than anterior, elongated, curved, with ectal parts in intersegmental furrow 13/14. Iridescence not observed in any spermathecae. Ovaries: not observable due to internal decomposition of this part of body. Genital glands ( Fig. 4 ): one pair in 19; each composed of two J-shaped, elongated sausage-like glands, and two slightly shorter and thinner fingershaped; all linked with external papillae.

Comparison and comments: This proandric species with spermathecal pores in intersegmental furrows 12/13 and 13/14, male pores in 17/18, and with only two thickened septa 7/8 and 8/9, is unique among known congeners. In other proandric species with spermathecal pores located in 12/13 and 13/14, constituting the marenzelleri species-group (Plisko 2005), the male pores occur in intersegmental furrow 15/16, and three septa are thickened.

Holotype: clitellate, NMSA /Olig.03911: KwaZulu-Natal: Karkloof [range], Holbeck area, Mbona [Estate] (29.30087ºS: 30.35948ºE), alt.approx. 1300 m, shrubby grassland, on path after rain, 19.iv.2004, D.G. Herbert. Middle part of the body partially extended during preservation, internally slightly decomposed.

Paratype: NMSA /Olig.03912, 1 cl, collected with holotype .

Biological notes and distribution: This species was found in shrubby grassland situated between stands of indigenous mistbelt forest characteristic of the Midlands in KwaZuluNatal. It was collected close to the range of the microchaetid Tritogenia lunata Plisko, 1997 .

Figures

Figs 3, 4. Proandricus holbeck sp. n., paratype: (3) clitellar region, ventral view, showing tubercula pubertatis and papilla of segment 19, 60 X; (4) ventral view showing genital gland and spermathecae, 120 X. Abbreviations: P–papilla, T–tuberculum pubertatis, Gg–genital gland, Sp–spermatheca of segment 13.