Metabiantes kivuensis, 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 : 34-44

Metabiantes kivuensis sp. nov.

urn:lsid:zoobank.org:act:364EA7D6-9176-4A30-BE56-A53A50C64FD5

Figs 25–32 ; Table 5

Diagnosis

Major males and females (excluding minor males) of Metabiantes kivuensis sp. nov. can be distinguished from those of all other species of Metabiantes by the presence of a longitudinal division of mesotergal area IV into two halves ( Figs 25A , 31A ). Additionally, M. kivuensis differs from its congeners (except M. herculeus sp. nov., M. kaurii 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, a broad tibia, and a metatarsus ventrally with tubercles ( Figs 26A , 28A–F , 32B–C, E–F, H–I, K–L ). Males of M. kivuensis differ from those of M. herculeus by the absence of ventral tubercles on tibia II, present in the latter species ( Fig. 28C–D vs Fig. 17C–D ). The penis of M. kivuensis sp. nov. is distinctive with closely together conductors and the presence of lateral projections, unlike the widely separated conductors in M. kaurii ( Fig. 29B vs Fig. 24B ) and the absence of lateral projections in M. herculeus ( Fig. 29B vs Fig. 24B ). Furthermore, males of M. kivuensis lack an enlarged trochanter II, distinguishing them from those of M. pusulosus ( Fig. 25A, E vs Kauri 1961: fig. 5a). Also, major males of M. kivuensis are distinguished from those of M. machadoi by their abruptly thickened femur II ( Fig. 25C vs Lawrence 1957: fig. 3b). The penis of M. kivuensis features a deeper U-shaped cleft of the lamina apicalis and smaller basal setae, which distinguish it from the shallow cleft and larger basal setae in M. obscurus and M. zuurbergianus ( Fig. 29B–D vs Kauri 1961: figs 7a–b, 11a–b). Additionally, the rounded pars distalis in M. kivuensis differs from the stronger angular lateral edges of pars distalis in M. pusulosus ( Fig. 29B–D vs Kauri 1961: fig. 1a–b).

Etymology

The species epithet ‘ kivuensis ’ means ‘of or from Kivu’, a reference to the species type locality in North Kivu, a province of the Democratic Republic of the Congo.

Type material

Holotype CONGO • major ♂; Kivu-N , Kilindera , “ Face N. du Ruwenzori, camp de Kilindera” [North face of Ruwenzori, Kilindera camp]; 0.38333° N, 29.91667° E; 2950 m a.s.l.; Jul.–Aug. 1974; M. Lejeune leg.; “litière du bambusetum du Musoso” [litter of bamboo vegetation along the Musoso]; RMCA, BE _ RMCA _ ARA.Opi.154162.

Paratypes CONGO • 1 major ♂, 1 minor ♂ (photo voucher), 1 ♀ (photo voucher); same data as for holotype; RMCA, BE _ RMCA _ARA.Opi.247664 • 1 minor ♂ (SEM voucher); same data as for holotype; MACNAr 45445 • 1 major ♂; same data as for holotype; MACN-Ar 45437 .

Other material examined

CONGO • 1 major ♂, 2 ♀♀, 2 juvs; Kivu-C, Kanzuiri, “ Face N. du Ruwenzori, camp de Kanzuiri, crête du Kanzuiri” [North face of Ruwenzori, Kilindera camp, Kanzuiri Ridge]; 0.41667° N, 29.9° E; 3500 m a.s.l.; Jul.–Aug. 1974; M. Lejeune leg.; “dans mousses” [in mosses]; RMCA, BE _ RMCA _ARA. Opi.154244 • 1 minor ♂, 1 ♀; same data as for preceding; MACN-Ar 45470 .

Description

Male (holotype, BE_RMCA_ARA.Opi.154162)

BODY MEASUREMENTS. Total body length 2.95, carapace length 0.94, scutum magnum length 2.58, carapace maximum width 1.43, abdominal scutum maximum width 2.09. Appendage measurements in Table 5.

DORSUM. Outline slightly hourglass-shaped with Eta (η) shape, with a very slight constriction at sulcus I level ( Figs 25A , 26A ). Carapace wider than long with a row of granules on the posterior margin and granules concentrated laterally around eyes, anterior border slightly convex and unarmed ( Fig. 26A ); Cheliceral sockets not marked ( Fig. 26A ). Eyes separated near sulcus I; interocular area smooth ( Figs 25A , 26A ). Carapace in lateral view straight at anterior region and slightly higher posteriorly ( Figs 25C , 26C ). Abdominal scutum in lateral view convex ( Figs 25C , 26C ). Sulcus I deep, complete, and slightly curved to the anterior body region ( Figs 25A , 26A ). Mesotergal areas granulated and well-defined, with sulci II–V marked but shallower than sulcus I; sulci II–III medially arched to the anterior body region; sulcus IV medially arched to posterior body region ( Fig. 25A ); sulcus V medially invaginated towards mesotergal area IV dividing it into two ( Fig. 25A ). Mesotergal area V with two rows of granules ( Fig. 26A ). Lateral borders of abdominal scutum with two rows of granules ( Fig. 26A ). Ozopore with an oval and narrow orifice with a descending channel that extends toward the ventroposterior region ( Fig. 26C ). Free tergites granulated ( Fig. 26A, C ).

VENTER. Coxa I with few small medial setiferous granules ( Fig. 26B ); coxa II incrassated, slightly bigger than coxa IV ( Fig. 25B ); anteroposterior borders of coxa III with a row of strong granules connecting with coxae II and IV, respectively ( Fig. 26B ). Lateroposterior border of spiracular area and lateral border of free sternites I–V with rows of granules ( Fig. 26B–C ); anal operculum granulated ( Fig. 26B–C ). Spiracles not concealed ( Fig. 26B ).

CHELICERA. Basichelicerite unarmed with a slightly marked bulla ( Figs 26C , 27F–G ). Cheliceral hand with sparse setae ( Fig. 27F–H ). Movable fingers with small, square-shaped teeth ( Fig. 27H ).

PEDIPALP. Coxa elongated (i.e., remarkably longer than trochanter), proximally with one dorsoectal granule and three ventroectal granules – one proximal and two distal ones ( Figs 25A , 26A–B ). Trochanter unarmed ( Fig. 27A ). Femur robust, thick, and straight, ventroproximally with one mesal spine ( Fig. 27A ); ventral surface with small granules and scattered pores ( Fig. 27B–C ). Patella elongated, club-shaped, with a small mesodistal spine ( Fig. 27A ). Tibia with two ventroectal and two ventromesal spines ( Fig. 27A ). Tarsus inflated, spheroid in shape, with two ventromesal and two ventroectal spines; proximal spines longer than distal ones ( Fig. 27A, D ); ventral surface with conspicuous tubercles containing aggregate pores ( Fig. 27D–E ).

LEGS. Coxa II with a row of dorsal granules ( Fig. 26C ). Femur II proximally thin, followed by an abrupt strong thickness, then tapering gradually ( Figs 25C , 32C, F ). Patella II short and thickened ( Figs 25C , 32C, F ). Tibia II dorsally widened ( Figs 25C , 32C, I ) and unarmed ( Figs 28C–D , 32C, I ). Metatarsus II with elongated astragalus, ventrally slightly swollen and armed with small triangular-shaped tubercles ( Fig. 28A, E ). Calcaneus occupies less than the last third of metatarsus, with trichomes and scattered long sensilla chaetica distributed along all surfaces; trichomes with wider ovate-shaped bases, pointed tips, and variable length ( Fig. 28E–F ). Tarsi III–IV with a dense scopula. Tarsal formula: 3(2):5(4):5:5.

COLOR (specimen preserved in 80% ethanol). Body yellowish; carapace with light brown reticulations on the anterior and lateral sides ( Fig. 25A, C ). Anterior, lateral, and lateroposterior borders of mesotergal area I dark brown ( Fig. 25A ). Lateroanterior, lateral, and posterior borders of mesotergal area II dark brown ( Fig. 25A ). Lateroposterior border of mesotergal areas III–IV with dark brown patches. Mesotergal areas II–III medially with four medial dark points – two anterior and two posterior ones. Mesotergal area IV with two medial dark points in each half ( Fig. 25A ). Posterior border and free tergites with a row of dark points ( Fig. 25A ). Free sternite V and anal operculum with dark brown patches ( Fig. 25B ). Appendages with light brown reticulations ( Figs 25A–C , 32C, F, I, L ).

MALE GENITALIA. Penis with distinguishable limits between pars basalis and pars distalis ( Fig. 29A ). Pars basalis tubular, thin at the base, slightly broadened apically, and ending in a slight constriction ( Fig. 29A ). Pars distalis swollen, with maximum width at titillator level ( Figs 29B, D , 30A ). Apical edge, laminar (i.e., dorsoventrally flat) with a large, open U-shaped cleft medially dividing into two rounded halves ( Figs 29B, D , 30A, C ); halves apically curved ventrally, less chitinous, and potentially inflatable by hemolymph pressure ( Fig. 30C ). Pars distalis with a small apical depression in the ventromedial region ( Figs 29D , 30C ). Each side of pars distalis armed with irregularly arranged microsetae, extending from dorsolateral to the ventrodistal region ( Figs 29B–D , 30A–C ). Capsula externa with two broad titillators ending in rounded tips, separated by a close U-shaped cleft; tips with inner rounded projections ( Fig. 30E–F ). Capsula interna formed by two complex conductors, each one with one laminar medial small dorsal fold and one longer ventral fold, with a lateral extension covering partially the dorsal fold, visible within the U-shaped cleft ( Figs 29B , 30A, D–F ); each conductor also with one broad lateral projection ( Fig. 29B ); stylus long and tubular, with its tip covered by conductors ( Fig. 29B–D ).

Minor male (paratype, BE_RMCA_ARA.Opi.247664)

BODY MEASUREMENTS. Total body length 2.74, carapace length 0.96, scutum magnum length 2.5, carapace maximum width 1.4, abdominal scutum maximum width 1.98. Appendage measurements in Table 5.

BODY. Minor male resembles major male in the armature of the scutum magnum, except for mesotergal area IV, which is not divided ( Figs 26A , 31G vs Fig. 25A ). Minor male has a dimorphic leg II but differs from major male by having remarkably thinner femur, patella, and tibia ( Figs 31H , 32B, E, H vs Figs 25C , 32C, F, I ); metatarsus II slightly thinner than that of major males ( Fig. 32K vs Fig. 32L ). Tarsal formula: 3(2):5(3):5:5.

Female (paratype, BE_RMCA_ARA.Opi.247664)

BODY MEASUREMENTS. Total body length 2.91, carapace length 0.89, scutum magnum length 2.56, carapace maximum width 1.4, abdominal scutum maximum width 2.2. Appendage measurements in Table 5. BODY. Female resembles both minor and major males in the armature of the scutum magnum ( Fig. 31A– B vs Figs 25A, C , 31G–H ). Female differs from the minor male, but not from the major male, by having the mesotergal area IV divided ( Fig. 31A vs Figs 26A , 31G ). Female differs from both major and minor males by having a thin pedipalp tarsus and lacking a dimorphic leg II ( Fig. 31B vs Figs 25C , 31H ), with femur and patella thinner than in minor and major males ( Fig. 32D vs Fig. 32E–F ); tibia with similar width to that of the minor male and thinner than in the major male ( Fig. 32G vs Fig. 32H–I ); metatarsus II slightly thinner than that of minor and major males ( Fig. 32J vs Fig. 32K–L ). Tarsal formula 3(2):5(4):5:5.

FEMALE GENITALIA. Ovipositor cylindrical ( Fig. 31C ), distally bearing two lobes (furca) ( Fig. 31C–D, F ). Each furcal lobe with five long, pointed setae ( Fig. 31E ) – three dorsal and two ventral ones – resulting in a total of six setae on the dorsal region ( Fig. 31D ) and four on the ventral region ( Fig. 31F ). External surface of furcal lobes with several short, pointed lateral projections, irregularly distributed ( Fig. 31E ). Receptacle chambers located near the base of the furcal groove ( Fig. 31D–F ).

Distribution

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

Figures

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. 26. Metabiantes kivuensis sp. nov., paratype, minor ♂ (MACN-Ar 45445), scanning electron micrographs of habitus. A. Dorsal view. B. Ventral view. C. Lateral view. Scale bars = 300 µm.

Fig. 27. Metabiantes kivuensis sp. nov., paratype, minor ♂ (MACN-Ar 45445), scanning electron micrographs of pedipalp and chelicera. A–E. Right pedipalp. A. Mesal view. B. Detail of femur. C. Detail of femoral granules. D. Tibia and tarsus, ventroectal view. E. Detail of aggregate pores of tarsus. F–H. Left chelicera. F. Mesal view. G. Ectal view. H. Frontal view. Scale bars: A = 200 µm; B = 20 µm; C, E = 10 µm; D, F–H = 100 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. 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. 30. Metabiantes kivuensis sp. nov., paratype, minor ♂ (MACN-Ar 45445), scanning electron micrographs of penis. A. Dorsal view. B. Lateral view. C. Ventral view. D. Detail of conductors, dorsal view. E. Anterior view. F. Detail of conductors, anterior view. Conductors in red, titillators in magenta, microsetae in yellow. Abbreviations: DF = dorsal fold; VF = ventral fold. Scale bars: A–C = 40 µm; D, F = 10 µm; E = 20 µm.

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. 32. Metabiantes kivuensis sp. nov., sexual dimorphism, left legs II photos. A, D, G, J. Paratype, ♀ (BE_RMCA_ARA.Opi.247664). B, E, H, K. Paratype, minor ♂ (BE_RMCA_ARA.Opi.247664). C, F, I, L. Holotype, major ♂ (BE_RMCA_ARA.Opi.154162). A–C. Leg II, retrolateral view. D–F. Femur and patella, retrolateral view. G–I. Tibia, retrolateral view. J–L. Metatarsus and tarsus, retrolateral view. Scale bars = 500 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. 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. 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.