Stenaphorura shaconage, Bernard, Ernest C., 2016

Bernard, Ernest C., 2016, Two new genera and five new species of Tullbergiidae (Collembola) from the southern Appalachian Mountains of North America, with redescription of Tullbergia clavata Mills, Zootaxa 4162 (3), pp. 451-478 : 467-471

Stenaphorura shaconage n. sp.

Figs 10‒12

Material examined. Holotype female, North Carolina, Swain County, Great Smoky Mountains National Park ( GSMNP), Ravensford area , leaf litter in mixed deciduous upland forest, near pitfall 35, N669200.106, E722181.572, 28 December 2001, E.C. Bernard and A. Mayor, colls . Paratypes: two females and one male on slides, three specimens in ethanol, same data as holotype; one male and one female on slides, two in ethanol , same data as holotype except near pitfall 37, N669182.193, E722188.803; one female on slide, Tennessee, Cocke County, GSMNP, Cosby area near DLIA house, sample RTA-5-A1S, UTMe 299905, UTMn 3962097, elev. 1183 m, 3 July 2005, R.T. & S.H. Allen, colls.; two females on slides , Tennessee, Blount County, GSMNP, soil and organic debris at mouth of Gregory Cave, N35°36’ W83°48’, 15 October 1998, W. Reeves, coll. ; one male, Tennessee, Blount County, GSMNP, trail above Laurel Falls , no other data.

Description. White; length 674‒1034 µm (mean 834 µm); antennae shorter than head, dorsal setae differentiated as microsetae, mesosetae and macrosetae. Pseudocellar formula 11/122/22221, occasionally a lateral pso missing from one side; large dorsal body pseudocelli primarily Type III (crescentic) ( Figs 11 D, E), sometimes apparently structureless; small lateral pseudocelli with uniform surface, internal structure not observed ( Fig. 11 C). Pseudocelli typically partly surrounded by coalesced granules forming flattened, linear structures ( Figs 11 C‒E). Dorsal pseudocelli of Abd. IV each with prominent accessory tubercle ( Fig. 11 D). Pseudopores absent. Abd. VI with two pairs of anal spines and pair of protuberances anterior to proximal spines ( Fig. 11 B). Terminal anal spines twice length of lateral spines, length 1.5‒1.7× that of posterior unguis.

Granules on dorsum of head of variable size (diameter 1.4‒2.2 µm, mean 1.7 µm), evenly distributed, round. Thoracic nota and Abd. I‒II with strong mid-dorsal band of 12‒15 longitudinal rows of large granules (diameter 2.2‒2.7 µm, mean 2.6 µm), subdorsal fields with smaller granules (diameter 1.2‒1.6 µm, mean 1.4 µm). Abd. III‒V granulation not in longitudinal rows. Posterior region of all segments except pronotum and Abd. VI with up to 15 distinct transverse rows of granules between the dorsal pseudocelli ( Figs 11 B, E). On Abd. VI dorsal granules large, of similar size, 2.5‒3.0 µm (mean = 2.7 µm).

Labial palpus with papillae A, B, C and D ( Fig. 10 G), spines not thickened or rounded, spine of C shorter than others; a1 guard seta a minute knob, two slender guard setae associated with papilla B, two associated with papilla D, other guard setae if present not seen. Hypostomal seta H and guard setae h1 and h2 normal. Outer lobe of maxilla without sublobal hairs, terminal seta long and robust ( Fig. 10 H). Mandible with four apical teeth. Two prelabral setae. Labral formula 3-4-2, distal setae and middle setae of middle row much stouter and longer than other setae. Postantennal organ variable in size, consisting of 32‒52 oval vesicles in two rows, with one or more small, round vesicles between or within the rows ( Figs 10 D, 11A).

Ant. I with 7 setae, Ant. II with 11 setae. Dorsally, Ant. IV with seven prominent curved sensilla and two equally prominent but straight sensilliform setae ( Fig. 10 E); other dorsal setae thin but sensilliform with rounded tips; microsensillum a short rod set in a groove; organite oval; apical bulb spherical, granulate. Ventral face of Ant. IV with two arcuate sensilla and four straight, strong, sensilliform distal setae, one of which is much longer than the other three; mid-ventral region with seven short setae, most with rounded tips ( Fig. 10 F) Ant. III dorsal sense organ with three large sense clubs and two sense rods partially covered by integumentary folds, and four guard setae; sense rods minutely lobed along apex ( Fig. 10 E). Ant. III ventral sense club present; all Ant. III setae pointed.

All leg setae pointed. Each femur with 8 setae, fore, middle and hind tibiotarsi with 12, 12, 11 setae, respectively ( Fig. 10 I). Unguis stout, without teeth or tunica-like expansion; unguiculus an irregular knob. Tenacular region on Abd. III venter indicated by ungranulated transverse oval between m1 setae; furcal region on Abd. IV indicated by ungranulated T-shaped region between a1 and m1 setae ( Figs 10 C, 12B).

Head strongly heterochaetotic ( Fig. 10 A), medial microseta anterior to seta a0; all d-setae minute, d2 slightly longer than others; seta sd5 long; sd4, v2, c5, g2, p1, p2 and p5 macrosetae, other setae mesosetae or microsetae. Seta v1 present, v2 absent. Six setae between posterior cephalic pseudocelli; p1 and p2 of equal length. Pronotum with 8 setae. Mesonotum and metanotum each with m-row consisting of m1, m3, m4 and m5; setae a3, m4 and p5 macrosetae; seta p1 absent on mesonotum, present on metanotum, where p2 is longer than p1; microsensillum in shallow pit near long sensory seta ( Fig. 10 B). Abdominal segment I with seta m4, Abd. II‒IV with six a-setae and with m4 and m5; p2 longer than p1 on Abd. II and III, p2 shorter than p1 on Abd. IV and displaced anteriorly. On Abd. V seta p1 absent, all setae as macrosetae except a1 and a3 ( Fig. 11 E). Abd. VI with two unpaired medial setae.

Ventrally, head with three pairs of medial setae. Mesosternum and metasternum each with two setae. Ventral tube with 4+4 setae on valves and 2+2 setae on base. Ventral abdominal setae frequently arranged asymmetrically. Sterna of Abd. II‒IV each with 4 a-setae, medial m-seta (m0) and postero-lateral sensilliform seta. Sternum of Abd. V with two rows of setae anterior to genital aperture, second row with medial seta; setae lateral to aperture sensilliform. Pleural regions of Abd. II‒IV each with anterior and posterior sensilliform setae, Abd. V with one pleural sensilliform seta ( Fig. 10 C). Anterior lip of genital aperture with two setae. Male genital plate ( Figs 12 C, D) slightly recessed, with 16 setae; six most anterior setae stout, bifurcate, overlapping six smaller, pointed setae; aperture flanked posteriorly by two wavy setulae; granule-free zones each with one seta in posterior area. Anal lobes of Abd. VI with complete complement of setae. Pleural regions of Abd. II‒IV each with anterior and posterior blunt sensilliform setae.

Etymology. The specific name, shaconage , is a Cherokee word meaning “place (or land) of blue smoke”, referring to the hazy bluish appearance of the southern Appalachian Mountains and peaks along the Blue Ridge Parkway, where most of the specimens were collected.

Remarks. Stenaphorura shaconage n. sp. is the first member of its genus reported from North America. The presence of two pairs of pseudocelli on several segments distinguishes it from most other members of the genus and places it outside the limits of Stenaphorura as defined by Rusek (2010) and Dunger & Schlitt (2011). Some specimens of S. metaparisi ( Traser & Weiner, 1999) have two pairs of pseudocelli on the mesonotum, metanotum and Abd. IV ( Traser & Weiner 1999), but S. shaconage n. sp. has two pairs on the mesonotum, metanotum and Abd. I‒IV. Stenaphorura marionae Thibaud, 2002 has the same pso formula as S. shaconage n. sp. but possesses only two dorsal sense clubs on Ant. III and thus may not even be a true Stenaphorura , for which the presence of three dorsal sense clubs is a defining characteristic ( Dunger & Schlitt 2011). Fissuraphorura gisini ( Selga, 1963) also has the same pso formula and has three Ant. III sense clubs, but differs in numerous features of the postantennal organ and chaetotaxy ( Luciañez & Simon 1992, Selga 1963).

The chaetotaxy and most other characters of S. shaconage are identical to those of Tullbergia nearctica n. sp. The species are easily separated by the number of anal spines. The dorsal granules on Abd. VI of S. shaconage n. sp. are of uniform size and well-separated ( Fig. 11 B), whereas those of T. nearctica n. sp. are of two size ranges (smaller anteriorly, larger posteriorly) and densely packed ( Fig. 14 E).

The male genital plate, with six stout, bifurcate setae and ten pointed setae, appears to be quite distinctive, but this structure has previously been described only for S. quadrispina Börner, 1901 . That species has six pointed setae on the anterior margin and two lateral setae ( Stach 1954). Some of the differences may be due to interpretation of what constitutes the genital plate, but they suggest that the male genital plate needs to be carefully described when it is encountered. Most Stenaphorura and Dinaphorura spp. are known to have males and the characters of the plate could have species-specific taxonomic value.

Figures

FIGURE 10. Stenaphorura shaconage n. sp. A) Head, dorsal view. B) Thorax and abdomen, dorsal view. C) Abdominal segments II ‒ VI, ventral view. D) Postantennal organ. E) Third and fourth antennal segments, dorsal view. F) Third and fourth antennal segments, ventral view. G) Labial palp. H) Outer lobe of maxilla. I) Middle leg. Scales: A, 100 µm; B, C, 100 µm; D, 10 µm; E ‒ I, 10 µm.

FIGURE 11. Stenaphorura shaconage n. sp. A) Postantennal organ. B) Fifth and sixth abdominal segments, lateral view. Arrow indicates anterolateral swelling. C) Dorsal (d) and lateral (l) pseudocelli, right side, Abd. III. D) Dorsal pseudocelli of Abd. IV. Arrows indicate associated tubercles. E) Fifth abdominal segment, right side, showing blunt and pointed setae and crescentic pseudocellus. Scales: A, 10 µm; B, 50 µm; C ‒ E, 20 µm.

FIGURE 12. Stenaphorura shaconage n. sp. A) Mesonotum, dorsal view. B) Venter of Abd. III ‒ IV showing primary granulation in tenacular (t) and furcal (f) regions. C) Venter of Abd. V, male. D) Male genital plate. S: sensilliform seta. Scales: A, C, D, 20 µm; B, 10 µm.

FIGURE 14. Tullbergia nearctica n. sp. A, B) Postantennal organs. C) Labrum. D) Third thoracic and first abdominal segments, showing mid-dorsal band of larger granules. E) Abdominal segments V and VI, dorsal view. Top inset, seta p 3 of Abd. V; bottom inset, seta a 2 of Abd. VI. F) Venter of Abd. VI. Setae a 5 and p 5 not in plane of view. Scales: A ‒ C, 10 µm; D ‒ F, 20 µm.