Lepidocyrtus (Setogaster) nashi Mateos & Greenslade, 2021

Mateos, Eduardo & Greenslade, Penelope, 2021, Towards understanding Lepidocyrtus Bourlet, 1839 (Collembola, Entomobryidae) II: new Australian species, Zootaxa 4981 (2), pp. 365-387 : 378-383

Lepidocyrtus (Setogaster) nashi Mateos & Greenslade sp. nov.

Figs 23, 24 , 35–47 , Tab 1

ZooBank: urn:lsid:zoobank.org:act:B8062D31-0B0B-4F0B-971F-EB5EC32ECEF8

Type material. Holotype: female on two slides (head and body separated, code T 22517), Australia, Victoria State, Tagels, Mt Bogong , 1868 m above sea level, S36°41’21” E147°18’24”, in pitfalls under snow in alpine grassland, 14.i.2012, M. Nash leg. Paratypes: one male on slide code T 22518 , 4 specimens of unknown sex on slide codes LP307-1 , LP307-2 , LP307-4 , LP307-5 , and 2 specimens on absolute alcohol (sample code LP307 ), same data as holotype . Holotype and paratype slide T 22518 deposited at the Museum of Victoria ( Melbourne , Australia); other paratype deposited at the E. Mateos collection (University of Barcelona, Barcelona, Spain) .

Etymology. The new species was named after the collector, Michael Nash who has been assiduously collecting Collembola for the junior author for many years.

Diagnosis. With blue colour present on Ant.I–IV, dorsal and ventral head, Th.II to Abd.IV and coxae, trochanters and femora of three pair of legs; antenna, legs and dorsal side of manubrium unscaled; Ant.IV tip with T-chaeta; eyes G and H strongly reduced; labial chaetotaxy M 1 M 2 rEL 1 L 2;dorsal macrochaetae formula A0A2aA2/00/01*00+3 (*short ciliated macrochaeta); without dorsal macrochaetae from Th.II to Abd.I; Abd.I with chaeta a6; Abd.II m3 short ciliated macrochaeta, m5 smooth microchaeta; Abd.III with lateral tuft of 20–25 long ciliated filaments; Abd. IV trichobothria T2 and T4 close to each other, chaetae C1p, T3 and D1p in triangular pattern, chaeta a ciliated and bilobed, chaetae D1 and m ciliated and paddle-like, chaetae F2 and F3 ciliated macrochaete, with two psp on lateral position; unguis with a basal pair of teeth and two small inner teeth; unguiculus lanceolate and with serrated outer margin; spatulate tibiotarsal tenent hair; dentes with small, rounded basal tubercle; mucronal spine with spinelet.

Description. Adult body length (without head and furca) 1.0– 1.3 mm (Holotype 1.3). Mesothorax not projecting overhead. Body dorsoventrally compressed. Blue colour present on Ant.I–IV, dispersed spots on dorsal and ventral head, on Th.II to Abd.III, mid-dorsal band on Abd.IV, and coxae, trochanters and femora of three pair of legs; densely black pigmented ocular areas ( Fig. 35 ).

Antenna without scales. Antennal length to head diagonal length ratio (head diagonal measured from cervical edge to apex of mouth part) ≈ 1.4. Relation of antennal joints I–IV as 1:1.6:1.7:2.7. Dorsal Ant.I-organ present. Ant. III organ composed of two subcylindrical sensory rods partially covered by an integumentary fold. Ant.IV with subapical mushroom-shaped chaeta (T-chaeta), without apical bulb.

Clypeus and labrum as L. agricolus sp. nov. ( Fig. 3 ). Clypeus with four lateral chaetae (2 L1 and 2 L2), four facial chaetae in two rows, and three prefrontal chaetae (1 pf0 and 2 pf1), all these chaetae ciliated. Labrum with ciliated prelabral chaetae and smooth labral chaetae in typical number 4/5,5,4; chaetae of apical row thicker than those in other rows. Closed inverted V-shaped labral apical intrusion; labral papillae smooth. Maxillary palp outer lobe with two subequal smooth chaetae and four smooth sublobal appendages, the tiny distal process that is present in the other two species described above (see Fig. 5 ) has not been observed ( Fig. 36 ). Lateral process of outer labial papilla short, finger-shape, tip not reaching apex of papilla ( Fig. 37 ). Labium ( Figs 38–39 ) with five smooth proximal chaetae at the base of labial palp; labial anterior row formed by five smooth chaetae (a1–a5); posterior row formed by ciliated chaetae with formula M 1 M 2 rEL 1 L 2; r vestigial smooth microchaeta, ratio M 2 /r = 9; postlabial chaetotaxy as in L. agricolus sp. nov. ( Fig. 6 ), with all chaetae ciliated, without spines, 3 chaetae in row I (one paratype asymmetric, with 3+4 ciliated chaetae on this position), 1 chaeta in row C, 3 chaetae in row E, 2 chaetae in row L, and 4 chaetae in row O.

Dorsal head ( Fig. 40 ) with macrochaetae A0, A2a and A2; A2a length equal or longer than A2; chaeta Pa5 absent.Interocular chaetotaxy with ciliated chaetae s, t, p, and 3 scales; eyes G and H small and difficult to see on the slides. Th.II–III dorsal chaetotaxy as L. agricolus sp. nov. ( Figs 8–9 ). Th.II with 2 lateral S-chaetae (al and ms) and without macrochaetae in dorsal position. Th.III with a lateral sensillum (al) close to several ciliated chaetae. Abd.I dorsal chaetotaxy as in Fig. 41 , with chaeta m5 and a lateral S-microchaeta (ms) external to a6. Abd.II chaetotaxy as in Fig. 42 ; chaetae ml and a2p absent; chaetae mi, a2, ml and ll fan-shaped; chaeta m3 short ciliated macrochaeta, ratio m3/m3e = 1.2; chaeta a6 present; m5 smooth microchaeta. Abd.III chaetotaxy as in Fig. 43 ; with S-chaetae as and ms; chaeta d3 present on one specimen, absent on the rest; chaetae mi, ml, a2, li, lm, ll, a6, im, em and am6 fan-shaped, of which a6 and li larger (paddle-like); p6 and pm6 broad ciliated macrochaetae; a8 and p8 thin ciliated macrochaetae; with lateral tuft of 20–25 long ciliated filaments. Abd.IV chaetotaxy as in Fig. 44 ; Sm smooth microchaeta; B4 and B5 broad ciliated macrochaetae, B6 thin ciliated macrochaeta with socket of minor diameter than macrochaetae B4 and B5; F2 broad ciliated macrochaeta; F3 thin ciliated macrochaeta; Fe4 thin ciliated macrochaeta; with 4+4 dorsal long S-chaetae on anterior region; with two lateral psp located external to chaeta r4. In the Abd.IV anterior bothriotrichal complex the ratio of distances between T2–T4/C1p ≈ 3; bothriotrichum T2 without accessory chaeta s; chaetae C1p, D1p and T3 forming a triangle (as in L. agricolus sp. nov., Fig 17 ); chaeta C1p strongly ciliated (Holotype) or finelly cilated (Paratypes), chaetae m, D1, pi and pe fan-shaped, from which m and D1 larger (paddle-like); chaeta a bilobed and cliated. Abd.V ( Fig. 45 ) with dorsal S-chaetae as, acc.p4 and acc.p5.

Ventral tube without scales, with 10+10 ciliated chaetae on anterior side and 9 ciliated chaetae on posterior side (as in L. agricolus sp. nov., Fig 19 ); all chaetae on posterior side ciliated; each lateral flap with maximum of 6 ciliated chaetae and 6 smooth chaetae.

Legs without scales. V shaped trochanteral organ (leg III) with maximum of 15 smooth straight chaetae arranged in triangular shape ( Fig. 46 ). Unguis ( Fig. 47 ) with well-developed basal pair of teeth at 42% from base of the inner edge, and with two small inner teeth at 67% and 84% from base of inner edge, respectively (apical tooth smaller); unguiculus lanceolate and with serrated outer margin; spatulate tibiotarsal tenent hair and acuminate supra-empodial chaeta; ratio tenent hair/supra-empodial chaeta ≈ 2; ratio unguis inner edge/tenent hair ≈ 1.

Manubrium without scales on dorsal surface; ventro-apical end with 2+2 ciliated chaetae; manubrial plate with two psp, 3 inner chaetae, and 3 outer chaetae. Dentes with small, rounded basal tubercle (difficult to see in several specimens). Mucronal basal spine with spinelet (as in L. agricolus sp. nov., Fig. 22 ).

Pseudopores distribution as in L. (S.) agricolus sp. nov. ( Figs 23–24 ).

Discussion. Lepidocyrtus (Setogaster) nashi sp. nov. is close to the other two new species described, L. (S.) agricolus sp. nov. and L. (S.) coorongensis sp. nov., and to the other species listed in Table 1 . Body with blue pigment and labium with smooth vestigial microchaeta r are good diagnostic characters differentiating L. (S.) nashi sp. nov. from species L. (S.) agricolus sp. nov., L. (S.) coorongensis sp. nov. and L. (S.) kuakea ( Table 1 ). Acuminate unguiculus in L. (S.) nashi sp. nov. clearly separates this species to the other pigmented species listed in Table 1 .

The new species appears to be locally endemic and restricted to alpine grassland habitat on Mt Bogong where it is active under snow. The plant species present in the area were Celmisia costiniana (70%), Poa fawcettiae (20%), Luzula acutifolia (5%), and assorted herbs (5%) including Trachymene humilis and Aciphylla glacialis . A number of other invertebrates have been described as restricted to this habitat and locality ( Greenslade & Slatyer 2017, Braby & Wurtz 2018). Rocky crevices here are an aestivation site for the Bogong Moth, an important food source for the Mountain Pygmy Possum. This fauna is being impacted adversely by climate change resulting in reduced snow cover as well as by increasing tourism. There is anecdotal evidence of visitors interfering with aestivating moths.

Figures

FIGURES 23–25. Lepidocyrtus (Setogaster) agricolus sp. nov., body pseudopores distribution (black dots); 23, dorsal region; 24, lateral and ventral regions; 25, Abd.IV lateral view.

FIGURES 35–40. Lepidocyrtus (Setogaster) nashi sp. nov. 35, habitus (lateral view) (figure from Mateos & Greenslade 2015); 36, maxillary palp photograph; 37, outer labial papilla photograph; 38, labium photograph; 39, labium chaetotaxy (left side); 40, dorsal head chaetotaxy (left side), black circles—ciliated macrochaetae sockets; chaetotaxy below microchaetae pa row as in L. (S.) agricolus sp. nov. (Fig. 7).

FIGURES 41–43. Lepidocyrtus (Setogaster) nashi sp. nov. 41, Abd.I dorsal chaetotaxy (left side); 42, Abd.II dorsal chaetotaxy (left side); 43, Abd.III dorsal chaetotaxy (left side), black circles—lateral filament sockets (d3 inside dotted rectangle indicates the position of this chaeta, presence only in one specimen).

FIGURES 44–47. Lepidocyrtus (Setogaster) nashi sp. nov. 44, Abd.IV chaetotaxy (left side), large black circles—broad ciliated macrochaetae (bcM), small black circles—thin ciliated macrochaetae (tcM), S—long S-chaetae, as and ps—short S-chaetae; 45, Abd.V chaetotaxy (left side), black circles—sockets of ciliated chaetae proportional to chaetal length; 46, trochanteral organ; 47, third leg apex with unguis, unguiculus, tenent hair and supra-empodial chaeta.

FIGURES 1–7. Lepidocyrtus (Setogaster) agricolus sp. nov. 1, habitus in slide (dorsal view); 2, Ant.IV apex showing T-chaeta (arrow); 3, clypeus, prelabrum and labrum chaetotaxy plus labral papillae; 4, maxillary palp (left side); 5, outer labial papilla (lateral view); 6, labium and postlabium chaetotaxy (right side), p.c.—proximal chaetae of labial palp; 7, dorsal head chaetotaxy (left side), black circles—ciliated macrochaetae sockets.

FIGURES 8–10. Lepidocyrtus (Setogaster) agricolus sp. nov. 8, Th.II dorsal chaetotaxy (left side); 9, Th.III dorsal chaetotaxy (left side); 10, Abd.I dorsal chaetotaxy (left side).

FIGURES 15–17. Lepidocyrtus (Setogaster) agricolus sp. nov. 15, Abd.IV chaetotaxy (left side), large black circles—broad ciliated macrochaetae (bcM), small black circles—thin ciliated macrochaetae (tcM), S—long S-chaetae, as and ps—short Schaetae; dotted rectangle delimits area shown in figures 16 and 17; 16, Abd.IV bothriotrichal complex photograph; 17. Abd.IV bothriotrichal complex showing the triangular pattern of chaetae C1p, D1p and T3.

FIGURES 18–22. Lepidocyrtus (Setogaster) agricolus sp. nov. 18, Abd.V chaetotaxy (left side), black circles—sockets of ciliated chaetae proportional to chaetal length; 19, ventral tube, anterior side (left side); 20, trochanteral organ; 21, apex of third tibiotarsus with unguis, unguiculus, tenent hair and supra-empodial chaeta (posterior view); 22, mucro showing basal mucronal spine with spinelet (lateral view).