Parisotoma yehlathi, Janion-Scheepers & Potapov & Deharveng, 2023

Janion-Scheepers, Charlene, Potapov, Mikhail & Deharveng, Louis, 2023, New and little-known Isotominae (Collembola, Isotomidae) from South Africa, Zootaxa 5346 (3), pp. 337-347 : 340-341

Parisotoma yehlathi sp. nov.

Figs 11–20

Material. Holotype female on slide and 22 paratypes (on slide), SAF-107, SAF-109, SAF-116 Africa , South Africa, Somerset West , Helderberg Nature Reserve, 34.0406°S, 18.8735°E, Afromontane forest leaf litter, 04 March 2009, L. Deharveng & A. Bedos leg.

Holotype and 9 paratypes in SAMC (SAF-116), 6 paratypes in MNHN (SAF-107); 4 paratypes in MSPU (Saf- 109).

Additional material. “ RSA 10_JNK030”, Africa, South Africa, Western Cape, Stellenbosch, Jonkershoek Nature Reserve, Swartboskloof Trail , 12 Aug. 2010, 33.99577°S, 18.95252°E, C. Janion; “RSA11_KOG007”, Africa , South Africa, Western Cape, Kogelberg Nature Reserve , 04. Oct. 2011, 34.332130°S, 18.950936°E, C. Janion .

Description. Body length from 0.7 to 0.9 mm. Grey, eye spot black and distinct ( Fig. 16 ). Ant.I with 4 s-chaetae ventro-laterally of which 2 long chaeta-like and 2 short, 3 basal microchaetae, 2 dorsal and 1 ventral ( Fig. 11 ). Inner s-chaetae of AO III rather small. One large ocellus on each side of head ( Fig. 15 ). PAO wide, 1.4–1.7 as long as internal crest of Claw III. Labral formula 4/554, apical folds sharp. Maxillary outer lobe with 4 sublobal hairs and trifurcate apical palp. Labial palp with 5 papillae (A–E) and full set of guards (16, e7 present), lateral process as common. Labium with 4 basomedian, 5 basolateral, and 4 proximal chaetae. Number of postlabial chaetae 3+3. Maxillary head unmodified: both lamellae 1 and 6 with two rows of filaments ( Fig. 20 ). Lower subcoxa of leg I with one outer chaeta ( Fig. 13 ). Tibiotarsi of all legs with only 7 chaetae in apical whorl. Claw without clear internal teeth, with two minute lateral teeth. Empodial appendage with broad lamella. Ventral tube with 2+2 lateral, 3+3 anterior, and 4–5 posterior chaetae ( Fig. 14 ). Retinaculum with 4+4 teeth and 2 chaetae. Furcal subcoxa with 24–27 chaetae. Manubrial thickening simple. Anterior side of manubrium as common. Dens with numerous chaetae on anterior side and 8 chaetae on posterior side (2 basal, 3 median and 3 lateral) ( Figs 18, 19 ). Mucro with 3 teeth.

Axial chaetotaxy for Th.II, III normally with 11–12+11–12, 9–10+9–10 chaetae. Macrochaetae differentiated, ciliate, on last abdominal segments with ca 15 cilia ( Fig. 17 ), on Abd.V longer than length of tergite (as 1: 1.6–1.9). On Th.II–Abd.V, s-chaetae thin, well different from common chaetae, sensillary chaetotaxy as: 2 al+5 accp, 1 al+5 accp / 5 accp, 5 accp, 5 accp, 1 am+5 accp, 2 am+5 accp ( Figs 12, 13 ). From Th.II to Abd.III, s-chaetae accp5 missing on each side of segment, and on Abd.IV one s-chaeta (accp4) missing. On Th.II–Abd.III, ms-chaetae as: 1,1/1,0,1. On Abd.III ms-chaetae large, as long as s-chaetae ( Fig. 12 ). Number of common chaetae in p-row between s-chaetae and ms-chaetae: 3s1s1s1s3s (Abd.I), 2s1s1s1s2–3s (Abd.II), 2–3s1s1s1s1ms1s (Abd.III), 1s1s1s1(s)1s (Abd.IV) ( Figs 12, 13 ). Males present.

Distribution. Currently known from several fragmented Afromontane forest localities in the Western Cape.

Remarks. The species is well defined by moderately reduced sensillar chaetotaxy: 5 s-chaetae (vs 6) in p-row on Abd.I–III. The most South African species show complete (6 s) or more reduced (4 s: P. sexsetosa , P. ruseki sp. nov.) set of s-chaetae. It is also characterized by the presence of 8 chaetae on posterior side of dens, that is unknown among “austral” representatives of the genus so far.

Name derivation. The word “yehlathi” means “of the forest” in the local language, isiXhosa. It reflects the occurrence of this species in Afromontane forests in the Western Cape of South Africa.

Figures

FIGURES 11–20. Parisotoma yehlathi sp. nov.: 11, s and bms on Ant.I; 12–13, s- and ms-chaetae on Abd. III–V (12) and Th.II–Abd.II (13); 14, ventral tube, lateral view; 15–16, ommatidia and PAO, without (15) and with (16) pigmentation; 17, macrochaeta on Abd.V; 18–19, dens, posterior (18) and lateral (19) views; 20, maxillary head with more detailed lamellae 1 and 6. Abbreviations as on Figs 1–10.