Entomobrya clitellaria Guthrie, 1903

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 : 27

Taxon classification Animalia Collembola Entomobryidae

Entomobrya clitellaria Guthrie, 1903 Figs 2, 17, 18, 39

Description.

Body shape and color pattern. Body dorso-ventrally flattened. Dimorphic color pattern, unrelated to sex (Fig. 17): dark blue, purple, or black pigment covers Th. 3 and Abd. 1-3. Abd. 4 usually white, yellow, or orange with variable levels of pigment ranging from an irregular medial transverse band, randomly distributed irregular patches, or completely pigmented. Th. 2 always white, with a dark band along the anterior margin; medial area of Th. 2 almost transparent in some specimens and internal fat bodies can be observed through the cuticle under a dissecting microscope. Darker specimens with head mostly covered by dark pigment. Antennae usually entirely covered by purple pigment, but some specimens have a mixture of orange, brown, and purple coloration.

Head. Apical bulb of 4th antennal segment usually simple, sometimes bilobed. Long differentiated smooth setae on ventral side of 1st antennal segment ≈3 × short setae. Prelabral setae ciliate. Ornamentation of the distal margin of the labral papillae with a single seta or spine-like projection (Fig. 2). Lateral appendage of labial papilla E slightly curved, relatively thin, nearly reaching tip of papilla. Labial triangle in one individual with 1 small supplementary ciliate microsetae internal to M1. Dorsal head chaetotaxy (Fig. 18A) with macrosetae An’ 0, A3a3, M3i, S’ 0, S6, and Ps3 always absent; An3a2 usually present; Pi1, Pm1, Pm1i, and Pp2 present or absent. Eyes G and H small and subequal. Eye patch with 5 setae.

Thorax. Thoracic chaetotaxywell-developed, with some slight variation. Th. 2 macrosetae m4i3 absent, m1i usually present (Fig. 18B). Th. 3 macrosetae a5e3, m4, m5p, and a7 absent (Fig. 18C). Both thoracic segments with many supplemental macrosetae in zone Pm (18B,C).

Legs. Trochanteral organ with triangular setal pattern and up to 26 setae. Unguis with 4 inner teeth; basal teeth located approximately middle of inner claw length.

Abdomen. Abdominal chaetotaxy highly developed. Abd. 1 with 8-13 macrosetae (Fig. 18D). Abd. 2 macroseta a2, a3, m3, m3ep, m3e, and m5 present; M3ei and M3ea usually present and M3eai usually absent (Fig. 18E). Abd. 3 macrosetae a2, a3, m3, am6, pm6, and p6 present; a1 always absent (Fig. 18F). Abd. 4 chaetotaxy stable, with 7 macrosetae between bothriotrichal complexes (Fig. 18G). Mucronal teeth subequal.

Remarks.

Entomobrya clitellaria can be distinguished by the combination of color pattern, absence of macroseta head S’ 0 and Abd. 3 a1 and presence of head Ps5, Th. 2 m5, Abd. 2 m3ep, and Abd. 3 a2 (see Table 2 for additional diagnostic characters). This species has a relatively conspicuous and diagnostic color pattern, but may be confused with the male Entomobrya atrocincta . However, there are obvious differences in their morphology outlined in Table 3. Christiansen and Bellinger (1998) described six different color forms, but after extensive examination of material collected for this study, it was determined that many (but not all) of the color forms they described were most likely variants within a continuous gradient of color pattern variation, without clear genetic isolation ( Katz et al. 2015). The two lighter forms (labeled E and F in Christiansen and Bellinger 1998) proved to be elusive and were not collected during this study.

This species is closely related to Entomobrya jubata sp. n., but can be easily separated by color pattern, chaetotaxy, and morphology of the labral papillae. The absence of head macrosetae S’ 0 and the presence of head macrosetae Ps5 separate Entomobrya clitellaria from Entomobrya jubata sp. n. Labral papillae morphology also differs between these species: Entomobrya jubata sp. n. has two or three seta or spine-like projection on each papilla, while Entomobrya clitellaria only has one seta or spine-like projection per papilla (Fig. 2).

Distribution.

Endemic to North America (Suppl. material 2: E).

Material examined.

USA: 1 on slide, Florida, Taylor Co., Econfina State Park (30.0656,-83.91066), under bark, 9.viii.2011, AK11-116; 1 in vial, Illinois, Champaign Co., Urbana, Brownfield Woods (40.14462,-88.16543), on bushes and low-lying shrubs, 7.vii.2011, AK11-60; 1 on slide, Illinois, Champaign Co., Urbana, Brownfield Woods (40.14391,-88.16468), under bark, 10.ix.2009 (F. Soto-Adames); 1 in vial, Illinois, Coles Co., Fox Ridge State Park (39.40248,-88.14893), under bark, 15.vii.2011 (A. Katz & F. Soto-Adames), AK11-81; 3 on slides, 20 in vials, Illinois, Jasper Co., Sam Parr State Fish and Wildlife Area (39.03275,-88.12474), under bark, 15.vii.2011 (A. Katz & F. Soto-Adames), AK11-73, AK11-74 & AK11-75; 1 in vial, Illinois, Jasper Co., Sam Parr State Fish and Wildlife Area (39.03275,-88.12474), in leaf litter, 15.vii.2011 (A. Katz & F. Soto-Adames), AK11-77; 1 on slide, 1 in vial, Illinois, Jo Davies Co., Princess Mine 1 (42.30565,-90.39740), under bark, 26.viii.2011, AK11-142; 1 in vial, Illinois, Jo Davies Co., S Blanding Rd, Stevenson Property (42.29895,-90.36967), under bark, 27.viii.2011, AK11-148; 1 on slide, Illinois, Kankakee Co., Kankakee River State Park (41.19482,-87.96875), from bird nest, 10.iv.2011, AK11-6; 4 on slides, Illinois, Monroe Co., Bat Sump Cave, Berlese of bark, 1-3.xi.2009 (S. Taylor & F. Soto-Adames), sjt09-130; 4 on slides, 50+ in vial, Illinois, Piatt Co., Lodge County Forest Preserve Park (40.06709,-88.56596), dead logs, cavity in tree, and under bark, 23.vii.2011, AK11-100; 2 on slides, 10 in vial, Illinois, Pope Co., Bell Smith Springs (37.51927,-88.65738), leaf litter, 24.ix.2011, AK11-166; 2 on slides, Illinois, Vermilion Co., Kickapoo State Park (40.16576,-87.74746), on rotten log, 30.xi.1989 (F. Soto-Adames); 1 in vial, Illinois, Vermilion Co., Kennekuk Cover County Park, Windfall Prairie Nature Preserve (40.20995,-87.74181), aspirated from bushes, 16.vi.2011 (A. Katz & F. Soto-Adames), AK11-59; 1 in vial, Michigan, Ingham Co., Michigan State University, Baker Wdlt. (42.66527,-84.36264) under bark of standing dead pine, 24.vii.2008 (E. C. Bernard), BW-11; 1 on slide, 3in vial, Michigan, St. Clair Co., Algonac State Park (42.65447,-82.52430), under bark of recently fallen maple, 25.vii.2008 (E. C. Bernard), ASP-15; 1 on slide, West Virginia, Monongalia Co., Tyrone (39.62746,-79.86567), under collected on the lower branches of eastern hemlock, 19.vii.2005 (R. M. Turcotte), ID#44-GE-21-5-4-A.