A new species of Pseudosinella Schäffer, 1897 (Collembola, Entomobryidae) from Hungary and Romania, with redescription of the related species Pseudosinellahuetheri Stomp, 1971

Abstract A new species of the genus Pseudosinella Schäffer, 1897 from Hungary and Romania is described and illustrated. Pseudosinellahartneraesp. nov. belongs to the group with 5+5 eyes, and can be identified by its unique labial chaetotaxy (M1m2rel1L2) within this group. Pseudosinellahuetheri Stomp, 1971, the closest related species sharing the same dorsal macrochaetae formula (R0R1R2001/00/0101+2), is also redescribed here based on the holotype. Comparative analysis between the two species and among other related species is provided.

As a part of soil biodiversity surveys in Hungary, the Bátorliget Pasture Nature Conservation Area was revisited in 2017. Among the collected Collembola material, a new species of Pseudosinella Schäffer, 1897 was discovered and is described in the present paper. Around the same time, Collembola samplings were carried out in Romania Mohoş Nature Reserve, from where the same Pseudosinella species was also found. The genus was previously represented by 17 species in Hungary (Dányi and Traser 2008;Winkler and Mateos 2018) and 24 species in Romania (Fiera 2013). However, its richness is probably underestimated and doubtless destined to increase with further taxonomic efforts in both countries.
The new species belongs to the group of species with 5+5 eyes. With the help of the computer assisted Delta identification key using the combination of chaetotaxic and other characters, originally designed by Christiansen et al. (1990) and regularly updated by Jordana et al. (2021), Pseudosinella huetheri Stomp, 1971 was found to be its closest related species. Therefore, on this occasion, Pseudosinella huetheri was also examined and redescribed from the holotype preserved in the Natural History Museum of Geneva (Switzerland).

Material and methods
In October 2017, soil samplings were carried out in the Bátorliget Pasture Nature Conservation Area (East Hungary). A month later, soil mesofauna samplings were carried out also in Romania, around St. Ana Lake (Mohoş Nature Reserve). Springtails were extracted from the hand collected litter and soil samples within 14 days using a modified Berlese-Tullgren apparatus (without light or heating devices). The specimens were cleared using Nesbitt fluid and then mounted on permanent slides in Hoyer's medium. The slides were examined under a Leica DM2500 LED microscope with conventional bright light and phase contrast.
Abbreviations used in text and figures are:
Body. Body dorsal macrochaetae from Th II to Abd IV 00/0101+2. Mesothorax without macrochaetae. Two anterolateral S-chaetae (al and ms) present. Th III without Mac, anterolateral sensillum al present. Abd I with lateral S-microchaeta (ms). Chaetotaxy of Abd II-III as in Fig. 3A, B. Abd II chaetotaxy between two dorsomedial trichobothria paBq 1 q 2 using Gisin's symbols (Gisin 1967); following Szeptycki's (1979) notation p=a 2 p, a=a 2 , B=m 3 , q 1 =m 3 e and q 2 =p 4 . Chaeta a as ciliated mic. Abd III chaeta d 3 present. Chaetotaxy and trichobothrial complex on Abd IV as in Fig. 4A, B. Mac B 5 , B 6 , C 1 , E 2 , E 3 , F 1 and F 2 broader with broad sockets, D 2 , D 3 , De 3 , E 4 , E 4 p, E 4 p 2 , F 3 , F 3 p, Fe 4 , Fe 5 , T 6 and T 7 thinner with smaller sockets. Abd IV with five fan-shaped chaetae (D 1 , a, m, p e and p i ) associated with two trichobothria. Accessory chaeta s, associated with trichobotrium T 2 , absent. Nine S-chaetae (as, ps, and seven long dorsal S-chaetae) present. Dorsal chaetotaxy of Abd V as in Fig. 4C. Three S-chaetae (as, acc.p4 and acc.p5) typical for Pseudosinella present. Legs without scales. Trochanteral organ with up to 12 smooth spiny chaetae forming a V-shaped pattern (Fig. 5A). Unguis and unguiculus as in Fig. 5B. Unguis with subequal paired basal teeth at 35% from inner edge, and with a median unpaired inner tooth at 60% from inner edge, apical tooth absent. Outer side with paired lateral teeth and a short external tooth. Unguiculus lanceolate, external lamella smooth. Tibiotarsal tenent hair clavate, supraempodial chaeta on tibiotarsus III smooth and acuminate. Ratio of supraempodial chaeta / unguiculus around 0.9. Ventral tube without scales; with 6+6 subequal ciliated chaetae on anterior side and 4+4 subequal ciliated chaetae on posterior side; lateral flap with 1 ciliated and a maximum of 6 smooth chaetae (Fig.  5C). Manubrium ventrally with scales and 2+2 terminal ciliated chaetae. Manubrial plate with 2 larger inner chaetae and 2 chaetae external to the 2 pseudopores (Fig.  5D). Length of not ringed terminal dens about 4 times the length of mucro. Mucro with distal tooth equal to anteapical one; basal spine reaching tip of anteapical tooth (Fig. 5E). Ratio manubrium/dens/mucro as 16:15:1. Ecology and distribution. The type locality (Bátorliget Pasture Nature Conservation Area, Szabolcs-Szatmár-Bereg county, Hungary) of Pseudosinella hartnerae sp. nov. is a special relict mire and forest area with high biodiversity. The new species was collected from the upper layer and litter of a forest clearing with pioneer vegetation including silver birch (Betula pendula) trees. Specimens in Romania were collected from litter in the surrounding forest of the volcanic lake Saint Ana, and from peat mosses in the nearby Mohoș bog. Both Romanian sites are located in the Mohoş Nature Reserve, Harghita County. This new Pseudosinella is a phytodetriticolous, bryophilous and hygrophilous species.
Etymology. The name of the new species is dedicated to former zoologist colleague and friend Dr. Anna Fenyősiné Hartner , an excellent specialist in myrmecology.
Ecology and distribution. Pseudosinella huetheri was described from Luxembourg, from a beech forest near Berdorf (Stomp 1971). The original description reported the species also from Germany and Switzerland. Later, the species was found in Austria (Bretschko and Christian 1989), France (Ponge 2004) and Slovakia (Raschmanová et al. 2008). Dányi et al. (2006) collected a species close to P. huetheri in Romania, listed as "Pseudosinella cf. huetheri", but without any differential character being mentioned.