Folsomia minorae, 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 : 132-134

Folsomia minorae sp. n. Figs 1-6, 7-13

Type material.

Holotype: adult ♀. New Zealand, southern South Island, Central Otago, Pisa Range, 44°52'03"S, 169°9'33"E, 1700 m a.s.l., in soil and debris under Dracophyllum muscoides cushion, 18.ii.2014, coll. M. Minor (on slide). Paratypes. 10 paratypes, subadult ♀♀ and ♂♂of similar size with holotype, 7 of which from the same locality (and in close proximity), and 3 from Central Otago, The Remarkables Mts, 45°3'42"S, 168°48'40"E, 1829 m a.s.l., herbaceous snowbank, in soil, 19.ii.2014, coll. M. Minor (all on slides). Holotype and 4 paratypes kept in MNZTPT; 5 paratypes in MSPU.

Other material.

One ♀ identified in all details as Folsomia minorae sp. n. by A. Fjellberg (not seen by us): New Zealand, South Island (northern part), Avalanche Peak trail above Arthur Pass, 42°56'26"S, 171°33'29"E, forest litter, 23.i.2004, coll. A. Fjellberg.

Diagnosis.

Folsomia species with 5+5 ocelli; slender subapical organite of Ant.IV; clavate tibiotarsal hairs; outer teeth on claws; stout dens with few chaetae and a large mucro; and characteristic ‘3+2’ sensillary pattern of s-chaetae on Abd.V.

Description.

Body size of the only adult female 1.75 mm. Dark blue, appendages paler. Body cylindrical (Fig. 1). Abd.IV, V and VI clearly fused dorsally, Abd.IV and III well separated. Cuticle reticulated, with roundish polygons, the largest of which almost as large as chaetae bases. Ocelli 5+5, arranged in two groups: three anterior and two posterior. PAO slender, not constricted, almost as long as width of Ant I (0.8-1.0) and 1.1-1.4 as long as inner unguis length (Fig. 3). Maxillary outer lobe with four sublobal hairs, maxillary palp bifurcate. Labral formula as 4/5,5,4. Labium with five papillae ( A–E) and full set of ‘guards’, ‘guard’ e7 present, with three proximal, four basomedian, and five basolateral chaetae. Ventral side of head with 4+4 postlabial chaetae. Ant.I with two ventral s-chaetae (s) and three small basal ms-chaetae (bms), two dorsal and one ventral (Fig. 3), Ant.II with three bms and a latero-distal s, one of bms enlarged, Ant.III with one bms and with six distal s (including two lateral), without additional s-chaetae. S-chaetae on Ant.IV weakly differentiated. Apex of Ant.IV with two subapical ms (sms) both set at a distance from very long organite (org). Both sms of normal shape, organite with swelling in proximal part chili-shaped. The second subapical ms subequal to the first one, located more dorsally (Fig. 7). S-chaetae formula as common for the genus, 4,3/2,2,2,3,5 (s) and 1,0/1,0,0 (ms) (Fig. 2). Tergal s-chaetae much shorter than common chaetae and distinct. Medial s-chaetae on Th. II–Abd.III in mid-tergal position, on Abd. I–III between Mac1 and Mac2 (Fig. 2). Abd.V with five s-chaetae: three dorsal ones (al, accp1, accp2) long and slender, and two lateral short ( ‘3+2’ pattern) (Figs 2, 8, 12). Macrochaetae very long, stout and smooth, 1,1/3,3,3 in number, medial ones on Abd.V more than twice as long as dens (2.0-2.4) and 4.7-5.5 times longer than mucro. Foil chaetae at the tip of abdomen absent. Axial chaetotaxy of Th. II–Abd.III as 6 –8,6– 7/4,4,4. Thorax without ventral chaetae. Unguis stout, without inner teeth, with one (two on Leg III) outer and two large lateral teeth (Figs 4, 10, 11). The doubling of outer tooth on Unguis 3 well visible only in anterior position (Fig. 11). Empodial appendage about half as long as unguis (empodial appendage length: U3 = 0.46-0.53). Upper and lower subcoxae of Leg I, II, III with 1,1; 2-3,6; 4 –5,6– 9 chaetae. Tibiotarsi without additional chaetae on Leg I and II (21 chaetae), and with several additional chaetae on Leg III (more than 26 at whole). Tibiotarsal tenent chaetae clavate, long (1.3-1.6 longer than inner edge of U3), in number 1, 2, 2 on Leg I, II, III. VT with 4+4 laterodistal and 6 posterior chaetae, anteriorly without chaetae. Laterodistal chaetae arranged almost in a line, posterior chaetae in two rows, proximal (2) and distal (4). Tenaculum with 4+4 teeth and one chaeta. Basal tooth smaller than others (Fig. 9). Anterior furcal subcoxae with 8-9 chaetae, posterior one with four chaetae. Anterior side of manubrium with a pair of chaetae (Fig. 5). Posterior side of manubrium with 4+4 laterobasal and 4+4 on main part, without apical and lateral chaetae. To describe chaetae on main part the notation system of Fjellberg (2007) can be somewhat applied: chaetae M1, M2, pr and ml1 present (Fig. 9). Dens stout, with five anterior chaetae arranged as 1,1,3, the second single chaeta positioned more medially than the first (Figs 5, 6). Posterior side of dens almost smooth, with four chaetae of which one strong basal and three in central part (two of normal size and one small) (Fig. 9). Very large, chitinized, bidentate (Figs 6, 9). Ratio of manubrium: dens: mucro = 3.6-4.2: 2.0-2.4: 1.

Etymology.

The name is given after Maria Minor, who kindly provided some of the material on the new species.

Discussion.

To date eight species of Folsomia are known from New Zealand ( Greenslade 1994; 2012). In addition, three species, Folsomia parasitica Salmon, 1942, Folsomia novaezealandiae Salmon, 1943, and Folsomia lunata Salmon, 1943, were removed from the list as synonyms or were moved to the genus Cryptopygus (Bellinger et al. 2016). Among the valid species, five are blind, while others show different number of ocelli (8, 2 and 1, vs. 5 in Folsomia minorae sp. n.). Very little morphological data are available for endemic New Zealand Folsomia species ( Folsomia miradentata Salmon, 1943, Folsomia pusilla Salmon, 1944, Folsomia salmoni Stach, 1947, and Folsomia sedecimoculata Salmon, 1943). Particularly, figures of the furca are known only for Folsomia sedecimoculata and Folsomia pusilla . Both species show a more common structure of the dens (typical of the genus), which is slender and continuously narrowed, unlike in Folsomia minorae sp. n. Clavate tibiotarsal hairs were not figured or mentioned in descriptions of New Zealand forms (present in the new species). A comparison between Folsomia minorae sp. n. and Cryptopygus s.s. is given below.

Differentiating characters of the new species are: five ocelli, unique subapical organite of Ant.IV, clavate tibiotarsal hairs, presence of outer teeth on claws, stout dens with few chaetae, and a very large mucro. Well differentiated ‘3+2’ sensillary pattern of s-chaetae on Abd.V is also characteristic (see below). Three long and slender dorsal s-chaetae of Abd.V are found in species of several groups of Folsomia of the Holarctic (i.e. Folsomia penicula Bagnall, 1939, Folsomia quadrioculata (Tullberg, 1871) and Folsomia sensibilis Kseneman, 1936), which belong to either ‘3+2’ or ‘3+1+1’ patterns.

Distribution and ecology.

Folsomia minorae sp. n. is known from three localities in South Island, New Zealand. It is probably a species restricted to mountainous areas.