Pogonognathellus brevifulvus, Park, Kyung-Hwa, Bernard, Ernest C. & Moulton, John K., 2011

Park, Kyung-Hwa, Bernard, Ernest C. & Moulton, John K., 2011, Three new species of Pogonognathellus (Collembola: Tomoceridae) from North America, Zootaxa 3070, pp. 1-14 : 6-9

Pogonognathellus brevifulvus n. sp.

( Figs. 3 , 4 , 7 B, H, I))

Maximum length up to 5 mm. Scale covering yellowish brown to grey-brown, posterior edges of segments appearing banded with transverse rows of large brown and grey scales ( Figs. 3 A, B); bothriotricha surrounded by a few white scales, those on Abd. IV with only 1 or 2 white scales; scales of Abd. IV weakly iridescent (Fig, 3C). Cuticle yellow-orange to orange ( Figs. 3 D–G). Eye patches dark blue to black, roughly triangular. Small pigmented spot directly posterior to eyespot. Antennal base purple, prominent ring-shaped. Small pigmented triangular patch between bases of antennae. Antennal segments with dark brown pigment, interantennal segments pale. Legs with dark orange to dark brown pigment, gradually becoming dark brown distally; coxae of all legs orange. Ventral tube and manubrium orange; dens and mucro pale.

Eyes 6+6. Antennae shorter than body, up to 0.9 times body length. Fourth segment fusiform, with rounded apex, with 9–11 subsegments; rod-like sensilla scattered sparsely along its length; pin seta slender, finely rounded at tip, with proximal spur ( Fig. 7 H); stout spike-like seta near base of pin seta; one truncate sensillum near apex with associated hooked setae and rod-like sensillum slightly behind hooked setae ( Fig. 7 H). More proximally, longer setae composed of thin sensilliform setae with rounded tips and pointed sensilliform setae in weakly defined sockets. Apex of Ant. III with truncate sensillum and associated hooked seta, 1 pair of rod-like sensilla, and several scattered rod-like sensilla; longer setae consisting of typical setae and slender, round-tipped sensilliform setae ( Fig. 7 I).

Maxilla with broad lamella 1 bearing many rows of strong curved rake-like denticles behind the apical border of fine cilia. Lamella 2 with two regular rows of curved coarse rakes followed by a proximal field of finer denticles. Lamella 5 without prominent proximal beard-like projection but with long basal teeth ( Fig. 4 F).

Ungual inner teeth usually 4, rarely a specimen with 3 teeth on one unguis, evenly spaced on inner margin; number of teeth sometimes different on unguis of the same pair of legs. Third inner tooth from base of fore and middle unguis usually above the tip of the unguiculus. Wavy internal ridging of unguis prominent. Unguiculus lanceolate, usually with one small inner tooth, sometimes tooth absent. Tenent hair clavate, moderately stout, as long as the inner margin of unguis ( Figs. 4 B–D). Two strong spines on metatibiotarsus, one proximal and longer, the other distal and shorter ( Fig. 7 B); fore and mesotibiotarsi without differentiated spine-like setae. Pretarsal setae finely ciliate.

Manubrium dorsally with acuminate macrochaetae. Dens with spine-like scale at inner base. Dental spines brown, smooth to finely striate, terminal spines considerably longer than others, furcula 0–2, 2 /5–6, 2, usually 2 /5– 6, 2 ( Fig. 4 G), number of spines sometimes different on each side. Mucro elongate with numerous ciliate setae, basal lamella, and 8–13 intermediate teeth; basal tooth less than one-fourth length of mucro away from base, lateral mucronal tooth even with basal lamella, slightly proximal to basal tooth; apical teeth subequal ( Figs. 4 H, I).

Head with 2+4 antero-medial macrochaetae, 2+2 interocular macrochaetae, 2+2 postocular macrochaetae, and 2+2 posterior cephalic macrochaetae ( Fig. 4 A). Tergal macrochaetae on each side 10,3/3,3,6,3,3; Abd. III with 2+2 anterior and 4+4 posterior macrochaetae. On Abd. IV one pair of anterior and two pairs of posterior macrochaetae ( Fig. 4 E). Caudal setae of Abd. VI short and straight, length about equal to segment; setae of Abd. V longer, curved, length about equal to Abd. V+VI, directed caudally. Tenaculum corpus with 1 seta.

Etymology. The name of this species is formed from two Latin words, brevis (small) and fulvus (reddish yellow), and refers to the relative size of this species compared to the largest members of the genus, in addition to its distinctive, orange pigmentation.

Type specimens. Holotype female and 5 paratypes, Massachusetts, Worcester County, Hwy 62 west of Sterling, 42.44775N 71.85141W, elev. 204 m, mixed maple-hemlock-pine forest, on sticks on ground, 8 October 2008, E. C. Bernard, coll.

Type deposition. Holotype and 2 paratypes deposited in INHS, 3 paratypes in UTIC.

Additional material. Four specimens, Michigan, St. Clair County, Algonac State Park, 42.65317N 82.51841W, elev. 172 m, 25 July 2008, oak forest next to archery range, leaf litter, 25 July 2008, E. C. Bernard, coll.

Diagnosis. Pogonognathellus brevifulvus n. sp. is distinguished from other species of the genus by its orange cuticular colour, presence of 4 small, evenly spaced ungual teeth, absence of spines on the fore and mid-tibiotarsi, and basal position of the lateral mucronal tooth. It resembles P. m y s t a x in the shape of the unguis and the distribution of the dental teeth, but the species differ in head chaetotaxy ( P. brevifulvus n. sp. possesses posterior cephalic macrochaetae, P. m y s t a x lacks them), and in clypeal colour (that of P. brevifulvus n. sp. is orange to orange-brown, that of P. m y s ta x is violet and resembles a moustache). The orange cuticular colour also occasionally occurs in strongly pigmented specimens of the following species ( P. magnibrunneus n. sp.), but the lack of spines on the fore and middle tibiotarsi immediately distinguishes P. brevifulvus n. sp. This species has not been characterized molecularly.

Figures

FIGURE 3. Pogonognathellus brevifulvus n. sp. (A – C) Live specimens. (A) Dorsal view, specimen from Worcester County, Massachusetts, anterior and posterior illumination. (B) Dorsal view, specimen from St. Clair County, Michigan, anterior and posterior illumination. (C) Posterior abdomen of second specimen from Worcester County, MA, high-angle anterior illumination. (D – G) Lateral views of specimens in ethanol. (D) Specimen from Sevier County, TN. (E – F) Specimens from Worcester County, MA. (G) Enlargement of specimen in Fig. 2 F. Scale bars: A, B, D – F, 2 mm; C, G, 1 mm.

FIGURE 4. Pogonognathellus brevifulvus n. sp. (A) Dorsal head chaetotaxy. (B – D) Fore, middle and hind foot complex, respectively. (E) Dorsal body chaetotaxy, left side: filled circles indicate macrochaetae, wavy lines indicate bothriotricha. (F) Maxilla. (G) Dental spines, right side. (H) Mucro, dorso-lateral view. (I) Mucro, lateral view. Scale bars: A, 200 μm; B-D, F, H, I, 50 μm; E, 400 μm; G, 100 μm.

FIGURE 7. Pogonognathellus spp. characters. (A – C) Tibiotarsal spine distribution. (A) Foretibiotarsus of P. belmontorum n. sp., no spines. (B) Hind tibiotarsus of P. brevifulvus n. sp., two ventral spines (arrows). (C) Hind tibiotarsus of P. magnibrunneus n. sp., seven ventral spines (arrows). (D – N) Antennal characters. (D) P. magnibrunneus n. sp., distribution of setae on annules of third antennal segment, optical cross-section near setal bases. (E – G) P. belmontorum n. sp. (E) Fourth antennal segment, sensilla and apical setae shown. (F) Apex of fourth antennal segment, arrow points to enlargement of truncate sensillum. (G) Apex of third antennal segment. (H, I) P. brevifulvus n. sp. (H) Apex of fourth antennal segment, most setae illustrated. (I) Apex of third antennal segment. (J – N) P. magnibrunneus n. sp. (J) Fourth antennal segment, only sensilla shown. (K) Apex of fourth antennal segment, one truncate sensillum. (L) Apex of fourth antennal segment, 3 truncate sensilla (small arrows). (M) Apex of third antennal segment. (N) Apex of regenerating antenna. Abbreviations: PLS, plump sensillum; PSS or circle, pointed sensilliform seta; RSS or circle with central dot, slender sensilliform seta with rounded apex; SE or darkened circle, typical dark, pointed seta; RLS, rod-like sensillum; SP, spike-like seta; SH, hooked seta; TRS, truncate sensillum. Dotted sensilla are on other side of segment. Scale bars, A – C, 100 μm; D, 20 μm; E, J, 100 μm; F – I, K – N, 50 μm.