Entomobrya juneae, Santos & Santos-Costa & Siqueira & Godeiro & Bellini, 2020

Santos, Nathália Michelly Da Cunha, Santos-Costa, Renata Clicia Dos, Siqueira, Orquianne Judy Rafael, Godeiro, Nerivânia Nunes & Bellini, Bruno Cavalcante, 2020, Two new species of Entomobrya Rondani (Collembola, Entomobryidae) from northeastern Brazil and comments on the genus, Zootaxa 4731 (1), pp. 43-62 : 45-52

Entomobrya juneae sp. nov. Santos, Santos-Costa & Bellini

Figs 1 – 24 , Table 1

Type material. Holotype female in slide ( CC /UFRN): Brazil, Rio Grande do Norte State, Extremoz municipality, Área de Proteção Ambiental de Genipabu ( APA) (05º41’56.89”S; 35º12’27.17”W), 21.viii.2012, M. J. C. Meira coll. Paratypes in slides ( CC /UFRN): 8 females and 11 males, same data as holotype .

Diagnosis. Trunk colour pattern with pigmented lateral edges on Th. II – Abd. IV, central Abd. II, posterior Abd. III–IV, Abd. V almost entirely pigmented; antennae shorter or as long as the trunk ( Fig. 1 ). Dorsal chaetotaxy of head with M1, M3, S0–1 mac ( Fig. 6 ). Prelabral chaetae smooth ( Fig. 7 ). Labial chaetae M, L1–2 ciliate, others smooth, R absent ( Fig. 9 ). Th. II with 2 main m mac (m1 and m4), m5 and p5 absent ( Fig. 11 ). Abd. I with 5 – 8, Abd. II with 5 and Abd. III with 1–2 central mac respectively, Abd IV with 7 – 9 central and 11–13 lateral mac ( Figs 13 – 16 ). Unguiculi slightly truncated with smooth edges ( Fig. 18 ). Trochanteral organ with about 25 smooth spine-like chaetae ( Fig. 19 ). Ventral tube anteriorly with 2+2 distal mac ( Fig. 20 ). Mucro distal tooth reduced when compared to proximal one; mucronal spine reaching the apex of proximal tooth ( Fig. 24 ).

Description. Habitus typical of Entomobrya ( Fig. 1 ), average body length (head + trunk) 1.3 mm, holotype length 1.63 mm. Specimens fixed in ethanol with yellowish to pink background with dark blue pigment on distal Ant. I–II, Ant. III–IV (or all antennae pigmented), lateral edges of Th. II – Abd. IV, central Abd. II, posterior Abd. III–IV, Abd. V almost entirely pigmented; legs and manubrium weakly pigmented; eyes black ( Fig. 1 ).

Head ( Figs 2 – 10 ). Antennae as long as trunk or smaller, ratio antennae: body of holotype 1:2.11; ratio antennal segments of holotype Ant. I: II: III: IV equal 1:2:2.1:2.75. Ant. IV lacking subdivisions or clear annulations, with a simple and apically rounded apical bulb ( Fig. 2 ), rarely apically constricted ( Fig. 3 ), with ciliate chaetae and smooth sens of different sizes (partially represented in Figs 2–3 ) plus a dorsal modified short sens; ventrally with a subapical modified large sens ( Fig. 2 ). Ant. III sense organ typical with 2 sensory rods and 3 small guard sensilla ( Fig. 4 ). Eyes 8+8, largest lenses ‘A’ to ‘F’, smallest ‘G’ and ‘H’, with 3 interocular mes (p, s and t) ( Figs 5–6 ). Head dorsal chaetotaxy as in Fig. 6 , with antennal (An) series with 4 (An1a–3); anterior (A) series with 4 (A0, A2–3 and A5); medial (M) series with 4 (M1–4); sutural (S) series with 7–9 (S’0, S0–5, S’0 present or absent, S4i as mac or mic); post-sutural (Ps) series with 1 (Ps2); post-occipital anterior (Pa) series with 4 –5 (Pa1 present or absent plus Pa2–3, Pa5); a single mac without clear homology near Pa2; post-occipital medial (Pm) series with 2 (Pm1 and Pm3); and post-occipital posterior (Pp) series with 4 (Pp1, Pp3–5) mac; Pp1e, Pe3 and at least 3 more postero-external mac present. Labrum as in Fig. 7 with 4 prelabral smooth chaetae (pl1–2) and with 5 (p0–2), 5 (m0–2), 4 (a1–2) smooth chaetae, p0–1 longer than other labral chaetae; labral papillae with multiple projections (about 6 projections each). Maxillary palp with 1 apical appendage and 1 subapical chaeta, subequal and smooth; sublobal plate with 3 chaetaelike internal appendages ( Fig. 8 ). Labium as in Fig. 9 with 5 main papillae (A–E) with 0, 5, 0, 4, 4 guard chaetae respectively; lateral process (l.p.) thin and apically rounded surpassing papilla E apex; papilla H with 2 guard chaetae; labial palp with 5 smooth proximal chaetae. Labial basomedian and basolateral fields with a1–5 and e as smooth chaetae, M (rarely absent or as smooth chaeta) and L1–2 as ciliate chaetae; R absent ( Fig. 9 ). Post-labial region only with ciliate chaetae, ventral groove with 4 – 6 marginal chaetae, posterior chaeta longer than anterior ones ( Fig. 10 ).

Trunk dorsal chaetotaxy ( Figs 11 – 17 ). Th. II to Abd V dorsal sens and ms formulae as 22/122+3 and 10/10100 respectively. Th. II ( Fig. 11 ), excluding anterior collar, with 1 anterior (a5), 2 medial (m1 and m4) and 10 – 14 posterior (p1–4, p6–6e; p1i, p1p2, p2p and p4a present or absent) mac; m5 and p5 mac absent. Th. III ( Fig. 12 ) with 10 anterior (a1–6), 2 medial (m6–7?) and 7–14 posterior (p1–3, p5–6p; p1i, p1i2, p1a, p1a2, p2a, p2ep and p3 present or absent) mac. Abd. I ( Fig. 13 ) with 2 – 4 anterior (a1–3, a5, a2 as mic or mac, a3 present or absent), 5–6 medial (m2–6e, m5 present or absent) plus one extra lateral mac (?). Abd. II ( Fig. 14 ) with 2 bothriotricha (m2 and a5), 5 central (a2, m3–3ea) and 1 lateral (m5) mac. Abd. III ( Fig. 15 ) with 3 bothriotricha (m2, a5 and m5), 1 – 2 central (a1 and m3, a1 present or absent) and 3 lateral (am6, pm6 and p6) mac. Abd. IV ( Fig. 16 ) with 2 bothriotricha (T2, T4), 7 – 9 central (A6, Ae6–7, B2, B4–6, C4 and T7; the last two as mes or mac) and 11–13 lateral (D2–3, E3–4, Ee3, Ee7, Ee10, F1a–3; F1p and F3 present or absent) mac; at least five sensilla present (possibly many more), ps not seen but possibly present; 7+7 centro-posterior mes. Abd. V ( Fig. 17 ) with 1–2 anterior (a5–6, a6 present or absent), 3 medial (m2–3, m5) and 6 posterior (p0–1, p3–5 and pp6) mac.

Legs ( Figs 18 – 19 ). Trochanteral organ with about 25 spine-like smooth chaetae ( Fig. 19 ). Tibiotarsus III with slightly ciliate tenent-hair with similar length to unguis, smooth chaeta opposite to tenent-hair present ( Fig. 18 ). Empodial complex with anterior and posterior pretarsal chaetae; unguis with 4 inner teeth (the proximal pair larger than the unpaired medial and distal teeth) and 3 external teeth (one lateral pair plus one small dorsal); unguiculus slightly truncated with smooth edges ( Fig. 18 ).

Abdominal appendages ( Figs 20 – 24 ). Ventral tube anterior face with 2+2 anterior mac plus and 2+2 mes ( Fig. 20 ); posterior face unclear; lateral flap with about 6 slender smooth chaetae (3 more elongated) plus 5 ciliate chaetae ( Fig. 21 ). Distal ventral face of manubrium with 6+6 apical chaetae ( Fig. 22 ). Manubrial plate (dorsal face) with 2–3 pseudopores and 4–6 ciliate chaetae ( Fig. 23 ). Dens normally crenulate. Mucro bidentate with apical tooth smaller than basal, mucronal spine reaching the apex of basal tooth ( Fig. 24 ).

Etymology. The new species was named after June Osborne, the main character of “The Handmaid’s Tale” TV series played by Elisabeth Moss and based on the original novel written by Margaret Atwood, due to her will to endure and fight the oppressive social system in which she lives. June’s character symbolizes the struggle of women in our real society.

Habitat. Specimens of Entomobrya juneae sp. nov. were collected from areas within Atlantic Forest phytogeographic domain, in Extremoz municipality, Rio Grande do Norte State, from sandy soil and dead foliage samples on forested (shaded) sites, during both rainy and dry seasons. According to Köppen-Geiger system, the climate of the area is ‘As’ – equatorial hot with a dry summer, with average annual precipitation of 1.600 mm ( Kottek et al. 2006; Embrapa 2019).

Remarks. Concerning the Neotropical Entomobrya , the new species possibly resembles most E. uambae , E. paroara and somehow the widespread E. atrocincta and E. nivalis (the last two as presented in Katz & Soto-Adames 2015) partially in color pattern and dorsal chaetotaxy, only known for the last two species. Compared to E. uambae and E. paroara the new species differs in presenting the antennae shorter or as long as the trunk (clearly longer in E. uambae and E. paroara ), prelabral chaetae simple (bifurcated in E. paroara ), absence of basal tooth on unguiculus (present in E. uambae ), dens normally crenulate (almost rigid in E. uambae and E. paroara , with few crenulations) and mucro with distal tooth reduced (subequal in E. uambae ). Compared to E. paroara the new species also differs in the presence of the apical bulb on Ant. IV (absent in the first species, see Arlé & Guimarães 1978, pg. 3). This is also the case of E. egleri ( Arlé & Guimarães 1978, pg. 15). This shared condition supports neither species are Entomobrya and suggests both may actually belong to Entomobryoides , even though the legs chaetotaxy and other morphological aspects are unclear for such species (as discussed for Entomobryoides in Jordana 2012 ). A further discussion concerning this topic is presented ahead in the text.

Concerning the dorsal chaetotaxy, the new species can be readily separated from E. nivalis and E. atrocincta especially in: absence of Ps5 mac on head (present in E. atrocincta and E. nivalis ), absence of m5 and p5 mac on Th. II (both present in E. nivalis , p5 present in E. atrocincta ), absence of a2 and a3 mac on Abd. III (both present in E. atrocincta , a3 present or absent in E. nivalis ) and reduction of A series of mac on Abd. IV, with only A6 (with more mac in the other two species). The new species also differs from E. atrocincta and E. nivalis in prelabral chaetae smooth (ciliate in the other two species) and trochanteral organ with about 25 smooth chaetae (about 30 or more in the other two species). The recently described Brazilian Entomobrya bahiana resembles the new species in part of the complexity of head, thorax and Abd. I–III chaetotaxy, but it is remarkably different concerning the color pattern, with trunk almost entirely pigmented, dorsal head with Ps3 and Ps5 and lacking S1 mac (the opposite in E. juneae sp. nov.), presence of m2 plus one multiplet (as mac) on Th. II (both absent in E. juneae sp. nov.) and specially holding a more complex macrochaetotaxy of Abd. IV (reduced in central area of E. juneae sp. nov.). The labial chaetotaxy of both species also differs, and E. bahiana presents R and E ciliated, while the new species present only e as a smooth chaeta. Finally, the trochanteral organ of E. bahiana is reduced (with about 15 chaetae) compared to the new species (about 25). More comparisons among the cited species are presented in Table 1 .

Figures

FIGURE 1. Entomobrya juneae sp. nov.: habitus of a specimen fixed in ethanol (lateral view).

FIGURES 2–6. Entomobrya juneae sp. nov. head: 2, left Ant. IV, dorsal view (apical bulb simple); 3, left Ant. IV, dorso-lateral view (apical bulb apically bilobed); 4, apical Ant. III, ventro-lateral view (right side); 5, right eyepatch; 6, dorsal head chaetotaxy (right side).

FIGURES 7–10. Entomobrya juneae sp. nov. head: 7, labral chaetotaxy; 8, right maxillary palp and sublobal plate; 9, labial chaetotaxy including labial papillae (right side only represents papillae A and C); 10, post-labial chaetotaxy.

FIGURES 11–14. Entomobrya juneae sp. nov. trunk dorsal chaetotaxy (left side): 11, Th. II; 12, Th. III; 13, Abd. I; 14, Abd. II.

FIGURES 15–17. Entomobrya juneae sp. nov. trunk dorsal chaetotaxy (left side): 15, Abd. III; 16, Abd. IV; 17, Abd. V.

FIGURES 18–24. Entomobrya juneae sp. nov. trunk appendages: 18, Empodial complex of leg. III; 19, trochanteral organ; 20, ventral tube anterior face; 21, ventral tube lateral flap (right side); 22, manubrium ventro-distal chaetotaxy; 23, manubrial plate (dorsal side); 24, distal dens and mucro.