Stygnus magalhaesi , Pinto-Da-Rocha, Ricardo & Tourinho, Ana Lúcia, 2012

Pinto-Da-Rocha, Ricardo & Tourinho, Ana Lúcia, 2012, Two new genera, ten new species and new records of Amazonian Stygnidae Simon, 1879 (Opiliones: Laniatores), Zootaxa 3340, pp. 1-28: 19-20

publication ID 10.5281/zenodo.281385

persistent identifier

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scientific name

Stygnus magalhaesi

sp. nov.

Stygnus magalhaesi  sp. nov.

( Figs. 9View FIGURE 9 A –E, 15 D –F)

Diagnosis: This species differs from other member of Stygnus  by the small tubercles on free tergites (larger at least on III in all described species), and tarsus III –IV with scopulae (only present in S. gertschi (Roewer, 1963 ))  , flattened and depressed (both characteristics convergent with Heterostygninae).

Type locality: Brazil, Amazonas, São Gabriel da Cachoeira (Pico da Neblina  , 2,400 m.a.s.l.).

Type material: All material collected in Brazil, Amazonas, São Gabriel da Cachoeira (Pico da Neblina  ). Holotype, male, 2400 m.a.s.l., 11.X. 2007, A.Nogueira leg. (INPA-OP 1025). Paratypes, same locality as holotype: 2400 m.a.s.l., 9.X. 2007, D. Candiani leg., male, female (INPA-OP 1026); 2000 m.a.s.l., 7.IX. 2007, A. Nogueira leg., female (INPA-OP 1027); 2000 m.a.s.l., 6.X. 2007, A. Nogueira leg., female (INPA-OP 1028); 2400 m.a.s.l., 9.X. 2007, N. Lo Man Hung leg., male (MZSP- 36574); 2000 m.a.s.l., 6.X. 2007, A. Nogueira leg., male (INPA-OP 1029).

Etymology: Named after Célio Magalhães Filho, vice-curator of the invertebrates collection at INPA, who has been supporting and supervising the early arachnological group activities at INPA.

Male description (holotype): Measurements: DSL 4.6; PL 1.9; DSW 3.9; PW 3.3; ID 2.1; chelicera II 4.9; III 2.1; pedipalpus 9.2; leg I 10.3; II 20.6; III 14.9; IV 19. 3.

Dorsum ( Fig. 9View FIGURE 9 A –B): Anterior margin with two small tubercles each side. Prosoma with one spine slightly frontwards, with smooth base. Lateral margin with one row of small tubercles from coxa II to groove IV. Eye mounds with one –two small tubercles. Area I with one tubercle each side; II smooth; III with two divergent spines backwards, with smooth base, one tubercle behind and one on the side of each spine. Posterior margin smooth. Free tergite I –III with two tubercles. Anal operculum with two central minute tubercles, one row on posterior margin.

Venter: Coxa I with median row of four large tubercles, three apical; II with one median row of four tubercles, five apical tubercles; III with one median row of five small tubercles, four minute posterior; IV irregularly tuberculate. Posterior margin with one row of small tubercles, some scattered. Anal operculum with small scattered tubercles.

Chelicera: Segment I with three tubercles on bulla; II with three tubercles; III one large basal, two small distal. With interchelar space.

Pedipalpus: Coxa with one ventral tubercle, three dorsal tubercles (retrolateral larger). Trochanter with two ventral tubercle; one dorsal. Femur with six ventral tubercles (basal larger), slightly swollen at distal fourth. Patella swollen at distal half. Tibia ( Fig. 9View FIGURE 9 C): ectal IIiIii, mesal IIiIi, with four ventral tubercles (with long setae) next to ectal side. Tarsus ( Fig. 9View FIGURE 9 C): ectal iiIiIi, mesal iiIiIi, with seven ventral tubercles next to ectal, four next to mesal side.

Legs: Coxa I with two tubercles; II with one anterior bifid, one posterior bifid tubercle; III with one anterior tubercle fused with one of coxa IV; IV with four large tubercles close to distal margin, some sparse tubercles, one dorsoapical spine. Trochanter I with three ventral tubercles, one retrolateral; II with three ventral, two retrolateral, one dorsal large; III with three ventral, two retrolateral (apical larger); IV with one dorsoapical spine (larger), six dorsal small, six ventral, one prolateral tubercle and two retrolateral tubercles (apical larger). Femora I –II with small tubercles; III with two ventral rows of tubercles increasing in size at distal third, two dorsoapical tubercles; IV ( Fig. 9View FIGURE 9 D –E) swollen subdistad, with two ventral rows of tubercles increasing in size at apical third; two large dorsodistal spines. Patella IV ( Fig. 9View FIGURE 9 D –E) irregularly tuberculate, with one dorsodistal large tubercle, two ventroapical and one subdistal large tubercles. Tibia IV ( Fig. 9View FIGURE 9 D –E) with scattered tubercles on laterals and dorsal side, two ventral rows of tubercles (internal larger) increasing in size distad. Claws without teeth. Tarsal segmentation: 7, 16–17, 7, 7.

Penis ( Fig. 15View FIGURE 15 D –F): Ventral plate large, with apical and lateral sides concave, with four pairs of large basal setae, one pair of small intermediary setae and distal group five pairs of long (longer than distal margin) and flattened distal setae, two small setae behind distal group. Half of stylus membranous, with subapical setae.

Color: Dark-brown, margins of dorsal scutum and border of areas I –II blackish, area III almost entirely blackish. Chelicerae black reticulate. Femur and tibia IV reddish. Pedipalpus yellowish with some small black patches mainly on anterior of tibia and posterior half of tarsus.

Female description (INPA-OP 1026): Measurements: DSL 4.8; PL 1.8; DSW 3.9; PW 3.3; ID 1.8; chelicera II 2.5; III 1.4; pedipalpus 9.4; leg I 10.2; II 20.6; III 15.4; IV 19.

Anterior margin smooth. Area II with one minute tubercle each side. Free tergite I –II with two tubercles; III with 3 tubercles. Pedipalpus: coxa with two dorsal tubercles, two retrolateral. Trocanther with two ventral tubercles. Femur with three ventral (basal larger) tubercles. Tibia: ectal IIiIi, mesal IIiIi, with seven ventral tubercles. Tarsus: ectal iiIiIi, mesal IiIiIi. Femur IV with two ventroapical tubercles, one retrolateral row with larger tubercles than other of the segment. Patella-tibia IV with small tubercles. Claws with six teeth. Tarsal segmentation: 6, 15, 7, 8. Distribution: recorded only on Type locality from 2,000 to 2,400 m.a.s.l.


Instituto Nacional de Pesquisas da Amazonia