Proandricus bongani, Nxele, 2023

Nxele, Thembeka C., 2023, A new species of Proandricus Plisko, 1992 (Clitellata, Microchaetidae) from a South African grassland, Zootaxa 5255 (1), pp. 18-22 : 19-21

Proandricus bongani sp. n. ( Figure 1 and 2 )

Locality and material. South Africa: KwaZulu-Natal: Drummond, 29°44’42.2’’S; 30°41’27.3’’E, 683 m, 18.iii.2021, T. Nxele, B. Bambalele leg. Holotype. One clitellate, NMSA-Olig .29834 .

Paratypes. Six clitellate, NMSA-Olig .29835 .

Additional material. Four juveniles NMSA-Olig .29836 .

Description. External. Holotype: Body length 138 mm, width 7 mm at tubercula. Segment number 218. Paratypes: 96–126 mm in length, one abscised, width 7–8 mm. Segment number 194–236. Colour whitish grey. Prostomium prolobous. Segments with different secondary annulation, preclitellar segments: segment 1–3 simple with longitudinal grooves, 3 with less grooves on the holotype or grooves missing on some paratypes; 4–6 with two annuli per segment of similar size and appearance; 7 with two annuli which have superficial divisions; 8 and 9 with two annuli, the posterior smaller than the anterior, in some paratypes the annuli have additional superficial divisions; 10 and clitellar region simple; segments after clitellum randomly annulated. Setae visible from segment 3, distantly paired on preclitellar segments, closely paired after clitellum, on segment 10, aa: ab: bc: cd: dd = 20:4:25:2:85. Male pores not observed. Female pores in 14. Spermathecal pores in a row in 12/13 intersegmental furrow, 5 in holotype and range from 3–5 on paratypes. Clitellum saddle shaped on 12–21, with clear borders, segmented, the anterior and posterior ventral borders are between b and c setal lines. Tubercula pubertatis on 15,16–18, anterior with no distinct separation from clitellum. Genital papillae between 9–23, slightly raised on ab setae.

Internal. Septa 4/5 muscular, 7/8, 8/9 moderately thickened. Other septa thin. Gizzard well developed in 7, muscular anteriorly, soft in posterior region. Calciferous glands in 9–10, separated dorsally and ventrally, lobed, septum 9/ 10 in the middle of the gland, lobes are different in holotype and paratypes. Intestinal origin in 12. Typhlosole commences in segment 20 and terminates in segment 115 in holotype. Dorsal blood vessel double in 7– 9, separated; in 9 forming cordiform shape, simple when crossing septa. Holonephridia, one pair per segment with V-shaped bladders with coiled loops. Proandric. Seminal vesicles in 10, 11, reduction in the anterior pair is observed and is more on the ventral side, the pair in 11 is large. Spermathecae in a row, only in 12 near 12/13 intersegmental furrow, more than one pair per segment, different numbers per side ranging from 2 to 5. Genital glands absent.

Etymology: This species is named in honour of Bongani Bambalele for his continuous help during fieldwork.

Remarks: This species is similar to species in the Proandricus warreni species group ( Proandricus londti Plisko, 1993 , warreni ( Michaelsen, 1913) , zicsi Plisko, 1993 and crookesi Plisko, 2002 ). These species have three thickened septa: 4/5, 7/8 and 8/9, as well as spermathecae in one segment. However, the new species differs from all in the position of the clitellum, position and shape of calciferous glands and the number and shape of spermathecae ( Figure 2 ). Species in this species group have varying pairs of spermathecae, ranging from two to five pairs in one segment. The occurrence of spermathecae in one segment is observed in two other species in the Microchaetidae ( Geogenia pondoana ( Michaelsen 1913) and Geogenia zaloumisi ( Plisko 1992)) as well as in five species in the Tritogeniidae ( Tritogenia benhami (Michaelsen) , T. kruegeri Plisko & Zicsi , T. grisea (Michaelsen) , T. monosticha Plisko and T. ngomensis Plisko ). The typhlosole in bongani starts differently in different specimens, in some it starts as a flat tube while in others it is a thick, almost round tube.

Proandricus species occur mainly in natural habitats with minimum or no disturbance ( Plisko 2002), this is true for most indigenous species. Most Proandricus species have been collected in grasslands and are known from single records ( Figure 3 ), they are possibly less tolerant to disturbance ( Plisko 1993, 2002). A recent assessment of the usefulness of parks in preserving native earthworms in Brazil found native earthworms in three parks ( Ferreira et al. 2018) and this shows that native species may occur in spaces that are open to the public. Proandricus bongani was collected together with Tritogenia species and this shows that the grassland has not been subjected to extreme human disturbance or perhaps the tolerance of these taxa to disturbance has been underestimated. Proandricus crookesi and bongani have been collected from KwaZulu-Natal and each is known only from their type localities; zicsi is also known from the type locality in the Eastern Cape; londti is known from two locations in Gauteng and in Lesotho. Proandricus warreni is known from KwaZulu-Natal, Eastern Cape and Free State. The wider geographical distribution of warreni may indicate better adaptation to wider environmental conditions.

Figures

FIGURE 1. Calciferous gland with septum 9/10 in the middle of the gland. Scale bar 1 mm.

FIGURE 2. Spermathecae of warreni (A) and bongani (B).

FIGURE 3. Distribution of species in the P. warreni species group.