Chilota quindecimus Pickford, 1937

Plisko, Jadwiga Danuta, 2007, New species of South African acanthodriline earthworms of the genera Eodriloides and Chilota, with a redescription of Chilota quindecimus (Oligochaeta: Acanthodrilidae), African Invertebrates 48 (2), pp. 33-40 : 38-40

Chilota quindecimus Pickford, 1937

Figs 6, 7

Chilota quindecimus: Pickford 1937: 526–528 .

The original species description was based on one immature specimen. Recent collections of sexually developed material allow me to add more data on the species’ morphology, as well as its distribution.

Diagnosis: Clitellum saddle-shaped on 13–16,1/n17. Prostatic pores on slightly swollen tissues. Salivary glands extending backwards beyond septum 4/5. Gizzard in 5, reduced to narrow, soft tube. Intestine begins in 15. Spermatheca ovoid, irregularly folded with short duct; diverticulum unilobate, sessile, overhanging union between spermatheca and duct. Two pairs of prostates; each pair confined to one segment, in 17 and 19.

Description:

External features: Body cylindrical. Colour: colouring and pigmentation of the new alcohol-preserved material differ slightly from the holotype and its original description, given as ‘unpigmented’. New material kept in 75% alcohol for over three years is dorsally violet on 1–12 and last 7 segments; on 1–6, pigmentation extends to b setal lines, on 7– 8 to c, on 9–12 to a; ventrally yellowish white. Dimensions: holotype 43 mm long, new material 43–52 mm long, 2–3 mm wide. Segment number: holotype 96, new material 82–99. Prostomium: tanylobous, with wide, obvious sutures. Setae: arrangement of setae in accordance with original description, widely paired, postclitellarly aa> ab, aa> bc, ab <cd, bc nearly equal to cd. Dorsal pores: absent. Nephridial pores: in original description indicated as being in the c setal lines; due to dissection of holotype the condition cannot be confirmed; on new material not observed externally. Spermathecal pores: ventrolaterally, two pairs, each between b–c, close to intersegmental furrow 7/8 and 8/9, respectively, each encircled by narrow elliptical mark. Female pores: paired, in 14 between aa setae, separated by about one third of aa space. Clitellum : specified by Pickford as circular on 13–16; it is difficult to confirm ventral clitellar tissues on holotype; on new material clitellum clearly saddle-shaped; dorsally overlapping part of segment 17; on 13 extending to ab setae; on 14–16 slightly below ab; anterior clitellar borders obvious, posterior borders faint. Prostatic pores: two pairs not approximated towards the mid-ventral line, on 17 and 19, respectively; in holotype on moderate papillae, on new material on swollen tissues. Male pores: paired, in 18, small openings lateral to b setae. Seminal grooves: very faint, curved furrows. Papillae: not observed on type material; minute, oval disks on segments 8–10 between aa setae on new material. Internal characters: Salivary glands: extend backwards beyond septum 4/5, covering dorsally large anterior part of gizzard. Gizzard: in holotype and in new material reduced to narrow, cylindrical, soft tube. Septa: all thin; although some variations in thickness of septa observed, the most thickened usually 12/13. Intestine: commences abruptly in 15, preceded by enlarged, muscular region of oesophagus in segments 12–13, followed in segment 14 as constricted, much narrower part forming valves. Typhlosole: absent. Lateral hearts: last pair in 12, slightly enlarged. Nephridia : meganephridia; elongated, thin, with small terminal vesicles. Ovaries: in 13, small. Testes and male funnels: proandric arrangement; male funnels large, medially in segment 10, free, iridescent. Vasa deferentia : medially, run to 17 where they enter body wall and extend to small openings in 18. Seminal vesicles: two pairs, in 9 and 11; anterior pair large, commencing from ventral part of septum 9/10 as lobulate sacs extending dorsally, occupying large part of segment 9. Posterior pair commencing from septum 10/11, much smaller than anterior, lobulate, extending dorsally in 11. Spermathecae: two pairs, in 8 and 9; shapes of spermathecae in new material differ from those described and illustrated by Pickford (1937), but are similar to spermathecae observed and photographed in the holotype ( Fig. 6 ) and new material ( Fig. 7 ). Duct wide, bent, extending into moderate, ovoid ampulla; diverticulum unilobate, nearly as large as ampulla, sessile, connected at duct/ ampulla union. Spermathecal ectal ducts enter body wall near septa 7/8 and 8/9, respectively. Iridescent sperm present in diverticula. Prostates: two pairs, in 17 and 19. Duct originates as delicate, short, thin tube; prostatic gland tubular, slightly folded, extending dorsolaterally. Each tubular gland together with prostatic duct confined to only one segment. Penial setal retractor muscles: commence at septa 17/18 and 18/19, respectively; thin, strong. Penial setae: a and b alike; stem slender, almost straight,

curved at nearly half of its length; smooth, unornamented; distally slightly curved and pointed, smooth.

Holotype (examined): SAM A21680 ( SAMC), 1 cl broken into three pieces. KwaZulu-Natal: Kranskop , xi.1917, K.H. Barnard.

New material examined: KwaZulu-Natal: NMSA /Olig.03719, 1 cl, and NMSA /Olig.03814, 2 mature with less developed cl, Swartkop Forest (29°35'36.267''S: 30°15'10.878''E) from rotten log on forest floor, between dense herbaceous roots, 22.i.2003. NMSA / Olig. 03723 1 cl & 1 juv, Swartkop Forest (29°35'36.402''S: 30°15'11.071''E), in rotting trunk lying between thick undergrowth and shrubs; all collected by A.J.Armstrong, L. Mnguni, G. Dittrich.

Distribution: Pickford (1937) described this species from ‘Kranzkop, Natal’, which probably refers to the area at or near the town of Kranskop (28°58'S: 30°50'E), or its close neighbourhood, in the Midlands of KZN. New material was collected south-west of the type locality.

Figures

Figs 6, 7. Chilota quindecimus, spermathecae, 400×: (6) holotype; (7) new material. Abbreviations: A – ampulla, U – unilobate diverticulum.