Eusarcus marmoreus, Júnior & Ázara & Ferreira, 2021

Júnior, Gilson Argolo dos Santos, Ázara, Ludson Neves de & Ferreira, Rodrigo Lopes, 2021, Three new species of Eusarcus Perty, 1833 (Opiliones, Gonyleptidae) from Brazilian caves, European Journal of Taxonomy 740 (1), pp. 36-54 : 43-47

Eusarcus marmoreus sp. nov.

urn:lsid:zoobank.org:act:39CE9706-C0D6-49A2-9832-FD777C5201CF

Figs 4–6 , 10–11

Diagnosis

Eusarcus marmoreus sp. nov. can be distinguished from all species of the genus by having coxa IV with one transversal, proapical, trifurcated and truncated apophysis, with one dorsal apex higher than the other two ventrally-disposed apices. Eusarcus marmoreus sp. nov. resembles E. berlae (Mello-Leitão, 1932) , E. sergipanus Hara & Pinto-da-Rocha, 2010, E. signatus (Roewer, 1949) and E. sooretamae (Soares & Soares, 1946) by the presence of a proapical truncated apophysis at coxa IV but can be distinguished by the following characters: unarmed scutal area III, low ocularium with a median spine, femur IV with proventral and retroventral rows of acuminate tubercles increasing in size apically and trochanter IV with only one high (taller than trochanter width) promedian apophysis.

Etymology

The specific epithet ʻ marmoreus ʼ means ʻof marbleʼ in Latin and refers to the lithology of the cave where the type specimen was found.

Material examined

Holotype BRAZIL • ♂; Espírito Santo State, Vargem Alta MUnicipality, Caverna Archimides Panssini cave ; 20°41′15.3″ S, 41°03′45.0″ W; 4 Apr. 2014; R.L. Ferreira et al. leg.; ISLA 12968 (destroyed).

Paratypes BRAZIL • 3 ♀♀; same collection data as for holotype; ISLA 66190 to 66192 • 1 ♂; same collection data as for holotype; ISLA 1472 (destroyed) .

Description

Male (holotype, ISLA 12968)

MEASUREMENTS. DSL 4.79, DSW 3.41, femur I 2.72, II 6.27, III 4.08, IV 5.03.

DORSUM ( Fig. 4A, E ). Blunt PAM; acuminate median paracheliceral projection lower than PAM. Low ocularium with median spine (about two times ocularium height). Carapace with scattered granules. Scutal areas I–IV with scattered granules with higher density on scutal areas III–IV. Posterior margin of dorsal scUtUm with scattered granUles. Free tergites I–III with a defined row of granUles. Anal opercUlUm with scattered granules.

VENTER ( Fig. 4B ). Coxa I with irregular row of setiferous tubercles, coxae II–IV densely and irregularly granulate.

CHELICERAE. Segment I with two ectal-basal tubercles fused at the base and one irregular mesal-basal tubercle.

PEDIPALPS. Trochanter with sparse tubercles dorsally. Femur with one mesal apical setiferous tubercle.

LEGS ( Fig. 5 ). Coxae I–III with scattered granules; coxa IV with one transversal, proapical, trifurcated and truncated apophysis, with one dorsal apex higher than the other two ventrally-disposed apices. Trochanters I–IV with scattered tubercles; trochanter IV with one high (taller than trochanter width) promedian apophysis, which is conical, with rounded and anteriorly-curved apex. Femur III with proventral and retroventral rows of acute tubercles increasing in size apically; femur IV slightly sinuous, with small PDS and RDS, with proventral and retroventral rows of acuminate tubercles increasing in size apically. Patellae, tibiae and metatarsi I–IV granUlated withoUt defined armatUre.

COLOURATION (in alcohol) ( Figs 4–5 ). Body and appendages background colour Strong Brown (55), appendages Strong Orange (50).

PENIS ( Fig. 6 ). Ventral plate dorsally concave with substraight lateral margins; distal margin straight; ventral surface entirely covered with type T1 microsetae; with three pairs of lateral-distal MS C1–C3, three wide pairs of A1, one pair of B1, one pair of minute D1, and E1 absent. Stylus smooth, wider at apex, ventrally tilted. Ventral process spatula-shaped, dorsally tilted.

Female (paratype, ISLA 66190)

MEASUREMENTS. DSL 4.73, DSW 2.93, femur I 2.40, II 5.18, III 3.57, IV 4.53.

Similar to male, except for leg IV unarmed with only coxa IV having one short proapical tubercle.

Intraspecific variation

Males (n = 2): DSL 4.79–4.17; DSW 3.41–3.02, femur I 2.72–2.44, II 6.27–6.11, III 4.08–4.20, IV 5.03– 5.12.

Geographical distribution

Known only from the type locality ( Fig. 11 ).

Ecological remarks

Archimides Panssini is a marble cave located in Vargem Alta Municipality (Espírito Santo State, southreastern Brazil). It possesses around 150 meters of horizontal projection, with an irregular topography. The inner cave chamber harboUrs a small amoUnt of water flow. ThUs, organic resoUrces observed in the cave were vegetal debris broUght in by water flow and piles of bat gUano, especially those produced by hematophagous bats. Roots from the external vegetation were also observed in a few areas. Specimens of Eusarcus marmoreus sp. nov. were found freely walking in the inner cave chambers, usually associated with moistened substrates ( Fig. 10B ). The Archimides Panssini Cave is also the type locality of the troglobitic palpigrade Eukoenenia spelunca Souza & Ferreira, 2011 ( Souza & Ferreira 2011), which reinforces its relevance. The cave is located in the Atlantic Forest domain, and the external landscape is topographically heterogeneous. The region presents a Cwa climate according to the Köppen classification system, with an average annUal precipitation ranging from 1000 to 1300 mm and an average annual temperature of 20.9ºC. The external landscape is quite altered, especially due to the removal of native vegetation for crops. Furthermore, many quarries for the extraction of marble were observed in the area during the last visit (in 2014) ( Fig. 10A ), which represents a serious threat for species associated with caves.

Figures

Fig. 4. Eusarcus marmoreus sp. nov., habitus. A–B, E. ♂, holotype (ISLA 12968). C–D, F. ♀, paratype (ISLA 66190). A. Dorsal view. B. Ventral view. C. Dorsal view. D. Ventral view. E–F. Right lateral view. Scale bars: A–E = 1 mm; F = 0.5 mm.

Fig. 5. Eusarcus marmoreus sp. nov., ♂, holotype (ISLA 12968). A–B. Femur IV, dorsal and ventral view, respectively. C–D. Patella and tibia IV, dorsal and ventral view, respectively. E–F. Femur III, dorsal and ventral view, respectively. G–H. Trochanter IV dorsal and ventral view, respectively. Scale bars: A–F = 0.5 mm; G–H = 0.2 mm.

Fig. 6. Eusarcus marmoreus sp. nov., ♂, holotype (ISLA 12968), distal part of penis. A. Dorsal view. B. Ventral view. C. Right lateral view. D. Left lateral view. Macrosetae highlighted in different coloUrs: light blUe = MS A; pUrple = MS B; pink = MS C; yellow = MS D. Scale bars 50 μm.

Fig. 10. A. External landscape of Vargem Alta Municipality, with many quarries for marble extraction. B. Living specimen of Eusarcus marmoreus sp. nov., ♂, holotype (ISLA 12968) from Caverna Archimides Panssini Cave, Vargem Alta Municipality, Espírito Santo State, Brazil. C. Living specimen of Eusarcus xambioa sp. nov., ♂, holotype (ISLA 60386) from Caverna da Explosão Cave, Xambioá Municipality, Tocantins State, Brazil. Photos by R.L. Ferreira.

Fig. 11. Known distribution of Eusarcus capixaba sp. nov., Eusarcus marmoreus sp. nov. and Eusarcus xambioa sp. nov. in Brazil.