Udeina mapelane, Plisko, 2004

Plisko, Jadwiga Danuta, 2004, Review of the balantine genus Udeina Michaelsen, 1910 with descriptions of six new species in South Africa (Oligochaeta: Acanthodrilidae, Acanthodrilinae), African Invertebrates 45 (1998), pp. 287-287 : 300-302

Udeina mapelane sp. n.

Figs 7–9

Etymology: Named after the type locality Mapelane Nature Reserve, an African place name in apposition.

Type material: Holotype: clitellate NMSA /Olig.03881 KwaZulu­Natal: Mapelane Nature Reserve (28 26'S: 32 24'E) coastal forest, at forest outskirts, sandy soil with thick layer of black topsoil, 14 May 1997, JDP . Paratypes: collected together with holotype NMSA /Olig.03882, 9 cl; NMSA /Olig.02563, 6 cl + 23 juv; Grid 5, NMSA / Olig.02561, 2 specimens with brown cl + 3 juv; Grid 3 NMSA /Olig.02562, 3 cl + 11 juv. Other material: Mapelane Nature Reserve , forest disturbed for more than 30 years, material collected by workers of Pretoria Mammals Research Institute , in pitfall traps below surface layer, 26 August 1996: Grid 1, NMSA /Olig.02522, 1 cl; Grid 2, NMSA /Olig.02523, 8 cl; Grid 3, NMSA /Olig.02525, 1 clitellate + 1 juv; 26–30 August 1996, Grid 5, NMSA /Olig.02517, 1 cl & NMSA /Olig.02526, 1 cl. Mapelane Nature Reserve, indigenous coastal forest (Zulti­North) undisturbed for over 37 years, 26–27 August 1996: Grid 1, NMSA /Olig.02502, 1 cl & NMSA / Olig.02507, 1 cl; Grid 5 in pitfall traps located in litter, NMSA /Olig.02506, 6 cl + 2 juv & NMSA /Olig.02508, 1 cl .

Additionally, 12 samples of this species collected also in the Mapelane Nature Reserve by workers of the Mammal Research Institute were examined, but due to their poor preservation were not taken into the Natal Museum collection.

Description:

External features:

Body cylindrical, in life dorsally dark violet, iridescent; alcohol­preserved dorsally violet, anteriorly extending pigmentation to c setal lines, posteriorly to d setae; ventrally yellowish­grey. Dimension: holotype 120 mm long, 5 mm wide; mature specimens 89–123 mm long, 4–6mm wide. Segment number: holotype 165; paratypes 120–174. Prostomium:tanylobous, narrow, with well­marked sutures. Setae: widely paired, aa> bc; ab <bc; ab <cd; Dorsal pores: not observed. Nephridial pores: not observed. Spermathecal pores: in intersegmental furrow 7/8, in front of b setae, in small swellings. Female pores: paired, in 14, posteriorly to b setae. Clitellum : saddle­shaped, with thick layer of yellow­white tissues on 13–17; on mature individuals distinctly marked anteriorly and posteriorly; on some mature individuals marked by brownish colouration, with no clitellar tissues externally. Prostatic pores: one pair close to b setae, on papillae in segment 17. Male pores: medially to b setae, in ecliptic depressions in segment 18. Seminal grooves ( Fig.7): deep, straight furrows between prostatic and male pores, widened at connection with male pores. Papillae: small rounded swellings on 14, 15, 16 encircling a setae.

Internal characters:

Salivary glands: large, extending backward beyond septum 4/5, covering large part of gizzard. Gizzard: well developed, in segment 5, cylindrical, muscular. Septa: 6/7– 11/12 increasing in thickness, 12/13–15/16 decreasing. Intestine: commences in 16. Lateral hearts: last pair of hearts in 12. Nephridia: moderate loops without terminal vesicles. Ovaries: large, cluster­shaped, in 13. Testes and spermiductal funnels: spermiductal funnels large, free, ventrally in segment 10. Vasa deferentia : well developed; at each side of the body a single duct commences in segment 10 and runs backward, entering male pore in segment 18. Seminal vesicles: two pairs; in 9 and 11; both pairs lobular, anterior smaller then posterior. Spermathecae ( Fig. 8): in segment 8. Ampulla large, ovoid. Duct nearly as long as ampulla, entering body wall in intersegmental furrow 7/8. Diverticulum unilobate, globular, iridescent, attached laterally to duct below joint ampulla/duct. Prostates ( Fig. 9): one pair in segments 17–23. Prostatic gland multi­folded, looped, passing irregularly backwards through segments 18–23; thin septa of occupied segments partly pierced by looped prostatic gland. Prostatic duct connected with prostatic gland by thin, soft tube at posterior part of segment 17, becomes elongated, looped, and thick where enters prostatic pores in segment 17. Penial setae: a and b well developed, supported by muscles of segments 16/17. Penial setal retractor muscles: commence at septum 16/17.

Biological notes and distribution: Mapelane Nature Reserve is located in coastal southern Zululand, south of Lake St. Lucia estuary, on the south bank and at the mouth of the Mfolozi River. The dense coastal dune forest extends nearly 9 km southwards from the river mouth and separates the inland floodplain and the sea. Much of the indigenous forest with unique vegetation has been under protection for over 100 years. The adjacent forested area not falling under protection, but also retaining some indigenous trees and bushes, has been used for wood production, although soil and litter were not much devastated. In August 1996, staff of the Mammal Research Institute, University of Pretoria, compared collections of litter and soil­fauna from disturbed and pristine areas. The earthworms were caught in pitfall traps placed in the litter and in the first layer of the topsoil. The new species U. mapelane was collected in both forested parts, but more were trapped in the less disturbed area. A similar earthworm collection was obtained in May 1997 by digging in undisturbed parts of the indigenous forest. An abundant population of U. mapelane was observed in the soil and litter. It is noteworthy that within Udeina this is the only species found in such large numbers, suggesting that it prefers organically rich, undisturbed soils.

The species was collected in May and August, locally the beginning and middle of the winter; a mild climate is characteristic of the coastal area. Abundant occurrence of fully matured individuals, juveniles, and specimens in post sexual­states at the time of collecting suggests activity during the whole year.

Discussion: This species, having prostatic pores in segment 17, male pores in 18, commencing intestine in 16, and having the last pair of hearts in 12, is closely related to U. pliskoae . They differ in two substantial characters. Spermiductal funnels are enclosed in U. pliskoae , but they are free in U. mapelane . The size and shape of the whole spermatheca differ. In U. mapelane the length of the spermathecal duct is much longer than in U. pliskoae .