Scutisotoma champi Soto-Adames & Giordano

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 : 27-28

Scutisotoma champi Soto-Adames & Giordano sp. n.

Material.

Holotype– Female, slide mounted, locality B. Paratypes– Locality B, 9 individuals on slides, 1976 in alcohol; N, 5 mounted on two slides and more than 3000 in alcohol; P, 4 individuals on slides and 59 in alcohol; Other material– Locality A, 800 individuals in alcohol; C, 7 in alcohol; D, 187 in alcohol; E, 30 in alcohol; F, 32 in alcohol; G 1186 in alcohol; H, 1290 in alcohol; J, 158 in alcohol; K, 35 in alcohol; L, 1723 in alcohol; M, 1555 in alcohol; Q, 5 in alcohol; R, 2 in alcohol; S, 1 in alcohol; T, 8 in alcohol.

Type Locality.

USA, Vermont, Chittenden Co., Burlington, Pine Street Canal, near water treatment plant at south end of Battery St., N 44.46859 W 73.21901

Etymology.

The species is named after ‘Champ’ the denizen monster of Lake Champlain, were the new species seems to be most abundant.

Description.

Length to 0.7 mm. Live specimens black, alcohol preserved individuals (Fig. 29) dark purple, with pigment more or less uniformly distributed throughout head, body and antennae; legs and manubrium light purplish brown. Ant. 4 with 1 basal microsensilla, and 7 poorly differentiated thin-walled sensilla distributed along apical half of segment; subapical sense organ with 1 poorly differentiated microsensilla and 1 micropeg in a pit. Ant. 3 with 1 basal microsensilla; sense organ with 2 clubbed sensilla and 2 differentiated guard sensilla; 1 lateral sensilla present; males with 2 additional dorsal sensilla. Ant. 2 with 3 basal microsensilla and 1 distal sensilla. Ant. 1 with 2 basal microsensilla and 1 whorl comprising 11 setae and 2 sensilla. Eyes 8+8, G and H slightly smaller than others (Fig. 30), with 3 interocellar setae; PAO elliptical, about 2.3X diameter of eye B, with 4-5 associated setae. Prelabral and labral chaetotaxy 4/554; distal labral margin smooth. Papilla of outer maxillary lobe bifurcate, sublobal plate with 4 appendages (Fig. 31). Maxilla with lamella 1 narrow, surpassing the tip of capitulum, with cilia confined to external margins (Fig. 32). Labial palps with a full complement of papillae and 3 proximal setae; papillae E with blunt lateral process and 7 guards, e7 detached from papilla (Fig. 34); labial triangle with 5 anterior and 4 posterior setae; distribution of postlabial setae in columns I, C, E and L as 4,3,2,3 (Fig. 35). Body dorsally covered by smooth hairs; some hairs on the pre-posterior row reaching base of setae on posterior row; thorax without ventral setae; axial setae on Th. 2-Abd. 3 as 6-8, 6-7//4-5, 4-5, 4-5; Th. 3 with 20-22 setae on posterior row; microsensillar and sensillar formulae 11//111 and 33//22224, respectively (Figs. 33, 36); lateral sensilla on Abd. 5 swollen (Fig. 36), all sensilla inserted anterior to posterior row of setae, tergal macrochaetae smooth, poorly differentiated, distributed as 11//11124; Abd. 5≈ 3.2X medial macrochaeta. Proximal and medial subcoxae on legs 1-3 with 1, 1; 3(4), 6(7); 5(4,6,7), 7(6,8) setae (Fig. 38). Lateral valve of Abd. 6 similar to Ballistura joycei , with 3 hr setae. Tibiotarsal whorl B complete; male metatibiotarsal setae x and B5 thin, short, bothriotrica-like, with modified sockets (Fig. 37); legs 1-3 with 1,2,2 tenent hairs as in Ballistura joycei , but all tenent hairs acuminate, A1 on L2 sometimes appearing weakly clubbed. Unguis and unguiculus toothless (Fig. 37). Ventral tube with 3+3 apical setae, posterior face with 1 basal and 4 distal setae. Tenaculum with 4+4 teeth and 1 seta. Anterior and posterior furcal subcoxae with 12-18 and 7-8 setae, respectively. Proportion manubrium/dens/mucro as 6/4/1. Chaetotaxy of furcula as in Figure 39: manubrium with 17-18 dorsal and 1 ventral setae; dens weakly crenulated, with 9 dorsal and 6 ventral setae. Mucro bidentate, subapical tooth longer than apical (Fig. 40).

Remarks.

Scutisotoma champi sp. n. is unique among Scutisotoma species in having a lamelate bidentate mucro, 4 tenacular teeth, 9 dorsal and 6 ventral setae on dens, and maxillar lamela 1 longer then the capitulum. The new species is most similar to the Central Asian Scutisotoma acorrelata Potapov, Babenko & Fjellberg, 2006 and Scutisotoma tenuidentifera Potapov, Babenko & Fjellberg, 2006, from which it can be distinguished by the characters listed in Table 4. Among North American species, Scutisotoma champi sp. n. is most similar to Scutisotoma titusi (Folsom), 1937 from which it can be easily distinguished by the number of ventral setae on dens and the number of tergal sensilla on Abd. 4 and 5 (2+2, 4+4 in champi, 7-8+7-8, 8-12+8-12 in titusi).

Scutisotoma champi sp. n. is the most common species found in sandy beaches on the northern 2/3 of Lake Champlain as well as Lake Willoughby and Greater Averill Pond, and it is likely present in most if not all lakes and large ponds in northern Vermont and southern Quebec. The species was collected in apparently healthy beaches (e.g., Pearl Bay, locality H), as well as on highly disturbed, strongly compacted beaches (e.g., Colchester Beach, locality C). The species is most abundant in beaches with aquatic plant litter, but it is also found in sand in beaches without visible surface plant remains.