Metabiantes herculeus, Mamani & Jocqué & Pérez-González, 2025

Mamani, Vanesa, Jocqué, Merlijn & Pérez-González, Abel, 2025, Notes on African Biantinae with sexual dimorphism in leg II: five new Metabiantes species and redescription of Clinobiantes paradoxus (Opiliones: Laniatores: Biantidae), European Journal of Taxonomy 1006, pp. 1-58 : 21-28

Metabiantes herculeus sp. nov.

urn:lsid:zoobank.org:act:D394CC39-C444-49BC-8707-824153F3ED9A

Figs 15–20 ; Table 3

Diagnosis

Metabiantes herculeus sp. nov. differs from its congeners (except M. kaurii sp. nov., M. kivuensis sp. nov., M. machadoi , M. obscurus , M. pusulosus , and M. zuurbergianus ) by the following combination of traits: absence of tubercles on mesotergal areas III–V and free tergites; sexually dimorphic male leg II with a thickened femur and patella, a broad tibia, and a metatarsus ventrally armed with tubercles ( Figs 17A–F , 20B, D, F, H ). Males of M. herculeus differ from those of M. kaurii and M. kivuensis by having ventral tubercles on tibia II, absent in the latter species ( Fig. 17C–D vs Figs 23C–D , 28C–D ). The penis of M. herculeus is distinctive with conductors closely together and lacking lateral projections, unlike the widely separated conductors in M. kaurii ( Fig. 18B vs Fig. 24B ) and the presence of lateral projections in M. kivuensis ( Fig. 18B vs Fig. 29B ). Additionally, the shorter, non-contacting halves of the lamina apicalis in M. herculeus contrast with the longer, contacting halves in M. kaurii ( Fig. 18B, D vs Fig. 24B, D ). Unlike M. kivuensis , M. herculeus lacks a longitudinal division of mesotergal area IV into two halves, which is characteristic of females and major males of M. kivuensis ( Figs 15A , 16A , 19A vs Figs 25A , 31A ). Furthermore, males of M. herculeus lack an enlarged trochanter II, distinguishing them from M. pusulosus ( Fig. 15A vs Kauri 1961: fig. 5a). Also, males of M. herculeus are easily distinguished from those of M. machadoi by their abruptly thickened femur II ( Fig. 17A–B vs Lawrence 1957: fig. 3b) and from those of M. zuurbergianus by the presence of ventral tubercles on tibia II ( Fig. 17C–D vs Kauri 1961: 25). The penis of M. herculeus features a deeper U-shaped cleft of the lamina apicalis, wider titillators, and smaller basal setae, which distinguish it from the shallow cleft, narrow titillators, and larger basal setae in M. obscurus and M. zuurbergianus ( Fig. 18B–D vs Kauri 1961: figs 7a–b, 11a–b). Additionally, the rounded pars distalis with wide titillators in M. herculeus differs from the triangular lateral edges of pars distalis and narrow titillators in M. pusulosus ( Fig. 18B–D vs Kauri 1961: fig. 1a–b).

Etymology

The species name is derived from the Latin word Hercules , the Roman counterpart of the Greek hero Heracles , the most popular figure in ancient Greek mythology. It can be understood as something related to or characteristic of Hercules , often indicating strength and power qualities, specifically referring to the strongly thickened femur II of the species.

Type material

Holotype TANZANIA • ♂; Mbeya Region, Tukuyu, Ushirika area, Kayuki tea estate ; 9.41667° S, 34.66667° E; 1200 m a.s.l.; 29 Nov. 1991; R. Jocqué leg.; litter; RMCA, BE _ RMCA _ARA.Opi.173473.

Paratype TANZANIA • 1 ♀; same data as for holotype; RMCA, BE _ RMCA _ ARA.Opi.247663 .

Description

Male (holotype, BE_RMCA_ARA.Opi.173473)

BODY MEASUREMENTS. Total body length 2.52, carapace length 0.86, scutum magnum length 2.07, carapace maximum width 1.43, abdominal scutum maximum width 1.68. Appendage measurements in Table 3.

DORSUM. Outline slightly hourglass-shaped with Eta (η) shape, with a very slight constriction located at sulcus I level ( Figs 15A , 16A ); carapace with scattered granules, wider than long, with a small and rounded frontal hump ( Figs 15A , 16A ); anterior border slightly convex and unarmed ( Figs 15A , 16A ). Cheliceral sockets not marked ( Fig. 16A ). Eyes separated near sulcus I; interocular area finely granulated ( Figs 15A, E , 16A ). Carapace in lateral view straight posterior to frontal hump and becoming slightly higher toward the posterior region ( Fig. 15E ). Abdominal scutum in lateral view convex ( Fig. 15E ).

Sulcus I deep and complete ( Fig. 16A ). Mesotergal areas granulated and well-defined, with sulci II–V marked but shallower than sulcus I; medially sulci II–III slightly curved to anterior body region; sulci IV–V straight ( Fig. 16A ). Mesotergal area V granulated ( Fig. 16A ). Lateral margins of abdominal scutum with two rows of granules ( Fig. 16A ). Free tergites granulated ( Figs 15E , 16A ).

VENTER. Coxa I with few small setiferous granules ( Fig. 15C ); coxa II incrassated, bigger than coxa IV ( Fig. 15B–D ); anteroposterior borders of coxa III with a row of strong granules connecting with coxae II and IV, respectively ( Fig. 15C–D ). Posterior border of spiracular area, free sternites I–V with a row of granules; anal operculum granulated ( Fig. 15D–F ). Spiracles not concealed ( Fig. 15D ).

CHELICERA. Basichelicerite unarmed, with not marked bulla ( Fig. 16G ). Cheliceral hand with sparse setae ( Fig. 16G–H ). Fixed and movable fingers with small triangular-shaped teeth.

PEDIPALP. Coxa elongated (i.e., remarkably longer than trochanter), dorsoproximally with one mesal and one ectal granule ( Figs 15A , 16A ). Trochanter smooth ( Fig. 16B–C ). Femur straight, proximally with one small ventromesal spine, ventral surface with granules ( Fig. 16B–F ). Patella elongated, club-shaped, with a small mesodistal spine ( Fig. 16B–C ). Tibia with two ventroectal and two ventromesal spines; distal ventroectal spine with the highest socket and longest seta ( Fig. 16B–C ). Tarsus inflated, with oval shape, armed with two ventromesal and two ventroectal spines, proximal spines longer than distal spines ( Figs 15E , 16B–C ); tarsus ventrally with granules on the medial surface ( Fig. 16C ).

LEGS. Femur II proximally thin, followed by an abrupt strong thickness, then tapering gradually ( Figs 15E , 17A–B , 20B, D ). Patella II long, thickened ( Figs 17A , 20B ). Tibia II widened with ventral small triangular-shaped tubercles ( Figs 17C–D , 20F ). Metatarsus II with a very long calcaneus that occupies more than half of the ventral metatarsus ( Fig. 17E ); astragalus short, with equidistant transverse rows of tubercles ( Fig. 17E ); calcaneus with scattered low and rounded trichomes, long sensilla chaetica and glandular pores on the ventral surface ( Fig. 17E–F ). Tarsi III–IV with a dense scopula. Tarsal formula: 3(2):5(4):5:5.

COLOR (specimen preserved in 80% ethanol). Body brown-yellowish ( Fig. 15A, C–E ); carapace, coxae I–IV, and appendages with brown reticulations ( Figs 15A–E ); lateroanterior, lateral, and lateroposterior borders of mesotergal areas dark brown; mesotergal areas I–III with two medial dark brown patches, closer in mesotergal area III; mesotergal area IV with one posterior medial dark brown patch; mesotergal area V with two lateral dark brown patches; free tergites I–II with two lateral dark brown patches and one medial rounded spot; free tergite III dark brown ( Fig. 15A, E ); posterior border of spiracular area and free sternites I–IV with a line of dark brown patches ( Fig. 15B–F ); anal operculum dark brown ( Fig. 15F ).

MALE GENITALIA. Penis with clearly defined boundaries between pars basalis and pars distalis ( Fig. 18A ). Pars basalis basally thin, broadens medially, with distal constriction ( Fig. 18A ). Pars distalis slightly swollen with maximum width at titillator level ( Fig. 18B ). Apical edge laminar (i.e., dorsoventrally flat) with a medial U-shaped cleft that divides it into two rounded and elongated halves ( Fig. 18B, D ); these halves are apically less chitinous and could possibly be inflated by hemolymph pressure ( Fig. 18D ). Pars distalis with a distal depression in the ventromedial region ( Fig. 18D ). Each side of pars distalis armed with short, conical microsetae irregularly arranged, extending basally from the dorsolateral to the ventroapical side ( Fig. 18B–D ). Capsula externa with two broad titillators separated by a dorsal cleft basally narrow ( Fig. 18B ). Capsula interna formed by two conductors and one stylus, basally fused. Each one with two laminar folds apically, one small pointed dorsal fold and one longer ventral fold, ventrally visible within the U-shaped cleft; stylus tubular, and irregular S-shaped in lateral view with its free tip fully covered by conductors ( Fig. 18B–D ).

Female (paratype, BE_RMCA_ARA.Opi.247663)

BODY MEASUREMENTS. Total body length 2.16, carapace length 0.67, scutum magnum length 1.83, carapace maximum width 1.12, abdominal scutum maximum width 1.64. Appendage measurements in Table 3.

BODY. Female resembles male in the armature of the scutum magnum ( Fig. 19A–B vs Fig. 15A, E ) but differs from male by having a thinner pedipalp tarsus ( Fig. 19B vs Fig. 15E ). Also, female differs by having a thin leg II ( Fig. 20A vs Fig. 20B ); femur and patella II thin ( Fig. 20A, C vs Fig. 20B, D ); tibia II thin and unarmed ( Fig. 20E vs Fig. 20F ); metatarsus II and basitarsus thin and unarmed, with pseudoarticular rings ( Fig. 20A, G vs Fig. 20B, H ). Tarsal formula 3(2):5(4):5:5.

FEMALE GENITALIA. Ovipositor cylindrical ( Fig. 19C ), distally bearing two long lobes (furca) ( Fig. 19C– D, F ). Each furcal lobe with five long, pointed setae ( Fig. 19E ) – three dorsally and two ventrally – resulting in a total of six setae on the dorsal region ( Fig. 19D ) and four on the ventral region ( Fig. 19F ). Receptacle chambers located near the base of the furcal groove ( Fig. 19D, F ).

Distribution

Known only from the type locality ( Fig. 40 ).

Figures

Fig. 15. Metabiantes herculeus sp. nov., holotype, ♂ (BE_RMCA_ARA.Opi.173473), habitus photos. A. Dorsal view. B. Ventral view. C. Ventral view with detail of coxae I–IV. D. Ventral view with detail of coxa IV and free sternites. E. Lateral view. F. Posterior view. Scale bars: A–B, E = 1 mm; C = 200 µm; D, F = 500 µm.

Fig. 16. Metabiantes herculeus sp. nov., holotype, ♂ (BE_RMCA_ARA.Opi.173473). A–C, F–H. Drawings of habitus, pedipalp, and chelicera. D–E. Photos of pedipalp femur. A. Habitus, dorsal view. B–F. Left pedipalp. B. Ectal view. C. Mesal view. D. Femur, mesal view. E. Detail of femur surface. F. Femur, ventral view. G–H. Left chelicera. G. Ectal view. H. Frontal view. White triangle indicates a granule. Scale bars: A–C, F–H = 500 µm; D = 250 µm; E = 200 µm.

Fig. 17. Metabiantes herculeus sp. nov., holotype, ♂ (BE_RMCA_ARA.Opi.173473), scanning electron micrographs of right leg II. A. Leg II, retrolateral view. B. Femur, prolateral view. C. Tibia, prolateral view. D. Detail of tibia surface. E. Metatarsus, ventroprolateral view. F. Detail of astragalus and calcaneus surfaces. Black triangle indicates a trichome; white triangle indicates a sensillum chaeticum; black arrow indicates a glandular opening. Scale bars: A = 300 µm; B = 200 µm; C, E = 100 µm; D = 40 µm; F = 10 µm.

Fig. 18. Metabiantes herculeus sp. nov., holotype, ♂ (BE_RMCA_ARA.Opi.173473), penis drawings. A–B. Dorsal view (detail of conductors within box). C. Lateral view. D. Ventral view. Stylus in green, conductors in brownish red, titillators in magenta. Abbreviations: Co = conductor; DF = dorsal fold; PB = pars basalis; PD = pars distalis; Ti = titillator; VF = ventral fold. Scale bars: A = 500 µm; B–D = 100 µm.

Fig. 19. Metabiantes herculeus sp. nov., paratype, ♀ (BE_RMCA_ARA.Opi.247663). A–B. Habitus photos. A. Dorsal view. B. Lateral view. C–F. Ovipositor drawings. C–D. Dorsal view. E. Lateral view. F. Ventral view. Abbreviations: FG = furcal groove; Fu = furca; L = lobe; S = seta; SrA = seminal receptacle area; Tr = truncus. Scale bars: A, C = 500 µm; B = 1 mm; D–F = 100 µm.

Fig. 20. Metabiantes herculeus sp. nov., sexual dimorphism, left legs II photos. A, C, E, G. Paratype, ♀ (BE_RMCA_ARA.Opi.247663). B, D, F, H. Holotype, ♂ (BE_RMCA_ARA.Opi.173473). A–B. Leg II, retrolateral view. C–D. Femur, retrolateral view. E–F. Tibia, retrolateral view. G–H. Metatarsus, retrolateral view. Arrow indicates a pseudoarticular ring. Scale bars: A–B = 1 mm; C–H = 500 µm.

Fig. 23. Metabiantes kaurii sp. nov., holotype, ♂ (MACN-Ar 46476), photographs and scanning electron micrographs of left leg II. A. Femur, retrolateral view. B. Femur, ventral view. C–D. Tibia, retrolateral view. E–F. Metatarsus, retrolateral view. G. Metatarsus, ventral view. H. Detail of astragalus and calcaneus, retrolateral view. I. Detail of astragalus and calcaneus surface, ventral view. J. Detail of calcaneus surface, retrolateral view. Black triangle indicates a trichome; white triangle indicates a sensillum chaeticum.Abbreviations: As = astragalus; Ca = calcaneus. Scale bars: A, C, E = 500 µm; B, F = 200 µm; D, G = 100 µm; H = 40 µm; I = 30 µm; J = 5 µm.

Fig. 28. Metabiantes kivuensis sp. nov., paratype, minor ♂ (MACN-Ar 45445), scanning electron micrographs of left leg II. A. Leg II, prolateral view. B. Femur, prolateral view. C. Tibia, prolateral view. D. Detail of tibia surface. E. Detail of astragalus and calcaneus, prolateral view. F. Detail of calcaneus surface. Black triangle indicates a trichome; white triangle indicates a sensillum chaeticum. Scale bars: A = 400 µm; B = 200 µm; C = 100 µm; D = 20 µm; E = 40 µm; F = 10 µm.

Fig. 24. Metabiantes kaurii sp. nov., holotype, ♂ (MACN-Ar 46476), penis drawings. A–B. Dorsal view (detail of conductors within box). C. Lateral view. D. Ventral view. Stylus in green, conductors in brownish red, titillators in magenta. Abbreviations: Co = conductor; PB = pars basalis; PD = pars distalis; St = stylus; Ti = titillator. Scale bars: A = 500 µm; B–D = 100 µm.

Fig. 29. Metabiantes kivuensis sp. nov., holotype, major ♂ (BE_RMCA_ARA.Opi. 154162), penis drawings. A–B. Dorsal view (detail of conductors within box). C. Lateral view. D. Ventral view. Stylus in green, conductors in brownish red, titillators in magenta. Abbreviations: Co = conductor; DF = dorsal fold; LP = lateral projection; PB = pars basalis; PD = pars distalis; Ti = titillator; VF = ventral fold. Scale bars: A = 500 µm; B–D = 100 µm.

Fig. 25. Metabiantes kivuensis sp. nov., holotype, major ♂ (BE_RMCA_ARA.Opi. 154162), habitus photos. A. Dorsal view. B. Ventral view. C. Lateral view. Scale bars = 1 mm.

Fig. 31. Metabiantes kivuensis sp. nov., sexual dimorphism. A–F. Paratype, ♀ (BE_RMCA_ARA. Opi.247664). A–B. Habitus photos. A. Dorsal view. B. Lateral view. C–F. Ovipositor drawings. C–D. Dorsal view. E. Lateral view. F. Ventral view. G–H. Paratype, minor ♂ (BE_RMCA_ARA. Opi.247664), photo habitus. G. Dorsal view. H. Lateral view. Abbreviations: FG = furcal groove; Fu = furca; L = lobe; P = projection; S = seta; SrA = seminal receptacle area; Tr= truncus. Scale bars: A–B, G–H = 1 mm; C–F = 100 µm.

Fig. 40. Geographical distribution of Clinobiantes paradoxus Roewer, 1927 and the new species of Metabiantes Roewer, 1915 herein described. Clinobiantes paradoxus (red hexagon) in Cameroon; M. kivuensis sp. nov. (green triangle), M. serratus sp. nov. (magenta circle), and M. elongatus sp. nov. (yellow inverted triangle) in Democratic Republic of Congo; M. herculeus sp. nov. (pink square) in Tanzania; M. kaurii sp. nov. (orange star) in Mozambique.