Pseudosinella dungeri, Winkler & Mateos, 2018

Winkler, Daniel & Mateos, Eduardo, 2018, New species of Pseudosinella Schäffer, 1897 (Collembola, Entomobryidae) from Hungary, Zootaxa 4382 (2), pp. 347-366 : 357-361

Pseudosinella dungeri sp. nov.

Figs 21–40 , Tab 2

Type material. Holotype: female on slide (slide code: HNHM-collpr-802), Rigó Mount , Börzsöny Mountains, com. Pest ( Hungary), 310 m asl, N 47°46'32" E 18°56'12", from soil-litter, hand collecting, 11.iv.2017, leg. D. Winkler. Paratypes: two females (slide codes HNHM-collpr-803 and WD-coll-114) and one male (slide code: WDcoll-115) on slides; 8 specimens in alcohol (vial code HNHM-coll-954) ; same data as holotype. The holotype and one paratype are deposited in the Hungarian Natural History Museum, Budapest; two paratypes preserved in the first author’s collection at the University of Sopron, Faculty of Forestry , Sopron, Hungary .

Diagnosis. Small white species, eyes absent. Labial chaetotaxy M1M2rEL1L2, chaeta r strongly reduced. Dorsal macrochaetae formula R0R1s R1R2TP/10/0201+2. Abdominal tergite II chaetotaxy: pABq1q2. Abd. IV accessory chaeta s anteriorly to trichobothrial complex absent. Antennae and legs without scales. Unguis with one odd tooth, unguiculus outer lamella smooth.

Etymology. The species is named in honour of Prof. Dr. Wolfram Dunger, who made an extensive research on the Collembola fauna of the Börzsöny Mountauins, Hungary, describing from there seven species new to science and 30 species new for the Hungarian fauna.

Description. Holotype body length 0.79 mm (without head nor furca), paratypes 0.73–0.94 mm. Body without pigment ( Fig. 21 ). Antennae and legs without scales, manubrium ventrally with scales. Antennal length to head diagonal length ratio 1.4–1.6. Relation of antennal segments I–IV as 1: 1.8: 1.6: 3.2. Sensillary organ on ant. III with two leaf-like sensilla, two guard sensilla and a short rod ( Fig. 22 ). Apical bulb on ant. IV absent. Ciliated prelabral chaetae and smooth labral chaetae in typical arrangement and number 4/554 ( Fig. 23 ). Labral apical intrusion inverted U-shaped ( Fig. 23 ), labral edge with no differentiated papillae. Maxillary palp with two smooth lobal chaetae and three smooth sublobal chaetae. Lateral process (sensu Fjellberg 1999) of outer (E) labial papilla slightly curved, surpassing top of papilla ( Fig. 24 ).

Labial anterior row consists of 5 smooth chaetae (a1–a5); formula of basal row M1M2rEL1L2 with all chaetae ciliated except for strongly reduced smooth microchaeta r ( Fig. 25 ). Ventral cephalic grove with 4+4 ciliated chaetae ( Fig. 25 ). Among ciliated postlabial chaetae two vestigial smooth microchaetae also present ( Fig. 25 ).

Dorsal cephalic macrochaetae formula R0R1R2TP, with a short supplementary macrochaetae R1s between R0 and R1 ( Fig. 27 ). Following AMS notation system the dorsal head macrochaetae are: R0 = A0, R1s = A2s, R1 = A2, R2 = A3, T = S3, and P = Pa5. Maximum number of macrochaetae An on head 8+8 ( Fig. 27 ). Eyes absent.

Body macrochaetae 10/0201+2 ( Fig. 26 ). Dorsal chaetotaxy of th. II–III and abd. I as on Figs 28–30 . Mesothorax with p3 as macrochaeta. Anterolateral S-chaetae al and ms present. th. III without macrochaetae.

Anterolateral sensillum al present. Abd. I chaetae a3, a5 and a6 absent, lateral S-microchaeta (ms) present. Chaetotaxy of abd. II–III as in Figs 31–32 . Abd. II chaetotaxy between two dorso-medial trichobothria pABq1q2 using Gisin’s symbols ( Gisin 1967b); following Szeptycki (1979) system p = a2p, A = a2, B = m3, q1 = m3e and q2 = p4. Length of macrochaeta B equal to 2.5x macrochaetae A and m5. Macrochaeta B broad, A and especially m5 thinner. Abd. II chaeta ml absent. Abd. III with p6 as smooth mesochaeta. Abd. III chaeta d3 present with occasional bilateral asymmetry present–absent. S-microchaeta (ms) next to chaeta p5 present. Chaetotaxy and trichobothrial complex on abd. IV as in Figs 33–34 . Macrochaetae B5, B6, C1, D3, E2, E3, E4, F1 and F3 broader with broad socket, while D2, De3, E1, E4p, E4p2, F3p, T6 and T7 thinner with smaller socket. Abd. IV chaetae associated with two trichobotria fan-shaped. Accessory chaeta s associated with trichobotrium T2 absent. Apart from typical S-chaetae as and ps, two elongated dorsomedial sensilla also present. Abd. V with three S-chaetae typical for Pseudosinella .

Legs without scales. Trochanteral organ with up to 11 smooth spiny chaetae forming a V shape pattern ( Fig. 35 ). Unguis and unguiculus of claw III as in Fig. 36 . Unguis with paired basal teeth different in size at 48% from inner edge, and with unpaired tooth at 67% from inner edge. A small external tooth also present. Unguiculus lanceolate with smooth outer margin. Tibiotarsal tenent hair clavate, supraempodial chaeta smooth and acuminate. Ratio of supraempodial chaeta / unguiculus around 1.3.

Ventral tube without scales; 5+5 ciliated chaetae on anterior side and 6+6 ciliated chaetae on posterior side ( Fig. 37 ); lateral flap with a maximum of 2 smooth and 5 ciliated chaetae. Mucro as on Fig. 38 . Manubrial plate with 2 inner chaetae and 2 chaetae outer the 2 pseudopores ( Fig. 39 ).

Variability. Morphology of abd. IV chaeta E1 shows bilateral asymmetry (thin ciliated macrochaeta on one side and smooth mesochaeta on the other) in two specimens. In a single case, abd. IV chaeta C1p is duplicated on one side, showing different morphologies (both smooth and ciliated mesochaetae).

Ecology and distribution. The specimens of P. dungeri sp. nov. were found in low abundance in the upper soil layer of a sub-pannonic steppic grassland patch and in the edge of the pubescent oak forests around ( Fig. 40 ). Based on the known distribution and habitat associations, this new Pseudosinella species can be considered xerothermophilous.

Discussion. The only blind species with the same dorsal macrochaetae formula (R0R1R2TP/10/0201+2) is the cavernicolous Pseudosinella stygia Bonet, 1931 ( Table 2). There is a marked difference, however, regarding the macrochaetae of abd. II. While P. dungeri sp. nov. has A and B as macrochaetae, P. stygia is one of the rare species with Q1 developed as macrochaeta. The new species differs from P. stygia also by the labial chaetae. Except for the vestigial smooth microchaeta r, all chaetae are ciliated in P. dungeri sp. nov., while all chaetae, with a rare exception of M1 ciliated, are smooth in P. stygia . As reported by Gisin & Gama (1972) in the redescription of P. stygia , abd. II microchaeta p and abd. IV supplementary chaeta s could not be observed neither in the type material nor in the topotypic specimen, however, their possible presence was not excluded by the authors considering the condition of the material examined. From the mentioned chaetae only abd. II p is present in P. dungeri sp. nov. Differences between the two species can be observed also in the morphology of the foot complex. The unguis of P. stygia is rather elongated while it is relatively short in the new species. The two proximal teeth are close to the ungual base in P. stygia while they are situated at around the half of the unguis length in P. dungeri sp. nov. The very short unpaired internal tooth is situated at around 40% distance from the unguis base in P. stygia , while it is well developed and positioned at 2/3rds of distance from the unguis base in the new species. Tenent hair is clavate in the new species and acuminate in P. stygia . The colour of P. dungeri sp. nov. is white, while scattered pigment granules are covering the whole surface of body of P. stygia . Regarding habitat characteristics, P. dungeri sp. nov. inhabits xerophil grasslands and forest edges, while P. stygia is a rare troglobiont species confined to the cave ‘Cueva del Castillo’ in Spain. The new species has chaeta p6 on abd. III as smooth mesochaeta ( Fig. 32 ) while, usually, this is a ciliated macrochaeta in Pseudosinella species.

Figures

FIGURE 21. Pseudosinella dungeri sp. nov. (habitus)

FIGURE 22–25. Pseudosinella dungeri sp. nov.: 22, ant. III sensillar organ; 23, labrum; 24, labial papilla E with lateral process; 25, labial triangle (right side) and ventral cephalic groove with labial and postlabial chaetotaxy.

FIGURE 26–27. Pseudosinella dungeri sp. nov.: 26, distribution pattern of dorsal macrochaetae (filled circles), trichobotria (lines) and pseudopore (Ø); 27, dorsal head chaetotaxy, broad black circles—long ciliated macrochaetae, small black circlesshort ciliated macrochaetae (nomenclature “RST”—right side, normal letters, nomenclature “AMS” – left side, italicized letters).

FIGURE 28–30. Pseudosinella dungeri sp. nov.: 28, th. II dorsal chaetotaxy (left side), broad black circle—broad ciliated macrochaeta, psp—pseudopore; 29, th. III dorsal chaetotaxy (left side), psp—pseudopore; 30, abd. I dorsal chaetotaxy (left side), psp—pseudopore.

FIGURE 31–32. Pseudosinella dungeri sp. nov.: 31, abd. II complete chaetotaxy (left side), broad black circles—broad ciliated macrochaetae, psp—pseudopore; 32, abd. III complete chaetotaxy (left side), broad black circles—broad ciliated macrochaetae, small black circles—thin ciliated macrochaetae, psp—pseudopore.

FIGURE 33–34. Pseudosinella dungeri sp. nov.: 33, abd. IV chaetotaxy, broad black circles—broad ciliated macrochaetae, small black circles—thin ciliated macrochaetae, open circles—mesochaetae, triangles—fan-shaped chaetae, x—trichobotria, psp—pseudopore; 34, abd.IV trichobothrial complex.

FIGURE 35–39. Pseudosinella dungeri sp. nov.: 35, trochanteral organ; 36, leg III unguis and unguiculus; 37, ventral tube anterior view (left side) and posterior view (right side), circles—ciliated chaetae; 38, mucro and apical part of dens; 39, manubrial plate, black circles—ciliated macrochaetae, Ø—pseudopore.

FIGURE 40. Type locality (Börzsöny Mountains:Rigó Mount) of Pseudosinella dungeri sp. nov.