Proandricus notabilis, 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 : 109-110

Proandricus notabilis sp. n.

Fig. 5

Etymology: L. notabilis (noteworthy, distinguished). Refers to the unusual position of spermathecae.

Description:

External features: Body cylindrical. Preserved in alcohol dorsally brownish-grey, ventrally grey.Abnormally extended during preservation, internally slightly decomposed. Holotype 360 mm long, 8 mm wide at 10, and 8 mm at tubercula pubertatis. Segment number: holotype 376. Prostomium: prolobous, small. Segmentation: secondary annulation present on preclitellar segments; 1 and 2 simple, with irregular longitudinal grooves; 3 simple; 4–9 with two simple ringlets, posterior shorter than anterior; 10 and 11 simple, clitellar segments simple, similar in size, postclitellar simple, randomly annulated. Setae: minute, closely paired in four regular rows. Nephridial pores: conspicuous, in front of cd setae. Female pores: not observed, probably in 14 laterally, where there are slight marks. Male pores: in 14/15, in front of tubercula pubertatis. Spermathecal pores: obvious in intersegmental furrows 10/11, 11/12 and 12/13. Papillae: not observed.

Clitellar region ( Fig. 5 ): Clitellum: saddle-shaped, segmented, white, on 1/n11, 12–1/n22; anterior and posterior borders not clearly marked; clitellar tissues extending partially on 11 and 22 respectively, and covering only dorsal parts of the segments; laterally extends to tubercula borders. Tubercula pubertatis: well developed, elongated strips, on 1/n15–18, between cd–ab setae, with shallow grooves separating each strip from clitellar tissues.

Internal characters: Septa: 4/5 heavily thickened, muscular, extending to nearly half of segment 5; 5/6 and 6/7 not thickened; 7/8 and 8/9 thickened much less than 4/5, muscular; other septa thin, firm. Gizzard: in 7, globular, muscular. Calciferous glands: in 9, attached laterally with oesophagus; distinctly separated dorsally and ventrally. Intestine: commences in 13. Typhlosole: commences possibly in 20, terminates in holotype in 165. Dorsal blood vessel: 4–7 simple; 8 double, separated; 9 enlarged, double, cordiform; in 10 and following segments enlarged, simple; simple when crossing septa. Paired dorsoventral vessels: 5–8 thin, 9–11 enlarged, moniliform. Nephridia : due to poor specimen preservation, precise shape and position of excretory organs were not established; decomposed parts of holonephridia were observed in anterior segments. 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: not observed due to decomposed tissues. Seminal vesicles: one pair of irregularly shaped sacs, commencing at septum 10/11, extending into 11. Spermathecae: in segments 10, 11, 12; anterior pair very small, globular, deeply embedded in wall tissue; ectal parts entering in intersegmental furrow 10/11. Second pair slightly larger than anterior; elongated thecae with ectal parts in intersegmental furrow 11/12. Posterior pair in 12; large, elongated club-shaped, with ectal parts entering in 12/13. Iridescence observed only in posterior pair. Ovaries: not observed. Genital glands: not observed.

Comparison and comments: This species is unique among all known congeners, having three pairs of spermathecae in segments 10, 11 and 12, with spermathecal pores in intersegmental furrows 10/11, 11/12, 12/13. The spermathecal pores occurring in these intersegmental furrows characterise no other proandric species. Until now such position of the spermathecal pores has been noted only in holandric microchaetids of genera Tritogenia and Michalakus (Table 1).

Holotype: clitellate NMSA /Olig.03620: KwaZulu-Natal: Phinda (27.77751ºS: 32.3107ºE), 16.iii.2004, M. Hamer (Earthwatch Team 6, 2457).

Paratype: NMSA /Olig.03913, 1 cl, collected with holotype .

Biological notes and distribution: This species was found together with Microchaetus natalensis ( Kinberg, 1867) , Tritogenia phinda sp. n., and juvenile specimens of Proandricus sp. It is known only from one locality in northern KwaZulu-Natal.

Figures

Figs 5–8. (5) Proandricus notabilis sp. n., holotype, lateral part of clitellum and tuberculum pubertatis, 60 X; (6, 7) Proandricus zeugosus sp. n., holotype: (6) anterior part of body, laterally, 60 X, (7) spermathecae of segment 12, 140 X; (8) Tritogenia phinda sp. n. holotype, clitellar region, ventral view, 60 X. Abbreviations: C–clitellum, T–tuberculum pubertatis, P–papilla of segment 25, Sp–spermathecae.