Tullbergia nearctica, 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 : 472-474

Tullbergia nearctica n. sp.

Figs 13 , 14

Material examined. Holotype female and two paratype females on slides, North Carolina, Jackson County, Blue Ridge Parkway, Waterrock Knob , ridge samples 3‒5, 648103N 763749E, spruce-fir forest , 29 April 2002, J. Robertson, coll.; four paratypes in alcohol, same locality data except ridge samples 8 & 9, 648102N 763704E; two paratypes in alcohol and two females mounted on slides , same locality except streamside creek samples 8 & 9, 646557N 766443E, 29 April 2002 .

Description. White; length 757‒899 µm; antennae shorter than head, ratio of Ant. I‒IV as 1:1.2:1.6:2.2; strongly heterochaetotic, dorsal head setae differentiated as microsetae, mesosetae and macrosetae ( Fig. 13 A). Pseudocellar formula 11/122/22221; pseudocelli primarily Type III (crescentic) ( Fig. 13 F), sometimes apparently structureless; small lateral pseudocelli with uniform surface, without internal structure. Pseudocelli bordered by individual granules occasionally coalescing into larger masses. Pseudopores absent. Anal spines about 1.7× length of hind unguis.

Granules on dorsum of head of variable size (diameter 1.3‒2.7 µm, mean 2.0 µm), evenly distributed, round. Thoracic nota and Abd. I‒II with strong mid-dorsal band of about 16 longitudinal rows of large granules (diameter 1.6‒2.0 µm, mean 1.8 µm), subdorsal fields with smaller granules (diameter 1.1‒1.4 µm, mean 1.3 µm) ( Fig. 14 D). Abd. III‒V granulation densely packed, not in longitudinal rows ( Fig. 14 E). Posterior region of all segments except pronotum and Abd. VI with about 15 distinct transverse rows of granules between the dorsal pseudocelli ( Figs 14 D, E). On Abd. VI granules smaller on anterior than on posterior, diameter of larger posterior granules 1.8‒3.1 µm (mean = 2.3 µm).

Labial palpus lacking papilla E; spines of papillae A‒D pointed, not rounded at tip, spine of C shorter than the others; seven guard setae, of which a1, b1 and d1 reduced to minute knobs; two slender guard setae associated with papilla B, two associated with papilla D ( Fig. 13 E). Hypostomal seta H and guard setae h1 and h2 normal. Basomedian area of labium with five setae. Outer lobe of maxilla without sublobal setae but terminal seta long and robust. Two prelabral setae; labral setal formula 3-4-2, distal pair of setae stout, proximal setae and outer setae of middle row minute ( Fig. 14 C). Mandible with four teeth ( Fig. 13 D). Postantennal organ with two rows of oval vesicles with about 25 vesicles per row; several small vesicles forming a short middle row in the outer half of the PAO ( Figs 13 F, 14A, B).

Antennal segment IV with seven prominent curved sensilla and several thinner, straight sensilliform setae with finely rounded tips; four pointed setae mid-dorsally; microsensillum a short rod set in shallow groove; organite peg-like; apical bulb stalked, spherical, granulate ( Fig. 13 G). Ventral face of Ant. IV with eight sensilliform setae, four of them sub-distal, straight, one twice the length of the others; weak ventral field region with about 16 short, pointed setae ( Fig. 13 H). Ant. III dorsal sense organ with three large sense clubs and two sense rods partially or wholly covered by integumentary folds, and four guard setae; sense rods minutely lobed along apex. Ant. III ventral sense club present; all Ant. III setae pointed ( Fig. 13 H).

All leg setae pointed. Trochanter with 4 setae, femur with 8 setae. All tibiotarsi with 11 setae ( Fig. 13 I). Unguis stout, without teeth; unguiculus pointed. Tenacular region on Abd. III venter indicated by ungranulated transverse oval between a1 and m1 setae; furcal region on Abd. IV indicated by ungranulated T-shaped region between a1 and p1 setae ( Fig. 13 J).

Head heterochaetotic, seta a0 a mesoseta; one medial microseta anterior to a0; d1 and d4 microsetae; seta d2 longer than other d-setae, sd3 and sd5 longer than sd1 and sd4; g3, g5, oc2 and p5 macrosetae and c5 longer than other c-setae; c5 posterior to c4. Seta v1 present, v2 absent. Six setae between posterior cephalic pseudocelli, p1 and p2 about equal in length ( Fig. 13 A). Pronotum with 8 setae. Mesonotum and metanotum each with m-row consisting of m1, m3, m4 and m5; setae a3, m4 and p5 the longest in their respective rows; seta p1 absent on mesonotum, present on metanotum, where p2 is longer than p1; microsensillum in shallow pit near m5. Abd. I with seta m4, Abd. II‒IV with five a-setae and with m4 and m5; p2 more than twice the length of p1 on Abd. II and III, p2 slightly longer than p1 on Abd. IV and displaced anteriorly ( Fig. 13 B). On Abd. V seta p1 absent, p2 short, not displaced anteriorly; p3 tapering ( Fig. 14 E, upper inset); a2, a5 and p5 macrosetae. Abd. VI seta a2 thickened, minutely rugose on convex side ( Fig. 14 E, lower inset).

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 setae occasionally exhibiting some asymmetry. Abd.

III sternum with seta p0. Abd. IV sternum with m-row consisting of m1, m3, m5; seta p1 well anterior to p2, seta p4 present ( Fig. 13 C). Genital aperture on Abd. V with five surrounding setae and two microsetae on anterior lip. Ventral lobes of Abd. VI with full complement of setae ( Fig. 14 F). Pleural regions of Abd. II‒IV each with anterior and posterior blunt sensilliform setae.

Etymology. This species is named nearctica to denote its North American habitat and to recognize its similarity to the Holarctic species T. arctica Wahlgren, 1900 .

Remarks. On Abd. IV setae m4 and m5 are shifted medially and appear to be in the m3-m4 positions. However, their pattern of short and long setae corresponds to that on other abdominal segments and therefore are labeled m4 and m5.

Four of the 22 Tullbergia spp. with three sense clubs on Ant. III have the same pseudocellar formula as T. nearctica n. sp.: T. alcirae Palacios-Vargas & Salazar Martinez, 2014 ; T. antarctica Lubbock, 1876 ; T. arctica ; and T. maxima Deharveng, 1981 ( Deharveng 1981, Fjellberg 1984, 1998). Tullbergia alcirae has four setae between the Th. III posterior pseudocelli, has seta p2 anterior to p1 on Abd. IV, lacks setae p1 and p2 on Abd. V, and possesses two clavate ventral setae on each tibiotarsus ( T. nearctica n. sp. with six setae between the Th. III pseudocelli, Abd. IV seta p2 posterior to p1, seta p2 present on Abd. V, all tibiotarsal setae pointed). The other three species ( T. antarctica , T. arctica , T. maxima ) have 2+2 cephalic v-setae, whereas T. nearctica n. sp. has only 1+1 v-setae. Of the three, T. nearctica n. sp. is most similar to T. arctica in chaetotaxy. The new species possesses seta m3 and lacks p4 on the mesonotum and metanotum ( T. arctica without m3, with p4, see Fjellberg 1984, 1998). On Abd. IV T. nearctica n. sp. possesses seta a3, which is absent in T. arctica .

Figures

FIGURE 13. Tullbergia nearctica n. sp. A) Head, dorsal view. B) Thorax and abdomen, dorsal view. C) Abdominal segments II ‒ VI, ventral view. D) Mandible apex. E. Labial palp. F. Postantennal organ and anterior pseudocellus. G) Third and fourth antennal segments, dorsal view. H) Third and fourth antennal segments, ventral view. I) Hind leg. J. Smooth region on venter of Abd. IV. Scales: A, 50 µm; B, C, 100 µm; D ‒ F, 10 µm; G ‒ I, 20 µm; J, 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.