Brachystomella garayae, Queiroz, Gabriel C. & Weiner, Wanda M., 2011

Queiroz, Gabriel C. & Weiner, Wanda M., 2011, A new species of Brachystomella (Collembola: Brachystomellidae) from the Atlantic Forest of southeast Brazil, Zootaxa 2885, pp. 65-68 : 65-68

Brachystomella garayae sp. nov.

Figs 1–10, Tabs 1 –2

Type material. Holotype female (Nº 1968 CM/ MNRJ) 20.xi.2008 and 5 paratypes: 1 female and 1 juvenile (Nº 1829 CM/ MNRJ) 10.iv.2007; 1 female and 1 male same data of holotype; deposited in MNRJ; 1 male, same data of holotype deposited in ISEA.

Type locality. Sooretama, Espírito Santo, Brazil. Forest leaf litter of Table Land Atlantic Forest, about 100 m above sea level, 40 km from the coast line. Gabriel Queiroz leg.

Description. Holotype length (female): 0.98mm. Length (range): 0.65–1.10mm. Colour in ethanol: pale aspect, yellowish with diffuse blue pigmentation; well developed cuticular granulation. Eyes light blue.

Head without chaeta a0, with 2+2 Oc chaetae on ocular plate (1+ 1 in two specimens), 5+5 chaetae on d row, 3+3 chaetae on sd row, p row with 3+3 chaetae. PAO with 5–6 vesicles, almost twice as long as ocellus B. Eyes 2+2 (Fig. 1). Ratio length head: antenna = 1.4. Ant. I with 7 chaetae. Ant. II with 12 chaetae. Ant. III and IV fused dorsally. Sensory organ of third antennal segment with two small internal globular sensilla with well developed granular tegument, two longer and subcylindrical guard sensilla, the dorsal shorter than ventral sensillum, ventral microsensillum present (Fig. 2). Ant. IV with ordinary chaetae and five subcylindrical sensilla, dorsoexternal microsensillum, subapical organite present with a concave apex (Fig. 2). Apical vesicle trilobed (Fig. 2 and 3).

Mandible absent, maxillae with 8–9 teeth (Fig. 4). Labral chaetotaxy 2/2334. Buccal cone and labium typical of the genus (Fig. 5).

Tibiotarsi I, II and III with 19, 19, 18 chaetae, respectively, without tenent hairs (Fig. 6). Distal whorl of tibiotarsi I, II and III with 11 chaetae each, M chaetae present. Femora I, II and III with 12, 11 and 10 chaetae, trochanter I, II and III with 5, 5 and 4, respectively. Coxae I, II and III with 3, 5 and 7, subcoxae 2. of legs I, II and III with 0, 2 and 2, subcoxae 1 of legs I, II and III with 1, 2 and 3, respectively. Claw with a minute basal inner tooth on leg I–III.

Ventral tube with 3+3 chaetae. Tenaculum with 3+3 teeth. Furca well developed with 5 chaetae on each dens. Mucro straight and separated from dens (Fig. 7).

Dorsal chaetotaxy of body as in Fig. 8: short ordinary chaetae and longer sensory chaetae, ratio of lengths 1:5. Apex of s-chaetae slightly capitate. Half tergum formula of sensilla: 022/21111. Microsensilla present on Th. II. Th. I with 2+2 chaetae. Abd. I–IV with s-chaetae as p 3 and Abd. V as p2. Abdominal sterna II–III with 3+3 chaetae each.

Each paired anal valve with 12–13 chaetae and 2 hr microchaetae. Unpaired valve with 2 mesochaetae (Fig. 9). Males without secondary sexual characters; genital plate of male as in Fig. 10.

Etymology. The species is named after and dedicated to Dr. Irene Garay (UFRJ, Brazil), for the many years of support and friendship to her students.

Discussion. This is the first species of the genus Brachystomella with fewer than 5+5 eyes. The difference in the number of ocelli (2+2) is sufficient to distinguish the new species from the group of species listed below, but other distinguishing characters are the 2+2 Oc chaetae (Oc3, Oc1) or 1+1 (Oc3 only present in two specimens) in the new species and 3+ 3 in the other species. In addition, the two small globular sensilla of the sensory organ of the third antennal segment have a well developed granular tegument. The combination of following characters: 2+2 chaetae on Th. I, five chaetae on each dens, 19, 19, 18 chaetae on tibiotarsi and the absence of chaeta a0 on the head places the new species in a group with B. contorta , B. desutterae , B. septemoculata and B. zerpa described from the Neotropical region ( Table 1 ). They also share the same number of hr-chaetae on anal valves (2+2), except B. desutterae which possesses only 1+1 chaetae.

on head.

Najt et al. (2005), in a phylogenetic study of Brachystomellidae , considered that, of the 16 extant genera of the family, only the genus Brachystomella seems to be polyphyletic, because some of the species of Brachystomella studied clustered either with Rapoportella Ellis & Bellinger or with the species Micronella porcus (Denis) + Folsomiella caeca (Folsom) + Maricaella duna Mendonça & Fernandes + Winterella arlesiana Massoud. The clade composed of the species Folsomiella caeca, Maricaella duna and Winterella arlesiana was supported by two synapomorphies, they are 2 + 2 chaetae Oc on the head and coxa III with six chaetae ( Najt et al. 2005).

Brachystomella garayae sp. nov. is the first species in the genus to have 2+2 Oc chaetae as well as 2+2 ocelli and to be almost lacking body pigment. Table 2 lists that the shared characters indicate the similarity of the new species with the genera Folsomiella Bonet, 1930, Maricaella Mendonça & Fernandes, 1997, Micronella Arlé, 1959 and Winterella Massoud, 1967 .

FIGURES 1–10. Brachystomella garayae sp. nov.: 1, Chaetotaxy of head with detail of PAO and eyes; 2, Ant III–IV, dorsal view; 3, Ant III–IV, ventral view; 4, Maxilla; 5, Labium; 6, Tibiotarsus I; 7, Furca: dens; 8, Dorsal chaetotaxy of body; 9, Anal valves; 10, Male genital plate.

We wish to express our gratitude to Dr. Maria Cleide de Mendonça and Dr. Liliane Henriques Fernandes for thoughtful comments on previous drafts; the Sooretama Biological Reserve (ICMBio) and CAPES, FAPERJ and CNPq for financial support. The comments by Penelope Greenslade and an anonymous reviewer helped us to improve the clarity of the present contribution.

Tables

TABLE 1. Neotropical species of the genus Brachystomella Ågren, 1903 with 2 + 2 chaetae on thorax I and without chaeta a 0

Species Eyes PAO vesicles	Maxilary teeth	Apical bulb	Ant.IV sensilla	S chae- tae	Mucro shape	Chaetae hr	Known distribution
B. contorta Denis , 8+8 5–6 1931	7	simple	5	simple	lamelated	2+2	Costa Rica; Argentina
B. desutterae Weiner 8+8 7 & Najt, 2001	7	trilobed	6	simple	simple	1+1	Peru
B. septemoculata 7+7 5 Denis, 1931	8	simple	5	simple	slightly curved	2+2	Costa Rica; Méx- ico
B. zerpa Weiner & 5+5 5 Najt, 2001	8	trilobed	6	simple	slightly curved	2+2	Venezuela
B. garayae sp. nov. 2+2 5–6	8–9	trilobed	5	slightly clavate	simple	2+2	Brazil (ES)
Affinities among genera and remarks