Pararrhopalites iataganii, Souza & Medeiros & Bento & Zeppelini & Bellini, 2024

Souza, Paolla Gabryelle Cavalcante De, Medeiros, Gleyce Da Silva, Bento, Diego De Medeiros, Zeppelini, Douglas & Bellini, Bruno Cavalcante, 2024, New cave species of Cyphoderus Nicolet and Pararrhopalites Bonet & Tellez (Hexapoda, Collembola) from Caatinga biome, Brazil, Zootaxa 5474 (3), pp. 201-224 : 213-219

Pararrhopalites iataganii sp. nov. Souza, Medeiros & Zeppelini

Figs 1 , 8–12 , Table 2

Type material. Holotype male in slide: Brazil, Rio Grande do Norte State, Baraúna, Furna Nova Cave (05°02’03.8”S; 37°34’15.8”W), Aphotic zone, 18/VII/2022, Souza, P.G.C, Santos, N. M. C., Lima, E. C. A., Bento, D. M., Freitas, J. I. M. coll. ( CC / UFRN) . Paratypes: 4 females in slides, same data of holotype ( CC / UFRN) ; 2 females in slides, same data of holotype except ( CRFS / UEPB); and 3 males, 2 females and 1 juvenile in slides, same data of holotype except 18/VIII/2022 ( CC / UFRN) .

Diagnosis. Specimens pale yellow, some individuals with scattered red pigment on dorsal head and body. Antennae shorter than the body length, Ant. IV with 12 subsegments. Eyes 1+1, head interantennal area with 3 reduced, apically rounded sensilla, frontal area with 13 spines. Parafurcal area with 12 chaetae. Ungues without tunica, with a pair of lateral teeth. Manubrium with 6+6 dorsal chaetae, dens with 23 dorsal (posterior) and 9 ventral (anterior) chaetae, ventral formula from the apex to the basis as: 3, 2, 2, 1…1. Mucronal chaeta absent.

Description. Body (head + trunk) average length of the type series 0.75 mm (0.5–1.1 mm), holotype with 0.64 mm, males averaging 0.57 mm (0.5–0.67 mm) (n=4), females averaging 0.83 mm (0.65–1.1 mm) (n=4). Specimens usually pale ( Fig. 8 ), some individuals with scattered red pigment on the dorsal head and large abdomen.

Antennal length in holotype 0.75 mm. Antennal segments ratio I: II: III: IV of the holotype as 1: 2.5: 5.3: 11.5. Ant. IV shorter than body length ( Fig. 8 ). Ant. IV with 12 subsegments, subsegments 1–12 with 4/6/6/7/8/10/10/10/ 10/10/10/26 chaetae, respectively; subsegment 12 with one curved chaeta and one small sensillum at the apex ( Fig. 9A ). Ant. III with 21 chaetae plus one short sensillum (Aai) laterally to the sensory organ; apical organ sensory rods in independent shallow invaginations ( Fig. 9B ). Ant. II with 15 chaetae, 4 of them spine-like, plus 1 rounded apical microsensillum ( Fig. 9C ). Ant. I with 7 chaetae ( Fig. 9C ). Eyes 1+1, unpigmented. Clypeal area a–g series with 6/6/4/4(+1)/5(+1)/4(+1)/3 chaetae, respectively, 1 chaeta present or absent between series d and e; interantennal area with 1 oval organ and 3 reduced, apically rounded sensilla, α and γ series with 1 chaeta each, frontal area A–E series with 2/1/2/2(+1)/2 chaetae, respectively, with a total of 13 frontal spines ( Fig. 9D ). Ventral head with 3 a and 1 b chaetae on the post-labial region, plus 3 elongate oval organs, labial basomedian field with 7 and basolateral field with 2 chaetae, respectively ( Fig. 9E ). Six prelabral chaetae present ( Fig. 9D ), labral p, m, a series with 5, 5, 4 chaetae, respectively, p2 longer than the others; m0 smaller than m1, labral intrusions present, labral papillae absent ( Fig. 9F ). Labial palp with 5 proximal chaetae, with 6 papillae, formula of the guards as: H (2), A (0), B (5), C (0), D (3), E (4) + a lateral process not reaching the apex of the papilla E, 1 papilla B guard-chaeta laterally displaced to C, large, curved and blunt ( Fig. 9G ). Maxillary outer lobe apical chaeta with a basal toothlet, basal chaeta shorter than the apical one, oral fold with 2 chaetae, sublobal plate without chaeta-like appendages ( Fig. 9H ). Mandibles asymmetrical with 5 + 3 apical teeth ( Fig. 9I ). Maxillae globular, without any clear modifications ( Fig. 9J ).

Large abdomen without clear segmentation, constrictions or vesicles. DI-1 row of dorsal spines present on females, absent on males ( Figs 10A–B ). Th. II with 1 a chaeta and 1 m spine. Th. III with 1 a chaeta, 1 m and 1 p spines. Abd. I with 1 chaeta and 1 spine on a and m rows, and 3 p spines. Bothriotricha A, B and C present on Abd. II, slightly misaligned, nearly in a straight line; Abd. II with 2 chaetae, 1 spine on a row, plus bothriotrichum A; 3 chaetae and 1 spine on m row, plus bothriotrichum B; and 5 chaetae on p row, plus bothriotrichum C. Abd. III–IV with 7 chaetae under the bothriotrichum C. Abd. III–IV dorsal spine rows dI-1 with 9 spines in females, row absent in males; dII-1 with 6 spines in females and 8 in males; dIII-1 with 7 spines in females and 6 in males; dIV-1 with 5 spines in females and 4 in males; and dV-1 with 8 in females and 7 in males ( Figs 10A–B ). Parafurcal area with 12 chaetae in both sexes, distributed in 4 rows of 2, 4, 3 and 3 chaetae ( Fig. 10A ). Bothriotrichum D present on the small abdomen of both sexes, with 4 accessory chaetae on females and 3 on males ( Figs 10C–D ). Female dorsal anal valve with as2–4, ams1–3, ms1–3, mps1–3 and ps1–2 chaetae, ams1, ms1 and ps1 unpaired; each ventral anal valve with aai1–3, ai1–4, mi1–2, mpi1–5 and pi1–3 chaetae, ami1 as an oval organ, mi2 bothriotrichum-like and mpi5 as the subanal appendage, smooth and curved towards the anal opening ( Fig. 10C ). Male dorsal anal valve with as2–4, ams1–3, ms1–3, mps1, mps3, and ps1–2 chaetae, ams1, ms1 and ps1 unpaired; each ventral anal valve with aai1–2, ai1–4, mi1–2, mpi1–5 and pi1–3 chaetae, ami1 as an oval organ, mi2 bothriotrichum-like ( Fig. 10D ). Female genital plate with 2+2 chaetae on ventral side ( Fig. 10E ). Male genital plate with about 10+10 chaetae ( Fig. 10F ).

Legs ( Figs 11 , 12A–C ): Epicoxae I–III with 1, 1 and 2 chaetae, respectively. Subcoxa I–III with 0, 1 and 1 chaetae, respectively. Coxae I–III with 1, 2 and 4 chaetae, respectively. Trochanters I–III with 5, 3–5 and 6 chaetae, respectively, trochanter III with one chaeta modified into a thick and bent metatrochanteral spine, trochanters II–III with 1 and 1–2 oval organs, respectively. Femora I–III with 14, 14, 15 chaetae and 1, 1, 1 oval organs, respectively ( Figs 11A–C ). Tibiotarsi I–III with 54, 51, 54 chaetae and 3, 3, 3 oval organs, respectively, distal whorl with 9 chaetae on each leg ( Figs 11D–F ). Foot complexes I–III with 2 pretarsal chaetae each, one of them larger than the other ( Figs 12A–C ). Ungues without tunica, with a single medial inner tooth (larger on unguis III), 2 paired small lateral teeth and 1 dorsal tooth (not seen in unguis III, possibly reduced or absent). Unguiculus I without teeth, unguiculi II–III with a small inner tooth, apical filament slightly surpassing the apex of unguis on leg I, reaching the apex on leg II but not reaching the apex on leg III ( Figs 12A–C ).

Abdominal appendages ( Figs 12D–G ): Collophore with 0+0 or 1+1 chaetae on the lateral flaps, corpus without chaetae. Tenaculum ramus with 3 teeth plus an apically rounded basal appendix, corpus with 1–2 apical chaetae. Manubrium with 6+6 chaetae, all dorsal, one larger than the others ( Fig. 12D ). Dens dorsally (posteriorly) with 23 chaetae, lines E / PE / P / PJ / J with 7/2/1/7/6 chaetae, respectively ( Fig. 12E ), ventrally (anteriorly) with 9 chaetae following the formula from the apex to the basis: 3, 2, 2, 1…1 ( Fig. 12F ). Mucronal lamellae serrated, inner lamella with about 30, outer lamella with about 16 teeth; mucronal chaeta absent ( Fig. 12G ). Ratio manubrium:dens:mucro of the holotype as 1: 3.3: 1.4.

Etymology. The new species honors our dear friend, the biospeleologist José Iatagan Mendes de Freitas, for his indispensable work at the Furna Feia National Park, Rio Grande do Norte, and all other contributions with the National Center for Cave Research and Conservation (CECAV/ICMBio) in prospecting and mapping new caves through Brazil.

Remarks. The combination of Ant. IV with 12 subsegments, 1+1 eyes, head interantennal area with 3 apically rounded sensilla and frontal area with 13 spines, ungues with a pair of lateral teeth, manubrium with 6 dorsal chaetae, dens with 23 dorsal chaetae, with ventral chaetotaxy formula as 3, 2, 2, 1…1, and mucro without chaeta sets Pararrhopalites iataganii sp. nov. apart from all its congeners. Considering the number of eyes (1+1), the new species resembles other Neotropical taxa like P. queirozi Brito, Lima & Zeppelini, 2019 , P. sideroicus Zeppelini & Brito, 2014 and P. wallacei (Zeppelini & Palacios-Vargas, 1995) . However, P. iataganii sp. nov. can be readily separated from them by: Ant. IV with 12 subsegments (vs. 11 or less in the other species), frontal head with 13 spines (15 in P. queirozi , 10 in P. sideroicus and P. wallacei ), 1 frontal cephalic oval organ (2 in P. sideroicus ), manubrium with 6 dorsal chaetae (less in P. queirozi and P. sideroicus , unknown to P. wallacei ), and dens dorsally with 23 chaetae (less in the other species). Further comparisons between the Neotropical species of the genus are summarized in Table 2.

The reduction of pigment and eyes (just 1+1) may be considered troglomorphic traits of P. iataganii sp. nov., since most species of Pararrhopalites have 2+2 or more eyes and at least some of them are pigmented ( Zeppelini & Brito 2014). On the other hand, the species does not show any clear elongation of appendages, ungues or chaetae, features observed as troglomorphisms in some cave Collembola ( Christiansen 1961, 1988; Souza et al. 2022). Specimens of P. iataganii sp. nov. were only found in the aphotic zone of Furna Nova cave, even though other zones of the cave and its aboveground surroundings were investigated.

Habitat, threats and conservation status. Furna Nova cave stands as the exclusive documented habitat of P. iataganii sp. nov., although other caves and surface environments in the region have been surveyed. The cave has relatively large dimensions for the region, with approximately 240 meters of passages mapped thus far, while certain sections remain unexplored ( Fig. 1D ). Notably, the cave features only one small entrance, fostering a stable microclimate characterized by relatively high temperature and humidity levels, alongside limited air circulation. Seasonal occurrences of elevated carbon dioxide concentration are observed at lower cave levels, including areas where individuals of P. iataganii sp. nov. were collected.

The cave primarily maintains occasional drips and small puddles observed in its lower sections. Consequently, the principal organic resources for cave fauna predominantly comprise guano patches, primarily deposited by the hematophagous bats Desmodus rotundus and Diphylla ecaudata , the Brazilian funnel-eared bat Natalus macrourus (Gervais) , an insectivore, and the omnivorous bat Phyllostomus discolor ( Vargas-Mena et al. 2018) .

Furna Nova cave is situated within the Furna Feia National Park, designated in 2012 to safeguard a notable cluster of caves and the biodiversity of the Caatinga biome ( Brasil 2012). While the area of the National Park itself is well conserved, its periphery has undergone substantial changes, mainly due to irrigated agriculture. Nonetheless, these anthropogenic influences are situated at a considerable distance from the cave and do not seem to exert any discernible impact on its subterranean environments.

Furna Nova is among the caves within the Furna Feia National Park slated for tourism. However, these visits will be conducted in an organized manner and based on studies that have considered the significance and uniqueness of its cave fauna. Notably, the lower cave level, where P. iataganii sp. nov. is found, will be off-limits to visitors, and there are plans for monitoring the bat community. Consequently, the newly discovered species could potentially be classified as Least Concern (LC) according to the International Union for Conservation of Nature’s method for assessing the risk of extinction ( IUCN 2022).

Figures

FIGURE 1. Distribution of the sampled caves: A, Map of Brazil marking Rio Grande do Norte state and the sampled municipalities; B, Baraúna municipality, the blue circle marks the location of Furna Nova Cave inside Furna Feia National Park (delimited by the black line), the type locality of Pararrhopalites iataganii sp. nov.; C, Felipe Guerra municipality, the white circle marks the location of Boa Cave within a semiarid forest, the type locality of Cyphoderus caatinguensis sp. nov.; D, Furna Nova cave first hall near to the entrance, the specimens of P. iataganii sp. nov. were found in the dark zone of this cave, which was much darker than it appears in the image; E, Boa cave, the image displays piles of guano near to the speleologists, depicting one of the regions of the cave sections, where the specimens of C. caatinguensis sp. nov. were collected.

FIGURE 8. Pararrhopalites iataganii sp. nov. live specimen in its natural habitat. Photograph by Diego Bento (2021).

FIGURE 9. Pararrhopalites iataganii sp. nov. head: A, Right Ant. IV, dorsal view, in detail the apical curved chaeta and sensillum; B, Left Ant. III, ventral view, black arrow marks the lateral short sensillum; C, Dorsal view of the left Ant. I–II, black arrows mark the spine-like chaetae; D, Anterior head chaetotaxy and eyes, white arrow marks a chaeta which can be absent; E, Ventral head, right side, with labial basomedial and basolateral labial chaetae and post-labial region; F, Labral chaetotaxy; G, Labial palp, left side; H, Maxillary outer lobe and sublobal plate (right side); I, apical teeth of the mandibles; J, Maxilla capitulum, right side.

FIGURE 10. Pararrhopalites iataganii sp. nov. trunk lateral view: A, Large abdomen chaetotaxy of a female; B, Dorsal spines of the posterior male large abdomen; C, Female anal valves chaetotaxy, ‘*’ mark unpaired chaetae; D, Male anal valves chaetotaxy, ‘*’ mark unpaired chaetae E, Female genital plate; F, Male genital plate.

FIGURE 11. Pararrhopalites iataganii sp. nov. legs: A, Epicoxa to femur of leg I; B, Epicoxa to femur of leg II (arrows indicate chaetae present or absent); C, Epicoxa to femur of leg III (arrows indicates oval organ present or absent); D, tibiotarsus I; E, tibiotarsus II; F, tibiotarsus III.

FIGURE 12. Pararrhopalites iataganii sp. nov. trunk appendages: A–C, Foot complex I–III; D, Manubrium, dorso-lateral view; E, Dens, dorsal chaetotaxy; F, Dens, ventral chaetotaxy of the dens. G, Mucro, external view.