Philotella cedrina, Babenko & Shveenkova & Potapov, 2022

Babenko, Anatoly, Shveenkova, Yulia & Potapov, Mikhail, 2022, New species of the genus Philotella Najt & Weiner, 1985 (Collembola, Neanuridae, Pseudachorutinae) from the Russian Far East, Zootaxa 5174 (5), pp. 525-550 : 534-536

Philotella cedrina sp. nov.

Figs 17–21

Type material. Holotype: female, Southern Primorye , «Kedrovaya Pad» State Nature Reserve ( Fig. 1 , point 3), mixed coniferous-broadleaf forest, 43°6.88’N 131°29.23’E, ~ 120 m alt., litter, 27 July 2016. N. Kuznetsova & M. Potapov leg. Paratype: immature male, same data as holotype.

Diagnosis. A species of the genus Philotella characterized by the presence of 3+3 subequal ocelli; the second row of labral setae with two longer and three shorter setae; a labium of the first type; a dorsal chaetotaxy with setae p2 present on Th. II –III but absent on Abd. I –IV; 1+1 setae between sensilla on Abd. V; a complete tibiotarsal chaetotaxy and toothless unguis.

Description. Length (without antennae) of a single available female— 0.34 mm. Habitus typical of the genus. Alive colour unknown, probably rather dark. Tegument granulation strong, especially on abdominal tip.

Antennae clearly shorter than head, Ant. III–IV fused dorsally. Ant. IV with simple or slightly divided apical vesicle; external ms, subapical or and seta i present; six sensilla (S1–S4, S7–S8) on dorsal side of Ant. IV clearly differentiated, blunt and prolonged; few sensilliform setae of various shape also present on its ventral side. Antennal organ of Ant. III typical, inner sensilla small, sgv longer than sgd and curved, ventral ms present. Ant. I–II with 7 and 11 setae, respectively.

Head with 3+3 [?] ocelli, clearly larger than surrounding secondary granules on ocular field. PAO rounded, consisting of 7–9 vesicles, its axis to ocellus B ratio as 1.5–1.7: 1. Buccal cone short and blunt. Maxilla styliform, lamellae not clearly seen. Mandible delicate, with five teeth, two of which tiny and hardly detected. Labrum with a common set of 4/2352 setae of different length, the second row with two longer marginal setae and three smaller median ones ( Fig. 17 ). Main part of labium of the first type with three ordinary setae set in a line and 2+2 axial setae between sensorial elements ( Fig. 18 ); submentum and mentum with usual set of four setae each. Head ventrally with 2+2 postlabial setae.

Dorsal chaetotaxy almost symmetrical ( Fig. 19 ). Ordinary setae short, needle-like, sensilla much longer, their number as usual: 22/11111, lateral sensilla on Th. II and dorsal ones on Abd. IV slightly thickened ( Fig. 21 ), Th. II with lateral ms present as usual. Main characteristics: head usually with unpaired seta d0, ocular field with 3 setae; Th. I with 3+3(2) setae; Th. II–III with 3+3 axial setae (p2 present); dorso-lateral group consisting of 2 ordinary setae (a3 and m4) additionally to sensillum p 3 in backward position; Abd. I–IV with 2+2 axial setae, Abd. V with only 1+1 setae between sensilla.

Thoracic sterna without setae. Ventral tube with 4+4 setae, no seta on sternum of Abd. I, ventral side of Abd. II–III without unpaired axial setae. Furcal remnant in a form of two swellings, each with a seta, on anterior border of Abd. IV. Unpaired anal valve with three hr-setae, paired ones with two such setae, each.

Legs I–III with 1, 2, 2 setae on upper subcoxae, 0, 2, 2 setae on lower subcoxae, 3, 6, 6 setae on coxae, 6, 6, (5)6 on trochanters, and 13, 11, 10 setae on femora. Tibiotarsi with most complete set of setae: 19, 19, 18, seta M present. Unguis toothless.

Remarks. Despite the limited material available, we venture to describe this species, since the holotype appears to be sexually mature ( Fig. 20 ) and has a fairly characteristic morphology and a symmetrical chaetotaxy.

Etymology. The name of the new species is given after its type locality, «Kedrovaya Pad» (Cedar Valley) State Nature Reserve; from Ancient Greek κέδρινος (kédrinos), cedrinus (a, um) in Latin.

Affinities. Philotella cedrina sp. nov. is similar to P. pax sp. nov., except for a reduced number of ocelli, which are not always easy to correctly count. Both these species have a labium of the same type and an almost identical dorsal chaetotaxy. The only noticeable differences in the latter character are the presence of three setae on the ocular field (vs two such setae in P. pax sp. nov.), 1+1 setae between sensilla on Abd. V (vs 2+2 setae in this position in P. pax sp. nov.), and markedly thickened sensilla on Th. II and Abd. IV. In addition, these species are more or less easily distinguishable due to differing lengths of labral setae: in P. cedrina sp. nov., two marginal setae of the second row are longer than the others, while in P. pax sp. nov., there are three such setae in this row (cf. Fig. 17 and Fig. 8 ).

Among the known species of the genus, P. cedrina sp. nov. also resembles the Korean P. miracli , in which the dorsal chaetotaxy is very similar to that of P. cedrina sp. nov., but differs in having three ordinary setae in addition to sensillum p 3 in the dorsolateral group on Th. II–III. Besides the number of ocelli, these species also differ in the types of the labium and the number of tibiotarsal setae.

It is also noteworthy that clearly thickened sensilla on Th. II and Abd. IV, both characteristic of P. cedrina sp. nov., have previously been mentioned also for all three North Korean species. In our material, the differentiation of these sensilla was also detected in P. amurica sp. nov., being especially noticeable in P. alba sp. nov. (see descriptions below).

Figures

FIGURE 1. Map of main sampling plots. 1, Amur Region, Zeya State Nature Reserve; 2, Amur Region, Arkhara; 3, Southern Primorye, «Kedrovaya Pad» State Nature Reserve; 4, Southern Primorye, Ussuri State Nature Reserve; 5, Southern Primorye, Anisimovka, Mount Khualaza; 6, Southern Primorye, Mount Olkhovaya; 7, Southern Primorye, Chuguevka; 8, Southern Pri- morye, Mount Oblachnaya; 9, Southern Primorye, Sikhote-Alin State Nature Reserve; 10, Khabarovsk Territory, Ko Mountains; 11, Khabarovsk Territory, “Arseniev’s granites” Mts. Range; 12, Khabarovsk Territory, Komsomolsk State Nature Reserve; 13, Khabarovsk Territory, Tormasu River; 14, Khabarovsk Territory, Anyuinski National Park.

FIGURES 17–24. Philotella cedrina sp. nov. (17–21) & Philotella aliniensis sp. nov. (22–24): 17; labrum; 18, labium; 19, dorsal chaetotaxy; 20, Abd. V–VI (ventral); 21, lateral sensilla on Th. II–III, sensilla of Abd. III–V (top down); 22, labium; 23, ocular field and PAO; 24, dorsal chaetotaxy. Scales. Figs 19, 24: 0.1 mm; 17–18, 20–23: 0.01 mm.

FIGURES 2–9. Philotella pax sp. nov.: 2, dorsal chaetotaxy; 3, ventral chaetotaxy of abdomen; 4, Ant. III–IV (lateral view); 5, ocular field and PAO; 6, maxillary head; 7, left and right mandibles; 8; labrum; 9, labium. Scales. Figs 2–3: 0.1 mm; 4–9: 0.01 mm.