Plutomurus kharagauliensis Barjadze, Kováč & Parimuchová, 2022

Barjadze, Shalva, Parimuchová, Andrea, Raschmanová, Natália, Maghradze, Eter & Kováč, Ľubomír, 2022, Two new species of Plutomurus Yosii (Collembola: Tomoceridae) from the Caucasus and central Europe, Zootaxa 5169 (3), pp. 252-266 : 254-258

Plutomurus kharagauliensis Barjadze, Kováč & Parimuchová sp. nov.

Figs 3–15

Type locality. GEORGIA, Imereti region, Kharagauli municipality, close to the village Amashuketi, Zemo Imereti Plateau karst massif, Kozmani Cave , 644 m asl .

Type material. Holotype: Female on slide, dark zone, hand collecting, 27.xi.2021, leg. Sh. Barjadze, E. Maghradze, M. Gogshelidze, code GEOKOZ20211127-01 ( IZISU) ; Paratypes (n=13): eight specimens on slides with the same data as holotype, code GEOKOZ20211127-02, 03, 04, 05, 08, 09, 10, 11 ( IZISU) ; one specimen on slide, twilight zone, 14.ix.2021, leg. E. Maghradze, GEOKOZ20210914-14 ( IZISU) ; two specimens on slides, dark zone, 27.xi.2021, leg. Sh. Barjadze, E. Maghradze, M. Gogshelidze, code GEOKOZ20211127-06, 07 ( UPJ) ; two specimens on slides, twilight zone, 14.ix.2021, leg. E. Maghradze, GEOKOZ20210914-12, 13 ( UPJ) .

Description. Body length 2.44–4.02 mm ( Fig. 3 ).

Colour. Body grey colored.

Scale distribution. Scales are present dorsally on Ant. I–II, head, Th. and Abd. segments, all leg segments, both sides of ventral tube and ventral side of furca.

Head. Ratio of antennal length: head length as 2.67–3.10. Ant. III–IV annulated. Eye patch typical for genus, with six well developed eyes ( Fig. 12 ). Head dorsally with one unpaired (A 0), and seven paired Mc: two anterior (A 2, A 3), two interocular (S 2, S 4) and three postocular (Pa 3, Pa 4, Pa 5) distributed as in Fig. 12 . Posterior margin of head with a row of mesochaetae. Prelabral and labral chaetae smooth: prelabral chaetae four (2+2) ( Fig. 4 ); labrum with 554 papillate chaetae as typical for genus; distal margin of labrum with four elongate, thin–walled, flexible papillae. OML trifurcate, basal chaetae shorter than apical process; OML with four chaeta-like processes.

Body. Dorsal bothriotrichal formula as 2,1/0,0,1,2,0 ( Figs 13–14 ). Dorsal Mc formula: 4,2/3,3,4,6,3–4 ( Figs 13–14 ). Thoracic macrochaetotaxy as in Fig. 13 . Th. II with two anterior (m 3, m 4) and two posterior (p 3, p 5) Mc; Th. III with two posterior (p 3, p 4) Mc. Abdominal macrochaetotaxy as in Figs 14–15 : Abd. I–II each with three long posterior Mc (m 2, m 3, m 4); Abd. III with four long Mc: two anterior (m 2, m 6) and two posterior (p 1, p 6) and one short Mc (p 7) as typical for genus; Abd. IV with six posterior Mc: two long (C 6, E 3) and four short Mc (A 6, B 6, D 3, T 7) ( Fig. 15 ); Abd. V with 2–3 posterior (p 2, p 3 or p 2, p 3, p 4) long Mc and one long Mc laterally ( Fig. 14 ).

Mc length: Mc on Th. II (m 3, m 4, p 3, p 5) and Th. III (p 3, p 4)—120–167 µm; Mc on Abd. I–II (m 2, m 3, m 4) and Abd. III (m 2, m 6, p 1, p 6)—178–220 µm; Mc on Abd. IV-E 3 238 µm, C 6: 168 µm (found only in a single specimen), A 6: 93–135 µm, B 6: 110–140 µm, D 3: 100–155 µm and in T 7 Mc length is unknown (missing in all individuals). Diameter of Mc sockets on Abd IV-E 3 and C 6: 8–10 µm, 4 short Mc (A 6, B 6, D 3, T 7) subequalor in diameter.A 6 slightly longer (5.5–7.5 µm) than in remaining 3 short Mc: B 6: 5.5–6.5 µm; D 3: 5.0–6.5 µm and T 7: 5.5–6.0 µm.

Legs. Hind legs with well–developed trochanteral (17–36 chaetae) and femoral (20–35 chaetae) organs ( Fig. 9 ), with several elongated chaetae; tibiotarsal spine formula as 002, posterior side of tibiotarsus III with two outstanding inner, Spine-like chaetae, (arrows in Fig. 10 ). Tenent hair capitate ( Figs 5, 10 ). Ratio of claw III: Emp. III: tenent hair III as 1.66–3.14: 0.91–1.71: 1. Inner edge of claw on all legs with one characteristically minute proximal unpaired tooth (as in Fig. 5 ) and 2–4 distal unpaired teeth, 3–5 in total (b, c, d in Fig. 5 ). Claw with long pseudonychia ( Figs 5, 10 ). Ratio of pseudonychium III: claw III inner edge as 0.38–0.62: 1. Empodium lanceolate, tapered, with 2 internal lamellae bearing 0–6 teeth ( Fig. 5 ).

Ventral tube. Hirsute, in one specimen anterior basal, posterior basal and apicolateral sides with 36, about 24 and 35 smooth chaetae respectively ( Fig. 8 ).

Tenaculum. Corpus with one smooth chaeta; rami with 4 + 4 teeth ( Fig. 6 ).

Furca. Ratio manubrium: dens: mucro as 5.54–9.71: 8.11–11.43: 1. Outer margin of basal segment of dens with 2–6 apically acuminate macrochaetae (sockets with arrows in Fig. 11 ). Inner edge of dens with well differentiated spines (spinal sockets shown in Fig. 11 ); spines on basal segment of dens forming 2–3 short and poorly organized rows with 1–3 large spines apically; spines on distal segment of dens forming a single row extending maximum 1 / 3 or 1 / 2 of length of distal segment of dens; proximal edge of distal segment of dens always with small spines intercalated between long spines, terminal one always largest long spine in row (dental sockets in Fig. 11 ). Dental formula variable, as 4–11 I–III /1–7 I 1–4 I(II) 0–2 I 0–2 I 0–2 I (Arabic numbers represent small spines; Roman numerals in bold and Italics represent large spines, on basal/distal segment of dens). Mucro with two basal, 0 intermediate and two distal teeth (202 formula) ( Fig. 7 ).

Variability. All constant and variable characters are given in Tables 1–2 .

Discussion. The new species is most similar to P. birsteini Djanashvili & Barjadze, 2011 by the combination of the following characters: 1) number of prelabral chaetae (2+2); 2) shape of tenent hair (capitate); 3) formula of tibiotarsal spine-like chaetae (002); 4) number of eyes—6 and 5) number of Mc on Th. II ( Djanashvili & Barjadze 2011; Barjadze et al. 2020a). Both species are cave dwellers.

The new species differs from P. birsteini by the number of Mc on the head and abdominal terga: 1) three postocular Mc on the head dorsum present in the new species, while 2 Mc in P. birsteini and 2) Abd. IV with six Mc in the new species, while P. birsteini has three (Barjadze et al. 2020a). Plutomurus birsteini was described from eleven caves located in five different karst massifs of western Georgia and molecular investigations (COI) show that P. birsteini is a complex of genetically distinct cryptic species (Barjadze, unpublished data).

Etymology. The specific name originates from the type locality––Kharagauli district in which the Kozmani Cave is situated.

Ecology. It is a troglophilous species, considering the presence of body pigment and 6+6 well-developed eyes. It occupies both twilight and dark zones of the cave.

Distribution. This species is known only from a single cave. This cave is the remotest one from Zemo Imereti plateau karst massif and it is isolated from other known caves in the same karst massif ( Tatashidze et al. 2009). The new species is the first known taxon from Kozmani Cave.

Figures

FIGURE 3. Habitus of Plutomurus kharagauliensis sp. nov. (scale bar: 0.5 mm).

FIGURES 4–11. Plutomurus kharagauliensis sp. nov. 4, Prelabral chaetae (bar: 0.04 mm); 5, Claw complex III (a, basal small tooth to internal lamellae; b, largest unpaired tooth and c and d additional unpaired teeth) (bar: 0.05 mm); 6, Tenaculum (bar: 0.06 mm); 7, Mucro, chaetae and chaetal sockets omitted (bar: 0.02 mm); 8, Ventral tube (bar: 0.08 mm); 9, Trochanteral and femoral organs (bar: 0.06 mm); 10, Hind tibiotarsus, with spine-like chaetae (arrows on them) (bar: 0.04 mm); 11, Dens with sockets of dental spines and lateral macrochaetae (arrows on them) (bar: 0.05 mm).

FIGURES 12–14. Dorsal chaetotaxy in Plutomurus kharagauliensis sp. nov. 12, Head.A: Anterior macrochaetae, B: interocular Mc, C: postocular Mc; 13, Th. II–III; 14, Abd. I–V (big ovals and round circles near Ant. I represent eyes; large black cir- cle—macrochaeta; open circles—mesochaeta; squares with dots—bothriothricha; circles with a slash represent pseudopores).

FIGURE 15. Plutomurus kharagauliensis sp. nov. Macrochaetae complex on Abd IV (bar: 50 μm).