Protimesius regalo, Bragagnolo, Cibele, 2013

Bragagnolo, Cibele, 2013, Two new species of Protimesius from northern Brazil (Opiliones: Laniatores: Stygnidae), Zootaxa 3620 (2), pp. 283-292 : 286-288

Protimesius regalo sp. nov.

( Figs. 2 A–G; 4A–C; 5)

Protimesius evelinae (part): Kury et al 2010: 567, fig. 2d (misidentification).

Remarks. Kury et al. (2010), in an expedition to State of Tocantins for the Project “Aracnídeos e Miriápodes da Mata Atlântica” (AMMA) collected several individuals of Stygnidae , identified as Protimesius evelinae Soares & Soares. I have reviewed this material and was able to confirm the misidentification. The specimens are herein designated as paratypes.

Types data: Brazil, Tocantins state, Lajeado (UHE Luis Eduardo Magalhães), IV. 2002, D. Pavan leg. 3 holotype (MZSP 30253); idem, Porto Nacional, (Luzimangue), 13.IV. 2007, A. Kury et al. leg. Paratypes (MNRJ 0 7587, 18 3 10 Ƥ and MZSP 49298 Ƥ).

Etymology. The specific name means “gift” in Italian and refers to Ricardo Pinto-da-Rocha, who kindly offered me the opportunity to study the specimens herein designated as holotype.

Diagnosis: The new species differs from the other species of the genus by the presence of a dorso apical tubercle on fermur IV. It is is similar to P. evelineae Soares & Soares and P. foliadereis Villarreal-Manzanilla & Pinto-da-Rocha, due to the presence of a dorsal and an apical retrolateral row of acute tubercles on male tibia IV. It differs from these species due to the absence of a ventral row of tubercles on male tibia IV, and the presence of two dorsal rows of tubercles on male patella IV.

Description of male holotype (MZSP 30253): Measurements: Dorsal scute length 4.6; prosoma length 2.2; dorsal scute width 3.9; prosoma width 3.7; interocular distance 2.8.

Dorsum ( Fig. 2 A, B): Prosoma: anterior margin with two tubercles on each side; with low and tuberculated anterior eminence. Ocularium and lateral margin smooth. Area I longitudinally divided, with two small tubercles each side. Area II with four small tubercles. Area III with two parallel spiniform apophysis and one row of 2–3 small tubercles on each side near posterior groove. Posterior margin with a row of 11 small tubercles; free tergite I with a row of 12 small tubercles, II with 18, III with 4.

Venter: Coxa I with a median row of nine tubercles, two apical; II with a median row of six tubercles; III and IV irregularly minutely tuberculated. Free sternites I–III with a row of minute granules. Anal plate covered irregularly with minute granules.

Chelicera: Swollen. Segment I smooth; II with one median and three small distal teeth; III with two distal teeth.

Pedipalpus ( Fig. 2 F, G): Coxa with large dorso-basal apophysis and tree ventral pointed tubercles. Trochanter with one ventral and one dorsal tubercles. Femur with one ventro-basal tubercle. Patella unarmed. Tibia mesal IIiII, ectal IIiIi; Tarsus mesal IiIiii; ectal iIiiii.

Legs ( Fig. 2 C–E): Coxa I with two dorsal tubercles; II with one large, anterior and two posterior dorsal tubercles; III with one dorsal apical tubercle; IV dorsally minutely tuberculated. Trochanter I–II smooth, III with two dorsal tubercles; IV with one dorsal and two ventral tubercles. Femora I–III smooth; IV with one dorso-apical spiniform apophysis; one prolatero-apical row of seven tubercles; one retrolateral row of five tubercles on distal part. Patela IV with two dorsal rows of tubercles, one dorsal and one ventroapical spiniform apophysis. Tibia IV with one dorsal row of nine tubercles; one retrolateral row with four spiniform tubercles on distal 2/3; one large bifid retrolateral and one prolateral apical apophysis. Tarsal segmentation: 8:23:6:7.

Penis ( Fig. 4 A–C): ventral plate with lateral and distal margin concave, with two distal pairs of long curved setae and one short pair; three basal pairs of setae; dorsal process present; stylus swollen apically.

Color: In alcohol mostly yellowish brown.

Female. Paratype (MZSP 49298): Measurements: Dorsal scute length 4.7; prosoma length 2.1; dorsal scute width 4.0; prosoma width 3.5; interocular distance 2.5.

Similar to male, except for: chelicera not swollen; prosoma with lower anterior eminence. Pedipalpal tibia mesal IiiIi, ectal IIiIi; tarsus mesal IiIiIi, ectal Iiii. Legs finely granular; femur IV smooth; tibia IV with a small dorsal pointed apical tubercle.

Distribution. State of Tocantins, Brazil.

Biology. Fig. 5 shows an aggregation of Protimesius regalo sp. nov. found under the litter death leaf (Pérez- Gonzáléz, pers. com.), in Porto Nacional, State of Tocantins, Brazil. As recorded for other arthropods (Rasa 1997), harvestmen aggregations are more commonly found during dry and cold periods or in xeric environments, such as Tocantins (central western-Brazil). In this environment, the gregarious habit could have a very important adaptive value, likely reducing evaporation among grouped individuals. Moreover, harvestmen aggregations are generally more frequently found during the day (Machado & Macías-Ordóñez 2007). Likewise, the individuals of Protimesius regalo sp. nov. were aggregated under the litter during the day, and during the night they dispersed for foraging. This behavior was observed also in captivity (A. Pérez-González pers. comm.). For Laniatores, the records of aggregations are restricted to cavities in the ground or tree trunks, inside the caves or under the rocks (see table 11.1 in Machado & Macías-Ordóñez 2007). The only other record of aggregation in Stygnidae is from Protimesius longipalpis (Roewer, 1943) found inside cavities of tree trunks (Machado & Macías-Ordóñez 2007). Thus, this is the second record of aggregation for Stygnidae and, among the Laniatores, the first record found in forest litter.

Figures

FIGURE 2. Protimesius regalo sp. nov., male holotype. A. Dorsal view of body. B Lateral view of body. C – E. Segments of leg IV (C. dorsal view of trochanter-tibia, D. ventral view of trochanter-tibia; E. lateral view of patella and tibia); F and G. Right pedipalpus (F. ectal view, G. mesal view). Scale bars: 1 mm.

FIGURE 4. Distal portion of penis. A – C. Protimesius regalo sp. nov., male holotype (A. dorsal view; B. ventral view; C. lateral view. D – F. Protimesius jirau, sp. nov., male holotype (D. dorsal view; E. ventral view; F. lateral view) Scale bars: 0.1 mm.

FIGURE 5. Aggregation of Protimesius regalo sp. nov. from Porto Nacional, TO. Picture by Abel Pérez-González.