Folsomia australica, Potapov, Mikhail, Janion-Scheepers, Charlene & Deharveng, Louis, 2017

Potapov, Mikhail, Janion-Scheepers, Charlene & Deharveng, Louis, 2017, Taxonomy of the Cryptopygus complex. II. Affinity of austral Cryptopygus s. s. and Folsomia, with the description of two new Folsomia species (Collembola, Isotomidae), ZooKeys 658, pp. 131-146 : 134-137

Folsomia australica sp. n. Figs 14-21

Type material.

Holotype: adult ♀. Australia, Chiltern National Park, Victoria, heathy dry forest, mostly native, 36°7'53"S, 146°36'20"E, 12.iv.2015, M. Lythe leg. Four paratypes, one adult ♀, one adult ♂and two sub-adult ♀♀ of the same size as adults. Holotype and two paratypes in SAMA, two paratypes in MSPU.

Other material.

10 specimens in ethanol (SAMA). Australia, Victoria, Mt Pilot National Park, 36°18'45"S, 146°33'16"E. 20.vii.2015, M. Lythe leg.

Diagnosis.

Folsomia species with 1+1 ocelli; chaetotaxy of dens 12/6; tridentate mucro; 2 lateral s-chaetae on Abd.V clearly longer than 3 dorsal ones; 2+2 chaetae on anterior side of manubrium.

Description.

Body size from 0.60 (adult male) to 0.75 mm (one of sub-adult females). White, with one black ocellus on each side of the head (Fig. 21). Body of normal shape for the genus. Abd IV, V and VI clearly fused dorsally, Abd.IV and III well separated. Cuticle “smooth”, with fine orthogonal granulation, granules much smaller than chaetae bases. Ocelli 1+1, well-marked only by pigmentation, cuticular cornea weak. PAO wide, constricted, smaller (ca. 0.8) than width of Ant I, about 1.5 as long as inner unguis length (Fig. 21). Maxillary outer lobe with four sublobal hairs, maxillary palp bifurcate. Labral formula as 4/5,5,4. Labium with five papillae ( A–E), ‘guard’ e7 present (whole number of ‘guards’ hard to estimate), with three proximal, four basomedian, and five basolateral chaetae. Ventral side of head with 4+4 postlabial chaetae. Ant.I with three ventral s-chaetae (s) and two small basal ms-chaetae (bms), dorsal and ventral, Ant.II with three bms and one latero-distal s. Ant.III with one bms and with five distal s (including one lateral), without additional s-chaetae. Ant.IV with several tubular s-chaetae. Subapical organite large and roundish, set together with subapical ms, as common for family (Fig. 19). S-chaetae formula 4,3/2,2,2,3,5 (s) and 1,0/0,0,0 (ms). Tergal s-chaetae shorter than common chaetae. Medial s-chaetae on Th. II–Abd.III in mid-tergal position, on Abd. I–III between Mac1 and Mac2. Abd.V with five s-chaetae with three dorsal ones (al, accp1, accp2), almost as long as common chaetae, and two lateral long, macrochaetae-like ( ‘3+2’ pattern) (Figs 14-15). Two lateral s-chaetae often slightly thickened on proximal 2/3 that makes them more distinct. Macrochaetae smooth, 1,1/3,3,3 in number, medial ones on Abd.V shorter than dens (0.6-0.8) and 2.6-3.0 times longer than mucro. Foil chaetae at the tip of abdomen absent. Axial chaetotaxy of Th. II–Abd.III as 9 –10,6–8/4–5,4– 5,4. Th.III with 1+1 ventral chaetae. Unguis without teeth (Fig. 20). Empodial appendage about 0.6 as long as U3. Upper and lower subcoxae of Leg I, II, III with 1,1; 3,6; 5 –6,6– 7 chaetae. Tibiotarsi without additional chaetae on Leg I and II (21 chaetae), and with several additional chaetae on Leg III. Tibiotarsal tenent chaetae pointed, shorter than U3 (0.8-1.0). VT with 3+3 laterodistal and five posterior chaetae, of which four in transversal row, anteriorly without chaetae. Tenaculum with 4+4 teeth and a chaeta. Anterior furcal subcoxae with 8-12, posterior one with five chaetae. Anterior side of manubrium with two pair of chaetae, 2+2 (rarely 1+2) (Figs 16, 17). Posterior side of manubrium with 3+3 laterobasal, 6-7+6-7 on main part, without apical and lateral chaetae (Fig. 18) (shown in the only variant seen). Dens slender, with 12 anterior chaetae arranged as 1,1,2,3,2,3 (Figs 16, 17). Posterior side of dens with few distinct crenulations at the middle, four chaetae on proximal half and two medially. Mucro tridentate. Ratio of manubrium: dens: mucro = 2.9-3.4: 3.6-4.2: 1.

Etymology.

The name is given after the geographical distribution of the new species.

Discussion.

Folsomia australica sp. n. resembles the only other native Australian species of the genus, i.e. Folsomia loftyensis (Womersley, 1934) (after the redescription of Potapov and Greenslade 2010) by chaetotaxy of dens 12/6, tridentate mucro, 1+1 ocelli, ms-formula of body 10/000, differentiation of s-chaetae on Abd.V, and other characters. It differs in having 2+2 chaetae (vs. 4 –5+4– 5 in Folsomia loftyensis ) on the anterior side of manubrium. Juvenile specimens of the two species are probably hard to distinguish. The new species was recorded by Potapov and Greenslade (2010) as " Folsomia sp. aff. loftyensis ". Folsomia australica sp. n. and Folsomia minorae sp. n. are dissimilar indicating that the "austral " members of the genus Folsomia can also be heterogeneous, as in the Northern Hemisphere.

Morphological features of the furca of Folsomia australica and Folsomia loftyensis , especially the tridentate mucro, are shared with several species of Cryptopygus : Cryptopygus tricuspis Enderlein, 1909 (sub-Antarctic), Cryptopygus insignis Massoud and Rapoport, 1968 (South America), Cryptopygus patagonicus Izarra, 1972 (South America), and three unnamed species from South Africa ( Cryptopygus sp. 5, Cryptopygus sp. 6, and Cryptopygus sp. 7, see below). These species probably represent another group of Cryptopygus s.s., dissimilar to Cryptopygus antarcticus , which could be ancestral to the “Australian” species of Folsomia .

Distribution.

Folsomia australica sp. n. is known from two localities in south-eastern part of Australia (Victoria and New South Wales).