Sphaeridia piauiensis Medeiros & Bellini, 2023

Medeiros, Gleyce da Silva, Silva, Clecio Danilo Dias da, Franca, Josemaria Silva de, Godeiro, Nerivania Nunes & Bellini, Bruno Cavalcante, 2023, Two new species of Sminthurididae (Hexapoda, Collembola, Symphypleona) from Brazil with notes on Denisiella Folsom & Mills and Sphaeridia Linnaniemi, ZooKeys 1173, pp. 1-41 : 1

Sphaeridia piauiensis Medeiros & Bellini sp. nov.

Figs 6 , 7 , 8 , 9 , 10 , 11 , 12

Type material.

Holotype male on slide, Brazil, Piauí state, Piracuruca municipality, Sete Cidades National Park, 'Primeira Cidade’ (4°05'42.53"S, 41°40'50.7"W), 168 m, in sandy soil, ecotonal zone between Caatinga and Cerrado biomes, 14/V/2021, A.M.N. Silva col., pitfall traps. Paratypes on slides: one male, one female, and one juvenile, with the same data of the holotype.

Diagnosis.

Male specimens with a pale purple body, antennae dark purple (Fig. 6A ). Males Ant II with two spiniform microsensilla plus six long chaetae other than b1, Ant III with two or three spiniform microsensilla plus four long chaetae other than c3. Head without any medial chaeta, with 1+1 zones without cuticular granulation between the antennae. Medial prelabral chaetae longer than others in both sexes. Femur I and III with two and one curved chaetae, respectively. Tibiotarsus III of males with a IIpe chaeta leaf-shaped inserted in a large papilla (Fig. 6B ), tibiotarsus III of females with Ipi, IIpi, IIIpi, and IVpi chaetae serrated. Ungues I-III without tunica or pseudonychia. Dorsal anal valve with three unpaired chaetae (as1, ms1, and ps1). Parafurcal area with seven chaetae. Tenaculum with 1+1 chaetae. Ventral tube in males highly modified with several apical processes, two of them in the posterior region lamellated (striated), with 1+1 chaetae (Fig. 6C ), female ventral tube with 1+1 apical vesicles plus 1+1 chaetae (Fig. 6D ). Dorsal dens with a basal appendage (Fig. 6E ), J1-3 and E1 chaetae spiniform, ventral formula as 2,3,2...1 from the apex to the basis.

Description.

Body (head + trunk) length of the type series ranging between 228 and 571 µm, holotype with 269 µm, male average size = 248 µm, female average size = 280 µm, entire type series average size = 259 µm. Male specimens with a pale purple body, antennae dark purple (Fig. 6A ). Female color pattern unknown (studied specimen already on a glass slide).

Head (Figs 7 , 8 ). Antennae length 202 µm in the holotype. Holotype antennal segment ratio I:II:III:IV as 1:2.3:1.7:5.9. Males’ antenna: Ant I with six chaetae (Fig. 7A ). Ant II with element b1 as a thick spine in a large papilla, plus 16 regular chaetae, six of them longer than others (three of them on basal half and three of them on distal half), plus two spiniform microsensilla (Fig. 7A ). Ant III with element c3 present as a thick spine in a papilla, plus 12 regular chaetae, four of them longer than others (two on basal half and two on distal half), plus two or three spiniform microsensilla; apical organ sensory rods in two independent shallow invaginations (Fig. 7A ). Ant IV longer than Ant III, undivided, with ~ 61 chaetae, ~ 8 of them as a curved subapical sensilla (Fig. 7B ). Females’ antenna: Ant I with six chaetae (Fig. 7C ). Ant II with 10 chaetae (Fig. 7C ). Ant III with 10 chaetae, plus one apical spiniform microsensilla; apical organ sensory rods in two independent shallow invaginations (Fig. 7C ). Ant IV longer than Ant III and undivided, with ~ 54 chaetae, ~ 7 of them as curved subapical sensilla (Fig. 7D ). Head capsule (both sexes): Eyes 8+8 plus one interocular chaeta, head capsule normal (not elongated) (Fig. 8A ). Clypeal area a-f lines with 3/6/3-4/4/4/5 dorsal + ventral chaetae, respectively (Fig. 8A, B ). Interantennal area α and β lines with 2/2 chaetae, respectively; frontal area A-E lines with 1/1/1-2/1/2 chaetae, respectively; 1+1 interocular chaetae present; 1+1 zones without cuticular granulation present between the antennae (Fig. 8A ). Labial basomedian and basolateral fields with three chaetae each (Fig. 8C ). Six prelabral chaetae present, medial chaetae longer and thicker than the others (Fig. 8C ); labral p, m, and a lines with 4, 5, 4 chaetae, respectively; each chaeta of a line in an individual papilla (Fig. 8D ). Mandibles normal (not elongated), with 4+5 incisive apical teeth (Fig. 8E ). Maxillae and labial palp papillae unclear. Anterior head, labrum, labium, and visible mouthparts without any clear sexual dimorphism.

Trunk (Figs 9 , 10 ). Large abdomen: thorax continuous with the abdomen, without clear segmentations in both sexes. Males: Th II with one a chaeta inside a cavity and two m chaetae; Th III with two a and two m chaetae; Abd I without chaetae, Abd II with bothriotricha A, B, and C slightly misaligned, with two a, three m, and three p regular chaetae near the bothriotricha; Abd III-IV with three main lines of chaetae above the bothriotrichum C: dII-1 with five, dIII-1 with five, dV-1 with three, plus two lateral chaetae under the bothriotrichum C (Fig. 9A ). Parafurcal area with four rows of chaetae with two, two, one, and two (total of seven) chaetae, neosminthuroid chaetae absent (Fig. 10A ). Females: Th II with one a chaeta inside a cavity and two m chaetae; Th III with two a and two m chaetae; Abd I without chaetae, Abd II with bothriotricha A, B, and C slightly misaligned, with two a, three m, and three p regular chaetae near the bothriotricha; Abd III-IV with four main lines of chaetae above the bothriotrichum C: dI-1 with seven, dII-1 with five, dIII-1 with five, dV-1 with three, plus two lateral chaetae under the bothriotrichum C (Fig. 9B ). Parafurcal area with four rows of chaetae with two, two, one, and two (total of seven) chaetae, neosminthuroid chaetae absent (Fig. 10C ). Small abdomen: including Abd V-VI in both sexes. Males: Abd V with bothriotricha D and E present, plus two regular chaetae. Dorsal anal valve with as1-3, ms1-3, and ps1-2 chaetae, as1, ms1, and ps1 unpaired; each ventral anal valve with aai1, ai1-3, ami1 (as an oval organ lacking any inner sensillum), mi1-2, mpi1, and pi1-3 chaetae (Fig. 10B ). Females: Abd V with bothriotricha D and E present, plus two regular chaetae. Dorsal anal valve with as1-3, ms1-3, and ps1-2 chaetae, as1, ms1, and ps1 unpaired; each ventral anal valve with aai1, ai1-3, ami1 (as an oval organ lacking any inner sensillum), mi1-3, mpi1, and pi1-3 chaetae (Fig. 10C ). Genital plate chaetotaxy unclear in both sexes.

Abdominal appendages (Fig. 11 ). Ventral tube in males symmetrical, with at least three anterior projections and at least eight posterior projections, two of them lamellated (striated), with 1+1 distal chaetae on lateral flaps (Fig. 11A ), females with 1+1 vesicles and 1+1 distal chaetae (Fig. 6D ). Tenaculum ramus with three teeth, each plus an apically rounded basal appendix, corpus with 1+1 chaetae. Manubrium with four dorsal chaetae (Fig. 11B ); dens with a basal appendage and 15 dorsal (posterior) chaetae, lines E/P/PJ/J with 2/2/8/3 chaetae, respectively; J line and E1 chaeta as thick acuminated spiniform chaetae (Fig. 11D ); dens ventrally (anteriorly) with eight chaetae, following the formula from the apex to the basis: 2,3,2...1 (Fig. 11C ). Mucro narrow with a broad apex, with an external lamella smooth and an internal lamella serrated with ~ 22 teeth; mucronal chaeta absent (Fig. 11D ). Furca without any clear sexual dimorphism. Manubrium:dens:mucro ratio of the holotype = 3.3:6.4:1.

Legs (Fig. 12 ). Leg I: coxa with one chaeta; trochanter with two chaetae; femur with 11 chaetae, two of them as curved chaetae; tibiotarsus with 34 chaetae and two oval organs (O2pe, O2ae), whorls I/II/III/IV/V with 9/8/7/5/5 chaetae respectively (Fig. 12A, B ). Leg II: coxa with one chaeta; trochanter with two chaetae; femur with 10 chaetae; tibiotarsus with 34 chaetae and two oval organs (O2pe, O2ae), whorls I/II/III/IV/V with 9/8/7/5/5 chaetae, respectively (Fig. 12C, D ). Leg III: coxa with two chaetae; trochanter with four chaetae; femur with 11 chaetae, one as a short curved chaeta; tibiotarsus in males with 36 chaetae and two oval organs (O2pe, O2ae), chaeta IIpe leaf-shaped in a papilla plus two regular chaetae, whorls I/II/III/IV/V with 9/9/7/6/5 chaetae respectively (Fig. 12E, F ); tibiotarsus in females with 35 chaetae and two oval organs (O2pe, O2ae), chaetae Ipi, IIpi, IIIpi and IVpi serrated, whorls I/II/III/IV/V with 9/8/7/6/5 chaetae respectively (Fig. 12G ). Oval organs of all tibiotarsi in both sexes with a tiny inner sensillum, each (not represented in the figures). Foot complexes: pretarsi I-III with anterior and posterior chaetae each; ungues I-II more slender than the unguis III, with one dorsal unpaired tooth and one internal unpaired tooth, ungues without tunica and pseudonychia; unguiculi I-III without teeth, with all lamellae smooth, unguiculi filament pre-apical and reaching the apex of the ungues in legs I and II, absent in leg III; ratio of ungues I-III in the holotype = 1:0.97:0.96.

Etymology.

The species was named after its type locality, Piauí State, Brazil.

Remarks.

Sphaeridia piauiensis sp. nov. belongs to the Sphaeridia irmleri group sensu Bretfeld and Gauer (1994) due to its complex male ventral tube without asymmetrical structures or medial processes. The Sphaeridia irmleri group holds only three Neotropical species: S. irmleri Bretfeld & Gauer, 1994, S. fibulifera Bretfeld & Gauer, 1994, and S. peruensis Bretfeld & Schulz, 2012. Although they resemble S. piauiensis sp. nov. by the complex male ventral tube, S. irmleri and S. fibulifera males have a smooth and long chaeta IIpe on tibiotarsus III, while males of S. piauiensis sp. nov. and S. peruensis have a leaf-shaped IIpe chaeta. Regarding the tibiotarsal chaetotaxy, S. piauiensis sp. nov. differs from S. peruensis by presenting the tibiotarsus III IIIpi chaeta of normal shape in males and ventral tube with 1+1 chaetae, while S. peruensis presents tibiotarsus III IIIpi chaeta forked in males and the absence of ventral tube chaeta. Also S. peruensis presents two pairs of hooks on the furca (a pair on the manubrium and another on the dens), while they are absent in S. piauiensis sp. nov. The leaf-shaped chaeta on the tibiotarsus III of the male is also seen in the Brazilian species S. heloisae Arlé, 1984, but this species belongs to the brevipila group due to the presence of a posterior medial process on the male ventral tube, absent in S. piauiensis sp. nov. The female of S. piauiensis sp. nov. presents the tibiotarsus III chaeta Ipi toothed, which makes it the sole species from the Neotropical Region with such recorded morphology. Additionally, the new species does not present the chaeta p0 in the labral region (Fig. 8C ), something unusual to other Symphypleona genera. However, this information is mostly undescribed for other species of Sphaeridia , so it is not clear if it has any value as a specific diagnostic trait.

Figures

Figure 6. Sphaeridia piauiensis sp. nov. A habitus of a male in ethanol (dorsal view) B leaf-shaped chaeta on dorsal tibiotarsus III of a male C male ventral tube (apex) D female ventral tube (apex), arrow points to a vesicle E female dens, arrow points to the basal appendage.

Figure 7. Sphaeridia piauiensis sp. nov. antenna (dorsal view) A, B male antenna A Ant I-III B Ant IV C, D female antenna C Ant I-III D Ant IV.

Figure 8. Sphaeridia piauiensis sp. nov. head A male anterior head chaetotaxy (eyes omitted), arrow points to a chaeta which can be present or absent B male labial and post-labial (ventral) chaetotaxy C male labral chaetotaxy D male mandibles apexes (incisive teeth).

Figure 9. Sphaeridia piauiensis sp. nov. large abdomen A male B female.

Figure 10. Sphaeridia piauiensis sp. nov. parafurcal area and small abdomen A male parafurcal area B male small abdomen C female parafurcal area and small abdomen.

Figure 11. Sphaeridia piauiensis sp. nov. male abdominal appendages A ventral tube (lateral view) B manubrial chaetotaxy (lateral view) C ventral dens chaetotaxy D dorsal dens chaetotaxy and mucro.

Figure 12. Sphaeridia piauiensis sp. nov. male legs A coxa, femur, and trochanter of leg I B tibiotarsus and empodial complex of leg I C coxa, femur, and trochanter of leg II D tibiotarsus and empodial complex of leg II E coxa, femur and trochanter of leg III F tibiotarsus and empodial complex of leg III G tibiotarsus and empodial complex of leg III of the female.