Entomobrya cf. quinquelineata Boerner , 1901

Winkler, Daniel, Sternalski, Jakub, Onodi, Gabor, Szigeti, Nora, Florian, Norbert & Danyi, Laszlo, 2023, Investigation on the true identity of Entomobrya nigriventris Stach, 1929 (Collembola, Entomobryidae) with the description of a new species, ZooKeys 1185, pp. 321-353 : 321

Entomobrya cf. quinquelineata Boerner, 1901

Figs 12 , 13

Material.

Five ♂♂ on two slides (Nr. HNHM-collpr-922 to Nr. HNHM-coll-923) preserved at HNHM, Hungary, Szarhalmi forest , Sopron, com. Győr-Moson-Sop-ron, 47°41'54"N, 16°38'22"E, 214 m above sea level. D-vac sample, 13 Oct. 2018, leg. D. Winkler.

Description.

Habitus. Adult body length 1.73-2.05 mm excluding antennae. Body ground colour pale yellow or yellowish brown, with five dark longitudinal stripes: the dorsal and two dorsolateral from Th II to posterior margin of Abd III, lateral ones from Th II to posterior margin of Abd IV. Dorsal and dorsolateral stripes may widen here and there, especially on Th III-Abd III. Abd IV with some irregular patches, anterior part often entirely dark (Fig. 12A ). Ventral body partly or entirely dark in most adult specimens (Fig. 12B ). Violet pigments on antennae with increasing intensity from base to apex of segments.

Head. 8+8 eyes, GH smaller than EF (Fig. 13A ). Interocular chaetotaxy with five chaetae (s, t, p, q, r). Antennae length 1.11-1.20 mm. Antennal length to head diagonal length ratio 2.58-2.95 (n = 5). Relation of antennal joints I-IV as 1: 2.1-2.3: 1.5-2.0: 1.7-2.5 (n = 5). Ant IV with bilobated apical bulb. Ant III sensillary organ composed of two sensory rods partially behind a cuticular fold, guarded by three short sensilla. Arrangement of chaetae on labrum 4/554, prelabral chaetae ciliated, posterior, median and anterior labral chaetae smooth. Labrum with four rounded labral papillae (Fig. 13B ). Outer maxillary palp with two smooth chaetae and three smooth sublobal chaetae. Curved lateral process on labial papilla E not reaching apex of papilla. Labium chaetotaxy formed by five smooth “a” chaetae and, in basal row, by ciliated chaetae M, R, E, L1, and L2 with R smaller than other chaetae (ratio of R/M ~0.6).

Body. Ratio of Abd IV/III length 3.77-4.54 (n = 5). Trochanteral organ with up to 22 spine-like chaetae (Fig. 13C ). Unguis and unguiculus of claw III as in Fig. 13D . Unguis with sub-equal paired basal teeth at 59% from the inner edge, and with two more unpaired teeth at 80% and 92% from inner edge, respectively. Paired lateral teeth intermediate at level slightly below the paired internal teeth. Unpaired dorsal tooth basal, located approximately at one-quarter of distance from base. A small pretarsal chaeta present on both anterior and posterior surfaces. Unguiculus lanceolate, outer lamella smooth. Tibiotarsal tenent hair clavate, longer than claw. Ratio of smooth terminal chaeta / unguiculus ~ 1. Ventral tube anteriorly with 11+11 chaetae (4+4 ciliated Mac and 7+7 finely ciliated mic) and with 4+4 thin, finely ciliated chaetae on posterior side; lateral flap with 3 ciliated and 6 smooth chaetae. Manubrial plate with four chaetae and two pseudopores. Length of not ringed terminal dens ~ 3 × the length of mucro. Mucro with distal tooth equal to anteapical; basal spine just reaching tip of anteapical tooth.

Macrochaetotaxy (Fig. 13A,E-H ). Simplified Mac formula: 3-1-0-2(3)-2/2-3/2-2/1-2-1/0-4(5)-4-2-2. Head (Fig. 13A ): H1 area with three Mac (An2, An3a1, An3); H2 area with one Mac (A5); H3 area without Mac; H4 area with 3 Mac (S1, S3, S4i); H5 area with two Mac (Ps2 and Ps5). Mesothorax (Fig. 13E ): area T1 with two Mac (m1 and m2i); T2 with three Mac (a5, m4 and m4i). Abdomen: Abd II (Fig. 13F ) area A1 with two Mac (a2 and a3); area A2 also with two Mac (m3 and m3e); Abd III (Fig. 13G ) area A3 with one Mac (a1); area A4 with two Mac (a2 and a3), and one Mac (m3) on A5; Abd IV (Fig. 13H ) area without Mac; area A7 with 4-5 Mac (A3p, Ae3, C1, E1 always present, B2 present or absent); area A8 with four Mac (A4a, Ae4, B4, C2a); area A9 with two Mac (A5 and B5); and area A10 with two Mac (A6 and B6). Sensillar formula from Th II to Abd V: 2,2/1,2,2,9,3; microsensillar formula from Th II to Abd III: 1,0/1,0,1.

Ecology.

The specimens were collected in xerophilous dolomite-steppe meadow plant associations.

Remarks.

The specimens collected in Hungary differ in their colour pattern from the original form described by Börner (1901), which Stach (1963) later named f. Entomobrya principalis , and in which the longitudinal central and dorsolateral stripes run uninterrupted to the posterior part of Abd IV. The similarity in the colour pattern can be discovered mostly with individuals from Switzerland, Holland, or Lithuania, presented in the species redescription ( Baquero and Jordana 2008), in which the longitudinal stripes are interrupted on Abd IV. Nevertheless, the occurrence of a dark ventral side has not been described in this species until now, although it is not rare in some populations.

In their comprehensive redescription of E. quinquelineata based on European materials, Baquero and Jordana (2008) provided the essential dorsal macrochaetae distribution and information on its variability. The dorsal macrochaetotaxy of the Hungarian specimens is fairly consistent with the previous redescriptions ( Baquero and Jordana 2008; Jordana 2012). Differences include the presence of Mac S1 in the H4 area of the head. The number of macrochaetae in this area is usually two. However, in a specimen from Switzerland, the presence of a third macrochaeta was hinted at but marked as questionable because of the poor condition of the slide examined ( Baquero and Jordana 2008).

Although the dorsal colour pattern suggests that we found a population of E. quinquelineata , considering the abovementioned difference in head chaetotaxy, we identify it as E. cf. quinquelineata .

Figures

Figure 12. Entomobrya cf. Entomobrya quinquelineata. Habitus A dorsolateral view B ventral view (same specimen). Scale bar: 0.5 mm.

Figure 13. Entomobrya cf. quinquelineata A head chaetotaxy B labral papillae C trochanteral organ D unguis and unguiculus of leg III E Th II dorsal macrochaetotaxy F Abd II dorsal macrochaetotaxy G Abd III dorsal macrochaetotaxy H Abd IV dorsal macrochaetotaxy. Abbreviations: Abd = abdominal tergite; Th = thoracic tergite. Scale bars: 0.03 mm (A-C); 0.02 mm (D); 0.05 mm (E-H).