Proandricus oresbiosus, Plisko, 2003

Plisko, Jadwiga Danuta, 2003, Eleven new South African earthworms (Oligochaeta: Microchaetidae) with new information on some known species, and an inventory of the microchaetids of KwaZulu-Natal, African Invertebrates 44 (2), pp. 279-325 : 299-301

Proandricus oresbiosus sp. n.

( Figs 10–11 )

Etymology: G. oresbios = living in or on mountains. The species name refers to the type locality situated in the Drakensberg mountain range.

Material examined: KwaZulu­Natal: Holotype NMSA / Olig.02440, Drakensberg, Royal Natal National Park, north side of Devil’s Hoek River (28º41'S: 28º53'E) grassland, under rock, 4 December 1996. Paratypes: NMSA / Olig.02434 ca. 28 km north­west of Bergville (28º42'S: 29º22'E) primary grassland, between roots of various plants, from sandy moist soil, 5 December 1996, 3 cl + 1 juv. All collected by JDP and TL .

Description based on holotype and paratypes.

External characters:

General: body cylindrical. Colour: in life and alcohol­preserved, grey, not pigmented. Dimensions: preserved and slightly contracted holotype 90 mm long, 4,5 mm wide at 10, 6 mm at tubercula pubertatis; clitellate paratypes 75–102 mm long. Segment number: holotype 106, paratypes 117–138; juvenile 120. Prostomium: prolobous. Segmentation: secondary annulation present on preclitellar segments; 1 and 2 simple, with irregular longitudinal grooves; 3 simple; 4–6 with two simple ringlets similar in size and appearance; 7–9 with two ringlets, second shorter than first; 10, 11, clitellar and postclitellar simple. Setae: minute, closely paired in regular rows, although ab setae on some segments are slightly shifted medially; first pairs on 3. Nephridial pores: obvious in cd setal lines; first pair in intersegmental furrow 2/3. Female pores: not observed. Male pores: probably in intersegmental furrow 16/17. Spermathecal pores: externally not observed.

Clitellar region ( Figs.10–11 ): Clitellum: saddle­shaped, segmented, white; on 1/n11,12– 20,21; ventral edges extend slightly below cd setae. Tubercula pubertatis: glandular oval pads; segmented, rimmed dorsally and ventrally; on 1/n16,17–20, dorsally bordering clitellum at cd setae. Papillae: glandular, moderate in size, paired, encircling ab setae on segments 10–12; on holotype additionally on 16 small blisters ( Fig. 10 ); on two paratypes a pair of prominent, yellowish papillae on 18 ( Fig. 11 ).

Internal characters:

Septa: 4/5 7/8 8/9 thickened moderately, slightly muscular, firm; 5/6 6/7 not thickened, although strong. Gizzard: globular, muscular, in 7. Calciferous glands: in 9, large, distinctly separated dorsally and ventrally. Intestine: commences in 12. Typhlosole: commences in 22, terminates in paratype in 56. Dorsal blood vessel: 5–8 partly separated, partly double; 9 enlarged, double, cordiform; in 10 and following segments enlarged, simple; crossing septa simple. Paired dorsoventral vessels: 5–8 thin vessels, 9–11 enlarged, moniliform. Nephridia: meganephridia ; coiled loops with elongated caeca. Spermiductal funnels: proandric arrangement; one pair, free in 10. Vasa deferentia : single ducts commence at lateral parts of spermiductal funnels and run backwards at each side of body to posterior part of 16, where enter body wall, and probably into male pores. Seminal vesicles: one pair of large sacs in 11, commencing at septum 10/11. Spermathecae: in 9 and 10; different in size and shape; small ampullae with elongated necks on glandular basis, or simple, elongated ampullae. In 9 two pairs, located in unusual arrangement, i.e. in anterior and posterior parts of segment; anterior pair small, with its ectal ends entering body wall between ringlets of segment 9, with no confirmed connection with spermathecal pores; ectal parts of posterior pair located behind anterior pair, enter into intersegmental furrow 9/10. In segment 10 one pair with ectal parts entering into intersegmental furrow 10/11. No iridescence in spermathecae of both segments was observed; thick, white, mucus was found in three dissected thecae. Ovaries: not observed. Genital glands: in holotype large, flat glands in 10, 12, 16; in paratype one pair of large, composite, round, flat glands in segment 18, associated with papillae of same segment.

Biological notes: The Royal Natal National Park, situated in the central Drakensberg mountain range, between altitude ranges from 1340–3048 m, has different geological formations and several habitat types ( Pooley and Player 1995). The vegetation comprises grassland with short grasses and herbs, ferns, lichens and mosses, stream and riverbank woodland, sage­wood scrub, Protea savannah, bushes, and Podocarpus ­ dominated forests. A large part of the park has been under protection for nearly 50 years. The holotype was collected at the eastern side of the park, in a broad valley, covered with rocks, riverine bush and tall grasses. The paratypes were found outside the park nearly 28 km from the holotype locality, in primary grassland at much lower altitude.

Discussion: The locations of spermathecae in segments 9 and 10 suggest assignation to the lesothoensis species­group. Similar to sani and to amphius sp. n., having spermathecal ectal parts entering intra­segmental body wall. The presence of two distinct pairs of spermathecae in segment 9 distinguishes oresbiosus from other species of this group.

Distribution: Known from Drakensberg escarpment of western KZN ( Fig. 7 ).

Figures

Figs 10–11. Proandricus oresbiosus sp. n. 10. Holotype, ventral view with clitellum, tubercula pubertatis and papilla of segment 16. 11. Paratype, ventral view with clitellum and papillae of segment 18. [C= clitellum, T = tuberculum pubertatis, P = papilla].

Fig. 7. The distribution of Proandricus species in KZN. 1 = adami; 2 = adriani; 3 = alatus; 4 = amphius; 5 = armstrongi; 6 = babanango; 7 = beddardi; 8 = bergvillensis; 9 = bourquini; 10 = bulwerensis; 11 = colletti; 12 = crookesi; 13 = entumeni; 14 = gracilis; 15 = hedothecus; 16 = hlatikulu; 17 = injasuti; 18 = ivari; 19 = jasoni; 20 = lovuus; 21 = marleyi; 22 = martensi; 23 = michelleae; 24 = modestus; 25 = oresbiosus; 26 = ortyi; 27 = pajori; 28 = richerti; 29 = setosus; 30 = thornvillensis.