Folsomotoma amyliuae, 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 : 341-344

Folsomotoma amyliuae sp. nov.

Figs 21–33

Type material. Holotype male on slide and 10 paratypes. South Africa, KwaZulu-Natal, Forest leaf litter, Tullgren extraction, 24 Jan 2019, near Premier Resort Sani Pass, leg. C. Janion-Scheepers. Holotype and 3 paratypes in SAMC, 3 paratypes in MNHN; 3 paratypes in MSPU.

Description. Body length of adults 0.8–1.0 mm. White, with scattered pigment grains on corpus, eye spot darker ( Fig. 26 ). Ant.I with 4 s-chaetae ventro-laterally (2 long and thick and 2 very short), and 3–4 basal microchaetae ( Fig. 23 ). S-chaetae on Ant.IV thin. One small ocellus, PAO wide ( Fig. 21 ) 1.4 to 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 16 guards (e7 present). Labium with 4 basomedian, 5 basolateral, and 4 proximal chaetae. Invariably 4+4 postlabial chaetae, one pair smaller, as in Parisotoma ekmani ( Fjellberg, 1977) ( Fig. 30 ). Maxillary head unmodified. Lower subcoxa of Leg I with one outer chaeta. Tibiotarsi of all legs with only 7 chaetae in apical whorl. Claw with small lateral teeth and without internal tooth ( Fig. 29 ). Ventral tube with 4+4 latero-distal, 3+3 anterior, and usually 3 posterior chaetae ( Fig. 28 ). Retinaculum with 4+4 teeth and 2 chaetae. Furcal subcoxa with 18–23 chaetae. Manubrial thickening not simple, with few teeth ( Fig. 31 ). Anterior side of manubrium with median 3+3 spines at edge, 3+3 distal long chaetae and 18–20 chaetae on main part ( Fig. 32 ). Dens with numerous chaetae on anterior side and 8 long chaetae on posterior side (2 basal, 3 median and 3 lateral), without spines although few inner chaetae thickened ( Fig. 32 ). Mucro with 3 teeth.

Axial chaetotaxy for Th.II, III, Abd.I, II ~12+12, 9–11+9–11, 3+3, 3+3. Glands of chaetae not seen. Macrochaetae of middle size, ciliate, on Abd.V longer than length of tergite (as 1.6–1.9: 1) ( Figs 22 , 27 ). On Th.II–Abd.V, s-chaetae well shorter than common chaetae, sensillar chaetotaxy ( Figs 24, 25 ) as: 2al+3accp, 1al+4accp / 3 accp, 3 accp, 3 accp, 1 am+4 accp, 2 am + 5 accp. On Th.II–Abd.III, ms-chaetae, as: 1,1/1,0,1. On Abd.III, ms-chaetae long, about as long as s-chaetae ( Fig. 22 ). Number of common chaetae in p-row between s-chaetae and ms-chaetae: 2s1s5s (Abd.I), 3s2s6–7s (Abd.II), 3s2s4–6ms1s (Abd.III), 1– 0,5s 1s2s1s (Abd.IV) ( Figs 24, 25 ). Abd.V with four thick s-chaetae (accp1–3 and am) and two short and thin (accp4–5) ( Figs 22 , 33 ). Abd V and VI fused. Males not seen.

Distribution. Currently known from type locality only.

Remarks. The new species sharply differs from congeners by s-chaetae on Abd.IV and V. Two contrasting spatterns on posterior part of abdomen were known in Folsomotoma :

- 2 or 3 very long accp s-chaetae on Abd. IV and 4 short s-chaetae on Abd.V ( F. boerneri ( Enderlein, 1903) , F. kerguelensis ( Enderlein, 1903) , F. octooculata ( Willem, 1901) , F. subflava ( Salmon, 1949)) .

- 3 short accp s-chaetae on Abd. IV and 4 very long s-chaetae on Abd.V ( F. bioculata ( Womersley, 1934) , F. marionensis ( Deharveng, 1981) , F. punctata ( Wahlgren, 1906)) .

Folsomotoma amyliuae sp. nov. has short s-chaetae on both Abd.IV and V that was unknown in the genus. Thickening of 4 s-chaetae on Abd.V are shared with F. subflava (Campbell Isl.) . In addition, the size of the new species (~ 1mm) is uncommon for the genus — only F. punctata , F. minuta (Salmon) and F. anomala (Salmon) are similarly small. Following Deharveng (1981), the two latter species were probably described basing on immature specimens, or they belong to another genus. Due to its small size F. amyliuae sp. nov. can be easily confused with pale Parisotoma .

Name derivation. We dedicate this species to W.P. Amy Liu, who has contributed to increasing the knowledge of Collembola of South Africa.

Figures

FIGURES 21–25. Folsomotoma amyliuae sp. nov.: 21, ommatidia and PAO; 22, chaetotaxy of posterior part of abdomen; 23, s and bms on Ant.I; 24–25, s- and ms-chaetae on Abd. III–V (24) and Th.II–Abd.II (25). Abbreviations as on Figs 1–10.

FIGURES 26–35. Folsomotoma amyliuae sp. nov. (26-33) and Folsomotoma spp. (34-35): 26–27, appearance, pigmentation (26) and macrochaetae (27); 28, ventral tube, lateral view; 29, distal part of tibiotarsus II; 30, basal part of labium and postlabial chaetae; 31, manubrial thickening; 32, manubrium and proximal part of dens, anterior view; 33–35, s-chaetae: s1 of Abd.IV, s1 and s5 of Abd.V in F. amyliuae (33), Folsomotoma sp.1 (34) and Folsomotoma sp.2 (35).