Entomobrya unostrigata Stach, 1930

Katz, Aron D., Giordano, Rosanna & Soto-Adames, Felipe, 2015, Taxonomic review and phylogenetic analysis of fifteen North American Entomobrya (Collembola, Entomobryidae), including four new species, ZooKeys 525, pp. 1-75 : 52-55

Taxon classification Animalia Collembola Entomobryidae

Entomobrya unostrigata Stach, 1930 Figs 2, 3C, 37, 38, 39

Description.

Body shape and color pattern. Body relatively robust and cylindrical. Color form largely monomorphic (Fig. 37): white, pale green or yellow background with purple or black pigment forming a thin medial longitudinal stripe from anterior margin of Th. 2 to posterior margin of Abd. 5; band ostensibly thicker on Th. 3 through Abd. 3. Patches of pigment forming a lateral line along margins of Th. 2 through Abd. 5, with variable spots of pigment present throughout. Abd. 5 and Abd. 6 usually lack dark pigment. Legs and furcula white and/or with light purple pigment. Antennae with light purple pigment.

Head. Apical bulb of 4th antennal segment usually bilobed. Long differentiated smooth setae on ventral side of 1st antennal segment ≈3 × short setae. Four prelabral setae ciliate. Ornamentation of the distal margin of the labral papillae with 2 seta or spine-like projections (Fig. 2). Lateral appendage of labial papilla E extending just past tip of papilla. Dorsal head chaetotaxy (Fig. 38A) with macrosetae An’ 0, A3a2, A3a3, A6, M3i, S’ 0, S6, Ps3, Pi1, Pa3, and Pm1i absent; S1, Pi2, and Pm1 usually present. Eyes G and H enlarged and similar in size to eyes C-F. Eye patch with 5 setae.

Thorax. Thoracic chaetotaxy well-developed and relatively stable. Th. 2 macrosetae a5, m1, m4, m4p, and m5 present (Fig. 38B); posterior macrosetae (series P) present. Th. 3 macrosetae a5e2, a5e3, m4, m5p, and a7 absent (Fig. 38C); P4 usually present. Both thoracic segments with many supplemental macrosetae on zone Pm (Figs 3C; 38B,C).

Legs. Trochanteral organ with triangular setal pattern and up to 21 setae.

Abdomen. Abdominal chaetotaxy highly developed and variable. Abd. 1 with 7-10 macrosetae (Fig. 38D). Abd. 2 macroseta a2, a3, m3, m3ep, m3e, m3ea, and m5 present (Fig. 38E); m3ei usually present. Abd. 3 macroseta a1, m3, am6, pm6, and p6 present (Fig. 38F). Abd.4 with 10-16 macrosetae present interior to bothriotricha T2 and T4 (Fig. 38G). Anterior half of Abd. 4 usually with 1 or 2 conspicuous rows of macrosetae. Apical mucronal tooth enlarged.

Remarks.

Entomobrya unostrigata can be easily diagnosed by color pattern, a thin medial longitudinal stripe from the anterior margin of Th. 2 to the posterior margin of Abd. 5, combined with the absence of macrosetae Th. 2 m2 and Abd. 3 a2 and the presence of macrosetae m5 on Th. 2 and a1 on Abd. 3 (see Table 2 for additional diagnostic characters). This species exhibits atypical morphology for a Nearctic Entomobrya . Eyes G and H are greatly enlarged and similar in size to eyes C-F, an uncommon trait unobserved in other Nearctic Entomobrya . Additionally, macrosetae usually form 2 rows on the anterior half of Abd. 4; a pattern shared with many Palearctic Entomobrya and also with members in the genus Homidia , but not with other Entomobrya treated here. Entomobrya unostrigata is a recently introduced species, now with a widespread Nearctic distribution ( Christiansen and Bellinger 1998), which may explain its distinction from other North American Entomobrya species included in the present study. The Entomobrya unostrigata specimens observed for this study have only two large seta or spine-like projections on each labral papillae (Fig. 2). However, multiple variations of the labral papillae have been reported ( Christiansen 1958b; Christiansen and Bellinger 1992; Christiansen and Bellinger 1998; Jordana 2012).

Distribution.

Nearctic, Palearctic, and Australia (Suppl. material 2: O).

Material examined.

USA: 2 on slides, Vermont, Chittenden Co., South Burlington, Vegetable garden on south side of Swift St. at intersection with Spear St. (44.4433,-73.1893), 3.viii.2003 (F. Soto-Adames); 1 on slide, Wisconsin, Dodge Co., Horicon Marsh National Wildlife Refuge, end of Dike Rd. (43.52736,-88.64381), 12.vi.2011, AK11-47.