Lepidocyrtus (Setogaster) coorongensis 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 : 374-375

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

Figs 23, 24 , 26–34 , Tab 1

ZooBank: urn:lsid:zoobank.org:act:9F9216DC-AB15-4F52-AC8B-6924AC6F5322

Type material. Holotype: female on one slide (slide code T 22515), Australia, South Australia, Hindmarsh Island (in Coorong region ), 10 m above sea level, S35°31’21” E138°52’38”, pit-fall traps, 1.x.2013, P. Greenslade leg. Paratypes: one male on slide code T 22516 , 8 specimens of unknown sex on slide codes LP340-1 , LP340-2 , LP3404 , LP340-5 , LP340-6 , LP340-7 , LP340-9 , LP340-10 , and 66 specimens on absolute alcohol (sample code LP340 ), same data as holotype . Holotype and paratype slide code T 22516 deposited at the Museum of Victoria ( Melbourne , Australia); other paratype deposited at the E. Mateos collection (University of Barcelona, Barcelona, Spain) .

Etymology. The specific name refers to the area in South Australia where the species was found, the Coorong region.

Diagnosis. Body without pigment; 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 without chaeta a6; Abd.II m3 short ciliated macrochaeta, m5 smooth microchaeta; Abd.III with lateral tuft of ±20 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 smooth microchaetae, 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) 0.9–1.3 mm (Holotype 1.3 mm). Mesothorax not projecting overhead. Body dorsoventrally compressed; general body pigmentation pale fawn/yellow; blue pigment only present on Ant.II–IV; densely black pigmented ocular areas ( Fig. 26 ).

Antenna without scales. Antennal length to head diagonal length ratio (head diagonal measured from cervical edge to apex of mouth part) ≈ 1.3. Relation of antennal joints I–IV as 1:2:2:3. Dorsal Ant.I-organ present. Ant.III organ composed of two sub-cylindrical sensory rods partially covered by 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, three smooth sublobal appendages, and a minute distal process (as L. agricolus sp. nov., Fig. 4 ). Lateral process of outer labial papilla short, finger-shape, tip not reaching apex of papilla (as L. agricolus sp. nov., Fig. 5 ). Labium ( Figs 27–28 ) 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; chaeta R shorter, ratio M 2 /R = 2; postlabial chaetotaxy as in L. agricolus sp. nov. ( Fig. 6 ), with all chaetae ciliated, without spines, 3 chaetae in row I (along ventral cephalic groove), 1 chaeta in row C, 3 chaetae in row E, 2 chaetae in row L, and 4 chaetae in row O.

Dorsal head ( Fig. 29 ) with macrochaetae A0, A2a and A2; A2a of length equal 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 30 ; with a lateral S-microchaeta (ms); chaeta a6 absent; chaeta m5 present or absent depending on the specimens. Abd.II–III chaetotaxy as L. agricolus sp. nov. ( Fig. 11–14 ). Abd.II chaetae ml and a2p absent; chaetae mi, a2, ml and ll fan-shaped; chaeta m3 short ciliated macrochaeta, ratio m3/m3e = 1.4; m5 smooth microchaeta. Abd.III with S-chaetae as and ms; chaeta d3 absent; chaetae mi, ml, a2, li, lm, ll, a6, im, and em fan-shaped, of which a6 and li larger (paddle-like); am6 fan-shaped chaeta; p6 and pm6 broad ciliated macrochaetae; a8 thin ciliated macrochaeta; p8 thin ciliated macrochaeta or smooth microchaeta; with lateral tuft of ±20 long ciliated filaments. Abd.IV chaetotaxy as in Fig. 31 ; Sm smooth microchaeta; B4 and B5 broad ciliated macrochaetae, B6 thin ciliated macrochaeta with socket of minor diameter than macrochaetae B4 and B5; F2 and F3 smooth microchaetae; Fe4 thin ciliated macrochaeta; with 7+7 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 finely cilated, chaetae m, D1, pi and pe fan-shaped, from which m and D1 larger (paddlelike); chaeta a bilobed and cliated. Abd.V ( Fig 32 ) with dorsal S-chaetae as, acc.p4 and acc.p5.

Ventral tube without scales, with 12+12 ciliated chaetae on anterior side ( Fig. 33 ) and 10 ciliated chaetae on posterior side; each lateral flap with maximum of 8 ciliated chaetae and 5 smooth chaetae.

Legs without scales. V-shaped trochanteral organ (leg III) with maximum of 11 smooth straight chaetae arranged in triangular shape (as in L. agricolus sp. nov., Fig. 20 ). Unguis ( Fig 34 ) with well-developed basal pair of teeth at 50% from base of the inner edge, and with two small inner teeth at 70% 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 ≈ 1.6; 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, 2–3 inner chaetae, and 2–3 outer chaetae. Dentes with small, rounded basal tubercle (difficult to see in some 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) coorongensis sp. nov. is close to the other two new species described, L. (S.) agricolus sp. nov. and L. (S.) nashi sp. nov., and also to species listed in Table 1 . Cephalic chaeta M2 and Abd.IV chaetae F2 and F3 as smooth microchaetae in L. (S.) coorongensis sp. nov. are good diagnostic characters differentiating this species and L. (S.) agricolus sp. nov. (with these chaetae as ciliated macrochaetae). The best diagnostic character between L. (S.) coorongensis sp. nov. and L. (S.) kuakea is the morphology of cephalic chaeta M2, smooth microchaeta in the former and cilated macrochaeta in the latter. Body without pigment in L. (S.) coorongensis clearly separates this species to the pigmented L. (S.) fasciatus , L. (S.) nashi sp. nov., L. (S.) nigrosetosus , L. (S.) praecisus , and A. zhujiensis .

The new species appears to be locally endemic but as it was collected on a large island adjacent to the coast and with similar vegetation, we predict it is more widespread in southern South Australia than these records suggest. The island had been heavily impacted by agriculture in the past, by clearing, grazing and planting of broad acre arable crops but is now being rehabilitated by plantings of native vegetation in some areas. The new species was collected on several of the rehabilitated sites but only those with a good covering of leaf litter and it was the second most abundant species found on the eighteen sites sampled with nearly 100 pitfalls set for a week in summer.

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 26–30. Lepidocyrtus (Setogaster) coorongensis sp. nov. 26, habitus (dorso-lateral view) (figure from Mateos & Greenslade 2015); 27, labium photograph; 28, labium chaetotaxy (left side); 29, dorsal head chaetotaxy (left side), black circles—ciliated macrochaetae sockets; chaetotaxy below microchaetae pa row as in L. (S.) agricolus sp. nov. (Fig. 7); 30, Abd.I dorsal chaetotaxy (left side), the arrow points to chaeta m5 wich is present or absent depending on specimens.

FIGURES 31–34. Lepidocyrtus (Setogaster) coorongensis sp. nov. 31, 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; 32, Abd.V chaetotaxy (left side), black circles—ciliated chaetae sockets (the size of the circles is proportional to chaetae length); 33, ventral tube, anterior side (left side); 34, 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 11–12. Lepidocyrtus (Setogaster) agricolus sp. nov. 11, Abd.II chaetotaxy photograph (left side); 12, Abd.II chaetotaxy (left side).

FIGURES 13–14. Lepidocyrtus (Setogaster) agricolus sp. nov. 13, Abd.III chaetotaxy (left side), dotted rectangle delimits area shown in figure 14, dotted circular area indicates the morphology of chaeta p8 in some specimens; 14, Abd.III chaetotaxy photograph (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).