Cyphoderus caatinguensis, 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 : 204-211

publication ID	https://doi.org/ 10.11646/zootaxa.5474.3.1
publication LSID	lsid:zoobank.org:pub:8195C49D-7E8A-4363-9F43-0268144AA946
DOI	https://doi.org/10.5281/zenodo.12567636
persistent identifier	https://treatment.plazi.org/id/50728799-0C3B-4C3E-B9C0-6B4FFA87F871
treatment provided by	Plazi
scientific name	Cyphoderus caatinguensis
status	sp. nov.

Treatment

Cyphoderus caatinguensis sp. nov. Souza, Bellini & Zeppelini

Figs 1 View FIGURE 1 , 3–7 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 , Table 1

Type material. Holotype male in slide: Brazil, Rio Grande do Norte State, Felipe Guerra, Caverna Boa (05°33’59.5”S; 37°41’52.4”W), Aphotic zone, 21/VII/2022, Souza, P.G.C, Santos, N. M. C., Lima, E. C. A., Bento, D. M., Freitas, J. I. M. coll. ( CC / UFRN) GoogleMaps . Paratypes: 1 female in slide, same data of holotype ( CC / UFRN) GoogleMaps ; 5 females and 1 juvenile in slide, same data of holotype except 23/VII/2019, Souza, P.G.C, Bellini, B. C., Santos, N. M. C., Bento, D. M., Freitas, J. I. M. coll. ( CC / UFRN); and GoogleMaps 2 females in slides, same data of holotype except 23/VII/2019, Souza, P.G.C, Bellini, B. C., Santos, N. M. C., Bento, D. M., Freitas, J. I. M. coll. ( CRFS / UEPB) GoogleMaps .

Diagnosis. Mandibles normal, not modified. Labial papilla E lateral process finger-shaped, surpassing the apex of the papilla. Labial basal chaetae formula as: m, e, l1–2, a1–5, l2 reduced to a minute smooth chaeta, r chaeta absent. Dorsal head with five antennal macrochaetae (f1–5), A0 macrochaeta present, Pa5 as mesochaeta, other chaetae as microchaetae. Abd. IV with one internal and one external macrochaetae (B4 and E3, respectively). Trochanteral organ with 16–19 spine-like smooth chaetae. Ungues with 4 inner teeth, basal pair asymmetrical (basal posterior tooth much larger than basal anterior one), unpaired apical tooth long and filamentous, tenent hairs capitate. Collophore posterior side with 3 ciliate chaetae (1 unpaired), 2 smooth small spines and 1–3 long, smooth distal chaetae. Dens dorsally with 8–10 inner and 8 outer feathered chaetae. Mucro short and with 4 teeth, belonging to tridenticulati group, with teeth formula as: aAi.

Description. Body length (head + trunk) of specimens 1.2–2.16 mm (n = 5), holotype 1.87 mm, male with 1.87 mm, females with 1.2–2.16 mm (n= 4). Habitus typical of the genus, specimens totally unpigmented. Scales covering Ant. I–II, ventral and dorsal head, dorsal trunk, lateral and ventral manubrium and dens. Legs and collophore without scales.

Antennae shorter than the body length. Antennae segments ratio I: II: III: IV of the holotype as 1: 2.36: 1.81: 3.91. Ant. IV without apical bulb, with ciliate chaetae and at least three types of sensilla (types ‘2’ and ‘3’, elongated sensillum; type ‘4’, finger-shaped sensillum; type ‘10’, minute sensillum with rounded apex, sensu Jantarit et al. 2014). Ant. III with 2 sensory rods (type ‘7’ sensu Jantarit et al. 2014) and 2 guard sensilla (type ‘5’ sensu Jantarit et al. 2014). Ant. II with dorsal scales and at least 4 types of sensilla (types ‘2’, ‘3’, ‘4’ and ‘9’). Ant. I with dorsal scales, multiciliate chaetae and 3 smooth chaetae ( Fig. 3A View FIGURE 3 ). Prelabral chaetae smooth, labral chaetotaxy with 4 (a1–2), 5 (m0–2, m2 shorter than m1) and 5 (p0–2) smooth chaetae, labral papillae absent ( Fig. 3B View FIGURE 3 ). Clypeal formula with 4 (l1–2), 2 (ft) and 3 (pf0–1) smooth chaetae, pf0 slightly longer than pf1 ( Fig. 3B View FIGURE 3 ). Mandibles regular, without modifications, asymmetrical, with 5+4 teeth ( Fig. 3C View FIGURE 3 ). Maxillae capitulum globular, without any clear modifications. Labial palp with 6 papillae, formula of the guards as: H (2), A (0), B (5), C (0), D (4), E (4) + a lateral process finger-shaped and surpassing the apex of papilla E ( Fig. 4D View FIGURE 4 ). Outer lobe of maxilla with the basal chaeta longer than the apical one, both smooth, sublobal plate with one chaeta-like appendage, oral fold with 2 smooth chaetae ( Fig. 3E View FIGURE 3 ). Labial basolateral and basomedian fields with chaetae m, e, l1–2 and a1–5 all smooth, l2 reduced to a minute chaeta, r chaeta absent, 5 labial proximal chaetae (lpc), all smooth ( Fig. 3F View FIGURE 3 ). Ventral postlabial formula of the anterior chaetae as: 4 (G1–4), 2 (X, X4), 4 (H1–4), and 2 (J1–2) chaetae, chaeta X strongly reduced and smooth, posterior region with 2–3 basal chaetae ( Fig. 3F View FIGURE 3 ). Dorsal head chaetotaxy with 5 antennal macrochaetae (f1–5), 1 anterior macrochaeta (A0) and 4 microchaetae (A1–3, A5), 4 medial microchaetae (M1–4), 6 sutural microchaetae (S0, S2–5), 2 post-sutural microchaetae (Ps2, Ps5), 4 postero-anterior chaetae (Pa2–3 as microchaetae, Pa5 as mesochaeta, Pa as the post-ocular bothriotrichum), plus 1 microchaeta of uncertain homology, 2 postero-medial microchaetae (Pm1–Pm3), 6 post-occipital posterior microchaetae (Pp1?, Pp3–7) and 1 postero-external (Pe3) microchaeta ( Fig. 3G View FIGURE 3 ).

Central macrochaetae formula from Th. II to Abd. IV as: 0,0|0,1,0,1, sensilla formula (Th. II–Abd. V) as: 1,1|0,1,1,+,3, microsensilla formula as: 1,0|1,0,1,0,0. Th. II without macrochaetae other than those in the anterior collar, with 3–4 anterior (a2, a3?, a5 plus one microchaeta of uncertain homology), 6 medial (m1–2, m4–m6e?), 6–7 posterior (p1–p6e) microchaetae ( Fig. 4A View FIGURE 4 ). Th. III with 3 anterior (a2, a6–a7), 4 medial (m6–m6p, m7–m7e) and 4 posterior (p2–4, p6) chaetae ( Fig. 4B View FIGURE 4 ). Abd. I with 1 ms and 5 medial (m2–m6) microchaetae ( Fig. 4C View FIGURE 4 ). Abd. II with 5 anterior (a2i, a2, a5–7), 6 medial (m2–3, m3e, m3ep, m6–7) and 2 posterior (p5, p7) chaetae, m2 and a5 as bothriotricha, a2i, a2, and m3e as their accessory chaetae ( Fig. 4D View FIGURE 4 ). Abd. III with 5 anterior (a2i, a2, a5–7), 9 medial (m2–3, m3e, m3e2, m5, am6, pm6, m7i–m7) and 3 posterior chaetae (p6–7 plus one microchaeta without clear homology), a5, m2, and m5 as bothriotricha, a2, m3e, m3e2 and 2–4 extra ones as their accessory chaetae ( Fig. 4E View FIGURE 4 ). Abd. IV with chaetae formula as: 4 ‘ A ’ (A3–A6), 4 ‘ B ’ (B3–B6, B4 as macrochaetae), 4–5 ‘ C ’ (C1–4), 7 ‘T’ (T1–7), 3 ‘ D ’ (D1–3), 4 ‘ E ’ (E1–4, E3 as macrochaetae), 3 ‘ F ’ (F1–3) and 3 ‘ Fe ’ (Fe2–4); 1 posterior (ps) and at least 2 internal sensilla, posterior region with 5 transversal mesochaetae and 3–4 pseudopores ( Fig. 5A View FIGURE 5 ). Abd. V with 5 anterior (a1, a3, a5–6e), 3 medial (m2–3, m5) and 4 posterior (p1, p3–5) main mesochaetae ( Fig. 5B View FIGURE 5 ).

Trochanteral organ with 16–19 smooth spine-like chaetae ( Figs 6A–B View FIGURE 6 ), femur III with several smooth spine-like chaetae similar to those of the trochanteral organ ( Fig. 6B View FIGURE 6 ). Tibiotarsi I–III with an internal row of finely ciliate, abruptly pointed macrochaetae ( Fig. 6C View FIGURE 6 ). Ungues with 4 inner teeth, 2 paired basal asymmetrical (basal posterior tooth remarkably larger than basal anterior tooth), 1 unpaired median and 1 unpaired apical tooth longer than the median tooth and filamentous; ungual outer side with one pair of lateral teeth and 1 unpaired dorsal tooth ( Figs 6D–F View FIGURE 6 ). Unguiculi wing-shaped, with 4 smooth lamellae, anterointernal lamella with a large tooth ( Fig. 6D View FIGURE 6 ). Tenent hairs capitate, longer than the inner distal smooth chaeta on tibiotarsus III ( Fig. 6D View FIGURE 6 ).

Anterior face of collophore ( Figs 7A–C View FIGURE 7 ) with 2–3 ciliate chaetae, none of them clearly thicker than the others ( Fig. 7A View FIGURE 7 ), posterior face with 3 ciliate chaetae (1 unpaired), 2 smooth small spines and 1–3 long, smooth chaetae ( Fig. 7B View FIGURE 7 ). Lateral flap with 2 smooth chaetae ( Fig. 7C View FIGURE 7 ).

Dorsal side of manubrium with about 60+60 chaetae. Manubrial plate with 2 chaetae and 2 pseudopores ( Fig. 7D View FIGURE 7 ). Dens dorsally with 8–10 inner and 8 outer feathered chaetae, with regular ciliate chaetae between the feathered ones; 1 inner smooth or ciliate chaeta near mucro (i1); apex of dens with 1 long, robust feathered chaeta, at least twice as long as the mucro length ( Fig. 7E View FIGURE 7 ). Mucro of the tridenticulati group, teeth formula as aAi, apical tooth (a) followed by a well-developed tooth (A) plus two paired reduced teeth (i) on the inner and outer lamellae ( Fig. 7F View FIGURE 7 ). Ratio of mucro:dens:manubrium of holotype = 1:5.7:7.83.

Etymology. The species is named after the Caatinga biome, where Boa cave is located.

Remarks. The new species is unique within the genus by the combination of the following characters: ungues basal posterior tooth much larger than basal anterior tooth, unpaired apical tooth present, long and filamentous, tenent hairs capitate; femur III with smooth spine-like smooth chaetae; posterior face of collophore with 3 ciliate chaetae (1 unpaired), 2 small, smooth spines and 1 long, smooth distal chaeta; dens dorsally with 8–10 inner and 8 outer feathered chaetae; mucro short, of the tridenticulati group, with tooth formula as: aAi sensu Delamare-Deboutteville (1948).

Cyphoderus caatinguensis sp. nov. resembles other Neotropical species of the tridenticulati group with similar mucronal teeth formula (aAi or aAA). However, the new species can be distinguished from all of them by the combination of the presence of a single m chaeta on the labial basomedian field and a reduced spiny l2 on the basolateral field, one central macrochaeta on the Abd. IV, ungues with an unpaired apical tooth, long and filamentous, and dens dorsal chaetotaxy (see Table 1). Considering the mucronal morphology and labial and Abd. IV chaetotaxy, C. manuneru Bernard, Soto-Adames & Wynne, 2015 is arguably the closest Neotropical species to Cyphoderus caatinguensis sp. nov., but they can be distinguished from each other by the number of spine-like chaetae on the trochanteral organ (16–19 in C. caatinguensis sp. nov. vs. 10 in C. manuneru ), absence of the ungual unpaired apical tooth in C. manuneru (present and filamentous in the new species), tenent hair shape (capitate in the new species vs. acuminate in C. manuneru ) and number of the inner and outer dorsal feathered chaetae on dens (8–10 + 8 in C. caatinguensis sp. nov. vs. 4 + 7 in C. manuneru ). Further comparisons between the Neotropical species of the tridenticulati group are provided in Table 1.

It is noteworthy the new species’ absence of pigments and eyes do not constitute any troglomorphism, since such morphology is shared among all Cyphoderini , which can live in many different habitats, including epigeic environments ( Delamare-Deboutteville 1948; Thibaud & Najt 1987; Oliveira et al. 2023). On the other hand, the strong modifications of the inner teeth seen in the ungues of C. caatinguensis sp. nov. may actually represent troglomorphic traits, as discussed by Christiansen (1961), despite the new species having tenent hairs capitate, a feature that suggests an edaphic life form. We sampled the entrance of the Boa cave and its external surroundings, as well as several other caves in the region, and did not find any specimens of the new species. This absence provides good evidence of a troglobitic species with a very restricted distribution.

Habitat, threats and conservation status. Boa cave stands as the sole documented habitat of Cyphoderus caatinguensis sp. nov. It boasts relatively expansive dimensions for the region, spanning approximately 340 meters in length and encompassing a volume exceeding 10,000 m 3 ( Fig. 1E View FIGURE 1 ). However, its access is limited by a narrow, vertical entrance situated at the base of a sinkhole. Consequently, the microclimate within the cave is characterized by elevated temperatures, high humidity, and remarkable stability.

This cave has only a small isolated subterranean stream present at its lowest level. Consequently, the primary organic resources for cave fauna consist of extensive patches of guano deposited by thousands of Chiroptera , including the hematophagous hairy-legged vampire bat ( Diphylla ecaudata Spix ) common vampire bat ( Desmodus rotundus (Geoffroy Saint-Hilaire)) , the frugivorous flat-faced fruit-eating bat ( Artibeus planirostris (Spix)) and the omnivorous pale spear-nosed bat ( Phyllostomus discolor Wagner ) ( Vargas-Mena et al. 2018).

Although Boa Cave and its immediate environs exhibit a relatively preserved state, the limestone outcrop housing the cave has undergone significant alteration owing to irregular limestone mining activities. Furthermore, there are additional areas in the vicinities which have been impacted, mainly due to deforestation and agricultural practices. However, these alterations are situated at a distance from the cave, and it cannot be definitively stated that they are adversely affecting its fauna. Consequently, due to the uncertainties regarding the potential impacts of these human activities on C. caatinguensis sp. nov. could be classified for now as a Data Deficient (DD) species, according to the International Union for Conservation of Nature’s method for assessing the risk of extinction ( IUCN 2022).