Pachyotoma Bagnall, 1949

Soto-Adames, Felipe N. & Giordano, Rosanna, 2011, New species of springtails in the Proisotoma genus complex from Vermont and New York, USA with descriptive notes on Ballistura alpa Christiansen & Bellinger 1980 (Hexapoda, Collembola, Isotomidae)., ZooKeys 147, pp. 19-37 : 28-29

Genus Pachyotoma Bagnall, 1949

Pachyotoma alpa (Christiansen & Bellinger), 1980 new combination

Ballistura alpa Christiansen & Bellinger, 1980: 581 (Mt. Washington, New Hampshire, USA)

Material Examined.

USA, Vermont, Chittenden Co., Bolton, Camel’s Hump ≈1200-1230 m elevation, 7 August 1972, W. Rittenhouse, coll. Two slides, one with three individuals, the other with one individual. These are the individuals originally determined as Ballistura alpa by Bellinger (1982).

The following notes serve as a complement to the original description. Cuticle covered by many secondary granules. Organite of Ant. 4 capitate, guard sensilla not strongly modified (Fig. 42). Ant. 3 sense organ, lateral and supplementary sensilla as in Fig. 43. Ant. 2 with 1 distal sensilla and at least 1 basal microsensilla. Ant. 1 with 2 weakly modified basal microsensilla, 3-4 sensilla, and 12-14 setae. Eye patch with 3 setae, PAO with 2 guard setae. Labral formula 4/5,5,4. Apical seta of outer maxillary lobe bifurcate, sublobal plate with 4 appendages. Maxillary lamellae not clearly seen, but lamella 1 apparently surpassing tip of capitulum and apically acuminate (lateral margins converging well before tip of lamella), with cilia only along lateral margins. Labial papilla E with 7 guard setae, e7 detached from papilla as in Scutisotoma champi . Labial triangle with 5 anterior and 4 posterior setae. Postlabium with 3(4), 2, 1, 3 setae in columns I, C, E and L, respectively (Fig. 44). Body setae smooth and short, tip of seta on anterior rows not reaching base of setae on posterior rows. T horacic sterna without hairs. Axial setae on Th. 2-Abd. 3 as 3-4, 5//4, 2-3, 2-4; Th. 3 with 18-20 setae on posterior row; microsensillar and sensillar formulae as 11//111 and 8(10)8//7758(9)7, respectively (Fig. 41); Th. 2 with 2 lateral sensilla inserted anterior to medial sensilla; medial sensilla on all segments inserted on p-row; Abd. 5 sensilla not swollen. Tergal macrochaetae undifferentiated. Proximal and medial subcoxae on legs 1-3 with 1, 0; 4(5), 4; 5(7), 4 setae. Lateral valves of Abd. 6 similar to Ballistura rossi , with 1 hr seta (Fig. 46). Tibiotarsal whorl B complete; legs 1-3 with 1, 2, 2 tenent hairs, all acuminate. All unguis with 1 inner tooth; unguiculus toothless, without terminal filament. Ventral tube with 7+7 apical setae, posterior face with 2 basal and 4 distal setae. Tenaculum with 4+4 teeth and 1 seta. Anterolateral, anteromedial and posterior furcal subcoxae with 7/8(6,10), 11 (12,13) and 7-11 setae, respectively (Fig. 47). Manubrium with 15 dorsal and 0 ventral setae. Dens granulate, with 7-8 dorsal and 6 (5) ventral setae. Mucro bidentate, subapical tooth longer than apical (Fig. 45).

Remarks.

This species was originally placed in the genus Ballistura , but the presence of a complete whorl B on pro- and mesothoracic legs and four prelabral setae excludes it from that genus ( Potapov 2001). The presence of secondary granules on the cuticle in combination with a well developed furcula and the insertion of the medial and almost all other tergal sensilla on Th. 2-Abd. 3 on the posterior row of setae place this species in the genus Pachyotoma . In the original description of the species Christiansen and Bellinger (1980) indicate the presence of 5 distal setae on the ventral tube and a toothless unguis. The individuals from Vermont have 7 distal setae on the ventral tube and one distinct inner tooth on all unguis and may represent a distinct species.