Plutomurus pichkhaiai Barjadze, Jordana & Soto-Adames, 2018

Barjadze, Shalva, Jordana, Rafael, Baquero, Enrique, Giordano, Rosanna & Soto-Adames, Felipe N., 2018, Two new species of Plutomurus Yosii (Collembola, Tomoceridae) from the Caucasus, Zootaxa 4526 (1), pp. 29-40 : 36-38

Plutomurus pichkhaiai Barjadze, Jordana & Soto-Adames sp. nov.

Figs 23–26

Type locality. GEORGIA, Samegrelo– – Zemo Svaneti , Chkhorotsku , near Garakha, Garakha Cave, 42°31'47.22"N, 42°10'39.18"E, 203 m alt .

Type material. Holotype, female on slide: dark zone, 13.ii.2014, leg. Sh. Barjadze (code GeoGar20140213– 02). Paratypes (same as holotype): 2 females on slides (code GEOShu20140213–01 and 03). Two specimens mounted on SEM stubs (GeoGar20140213–04 and 05). Three specimens in ethanol (GeoGar20140213–06, 07 and 08). Paratypes: two females on slide, dark zone, 30.iv.2017, leg. G. Nebieridze (GeoGar20170430–01 and 02); one female on slide, twilight zone, 30.iv.2017, leg. G. Nebieridze (GeoGar20170430–03). Two specimens ( FSCA 108– 109, males) same date as holotype but 30.iv.2017, leg. G. Nebieridze. The material from 13.ii.2014 was previously mentioned as “ Plutomurus sp. 4” in Barjadze et al. (2015) and as “ Plutomurus sp. 1” in Barjadze et al. (2016).

Additional material. GEORGIA, Samegrelo–Zemo Svaneti, Chkhorotsku, Letsurtsume, Letsurtsume Cave, 42°32'21.4"N, 42°06'47.3"E, 183 m alt. Two specimens ( FSCA 110, female and FSCA 111 male) on slides, dark zone, 29.iv.2017, leg. Sh. Barjadze and two specimens (GeoLet20170429–01, male) and (GeoLet20170429–02, female) on slides, dark zone, 29.iv.2017, leg. Sh. Barjadze. Holotype and paratypes 01, 03–08 deposited at MZNA ; paratypes: GeoGar20170430–01, 02, 03 at IZISU , and N108–109 at FSCA. Additional materials (GeoLet20170429–01 and 02) at IZISU, and N110–111 at FSCA.

Description. Body length up to 3.76 mm excluding antennae.

Color pattern. Habitus and distribution of grey pigment as in Fig. 23 .

Scale distribution. As in P. shurubumuensis sp. nov.

Head. Ratio of body to antennae length up to 0.85. Number of eyes unclear, observations under compound microscope show 3–5 eyes, but field where eyes sit often distorted. Head dorsally with 1 unpaired, and 6 paired Mc as in P. shurubumuensis sp. nov. Prelabral chaetae 3+3, labral chaetae and papillae typical for genus. Maxilla as in P. shurubumuensis sp. nov., but lamella N5 sometimes appearing Y-shaped ( Fig. 24 ) Proximal chaetae of labium 16–17. Basomedial field with 22–23 smooth chaetae; basolateral field with 5 chaetae.

Body. Dorsal Mc formula 4,2//3,3,4,3,4 ( Figs 25–26 ). Abd. IV with 7 differentiated chaetae, chaeta #7 always a large Mc, chaetae N2 and N3 always developed into a small Mc ( Fig. 26 ), other chaetae always small, mesochaeta-like as in P. shurubumuensis sp. nov.

Legs. Hind legs with well-developed trochanteral (16–30 chaetae) and femoral organs (25–36 chaetae) (n=7). Tibiotarsal outstanding spine-like chaetae formula as 002. Tenent hair acuminated, as in P. shurubumensis sp. nov. Ratio hind unguis: unguiculus: tenent hair as 1.50–3.00: 1.50–2.28: 1 (n=7). Inner edge of unguis on all legs with 2 unpaired teeth, proximal tooth minute, distal tooth evidently larger; lateral outer teeth 0.38–0.83 times length of inner edge of uguis (n=7). Unguiculus lanceolate and tapered, with 0–7 inner teeth.

Collophore. Chaetotaxy as in P. shurubumuensis sp. nov.

Furcula. Ratio manubrium: dens: mucro as 3.52–5.00: 7.17–8.17: 1 (n=6, including holotype). Outer margin of dens with 3–5 acuminate spine–like macrochaetae. Inner edge of dens with a variable number of basal spines; row of spines on distal segment of dens extending between 24–28% (3 out of 6 individuals=26%) of dens total length. Dental spines formula variable as 5–14 II–IV /8–13 II–IV. Mucronal teeth formula 202.

Variation. The number of teeth on inner lamellae of the unguiculus varies from 0 to 7. The number of dental spines is also variable. Ratio of hind unguis: unguiculus: tenent hair, and ratio of manubrium: dens: mucro are also variable.

Discussion. Plutomurus pichkhaiai sp. nov. is the only eyed member of the genus with 3+3 prelabral chaetae, 2 spines on the inner edge of the hind legs, and 3 posterior Mc on Abd. IV. The new species is most similar to P. shurubumuensis sp. nov., from which it differs in the number of posterior Mc on Abd. IV, in mtDNA sequence and cave formation as described above for P. shurubumuensis sp. nov. From P. kelasuricus the new species differs in having 2 inner spine–like chaetae on the inner edge of the hind tibiotarsus (only 1 in P. kelasuricus ); in addition, P. pichkaiai sp. nov. was collected in Garakha and Letsutsume caves, part of the Migaria karst massif formation, whereas P. kelasuricus was collected 100 km to the northwest, in Kelasuri Cave, which is part of the Tsebelda karst massif formation.

Etymology. The epithet honours Mr. Igor Pichkhaia, who has worked on the popularization of local caves in Chkhorotsku district during several decades.

Ecology. The presence of body and eye patch pigmentation suggest this is a troglophilous species.

Figures

FIGURE 23. Plutomurus pichkhaiai sp. nov. Habitus, from Letsurtsume Cave (bar: 0.5mm).

FIGURES 24–26. Plutomurus pichkhaiai sp. nov. 24, Maxillary lamella N5 (bar: 0.01 mm); 25, Dorsal chaetotaxy of thoracic segments. II-III; 26, Dorsal chaetotaxy of abdominal segments I–VI.