Metabiantes serratus, 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 : 44-53

publication ID	https://doi.org/10.5852/ejt.2025.1006.2989
publication LSID	lsid:zoobank.org:pub:E4FAF05B-5420-42B0-AB8D-5870FD3E370A
DOI	https://doi.org/10.5281/zenodo.16745721
persistent identifier	https://treatment.plazi.org/id/03C2879B-FFC5-FF86-442B-A32F60D1F3D7
treatment provided by	Plazi
scientific name	Metabiantes serratus
status	sp. nov.

Treatment

Metabiantes serratus sp. nov.

urn:lsid:zoobank.org:act:99512C0D-7DDB-411F-BA7F-57D07D853187

Figs 33–39 View Fig View Fig View Fig View Fig View Fig View Fig View Fig ; Table 6

Diagnosis

Metabiantes serratus sp. nov. differs from the rest of the species of Metabiantes (except M. elongatus sp. nov., M. litoralis and M. zuluanus ) by the following combination of characteristics: presence of tubercles on mesotergal areas III–V and sexually dimorphic male leg II with thickened femur, and metatarsus with tubercles on the ventral region ( Figs 33A, C View Fig , 34A, C View Fig , 38A–B View Fig , 36A–H View Fig , 39B, D, F, H View Fig ). Metabiantes serratus and M. elongatus share a remarkably similar male genital morphology, but M. serratus can be easily differentiated from M. elongatus by the presence of tubercles on free tergites I–II in contrast with granules in M. elongatus ( Fig. 34A, C View Fig vs Fig. 7C View Fig ); M. serratus also differs from M. elongatus by having a strong, thickened femur and swollen tibia and metatarsus of leg II ( Figs 36A–C, E View Fig , 39B, D, F, H View Fig vs Figs 10A, C, E View Fig , 14B, D, F, H View Fig ). Additionally, M. serratus has a pronounced constriction at the astragalus-calcaneus junction, which is absent in M. elongatus ( Figs 36E–F View Fig , 39H View Fig vs Figs 10E–F View Fig , 14H View Fig ). Males of Metabiantes serratus lack an enlarged trochanter II, distinguishing them from those of M. zuluanus ( Fig. 33A, C View Fig vs Lawrence 1937a: fig. 26). Regarding male genital morphology, M. serratus has the penis with a deeper U-shaped cleft of lamina apicalis, wider titillators, and remarkably smaller basal setae, easily differentiated from the penis of M. litoralis and M. zuluanus with shallow cleft, narrow titillators, and larger basal setae ( Fig. 37B–H View Fig vs Kauri 1961: fig. 34a–b, 22a–b).

Etymology

The species epithet ‘ serratus ’, from the Latin meaning ‘toothed like a saw’ refers to the serrated ventral transverse rows of triangular tubercles of the metatarsus II in males of this species.

Type material

Holotype

CONGO • ♂; Bas-Congo, Mayombe, Luki Forest Reserve ; 5.63333° S, 13.06667° E; 27 Sep. 2007; D. De Bakker and J.P. Michiels leg.; along trail in primary rainforest; sieving; RMCA, BE _ RMCA _ ARA. Opi. 223705. GoogleMaps

Paratypes

CONGO • 1 ♂, 3 ♀♀; same data as for holotype; RMCA, BE _ RMCA _ARA.Opi.247665 GoogleMaps • 1 ♂ (SEM voucher); same data as for holotype; MACN-Ar 45472 GoogleMaps • 2 ♂♂ (1 SEM voucher), 1 ♀ (photo voucher); same data as for holotype; MACN-Ar 45474 GoogleMaps • 6 ♂♂, 6 ♀♀; same data as for holotype; 1 Oct. 2007; RMCA, BE _ RMCA _ARA.Opi.223775 GoogleMaps

Description

Male (holotype, BE_RMCA_ARA.Opi.223705)

BODY MEASUREMENTS. Total body length 1.73, carapace length 0.61, scutum magnum length 1.56, carapace maximum width 0.97, abdominal scutum maximum width 1.27. Appendage measurements in Table 6.

DORSUM. Outline slightly hourglass-shaped with Eta (η) shape, with a very slight constriction at sulcus I level ( Figs 33A View Fig , 34A View Fig ). Carapace with scattered medial granules, wider than long, anterior border slightly convex and unarmed, with a small and rounded frontal hump ( Figs 33C View Fig , 34C View Fig ); interocular area with scattered granules ( Fig. 34A View Fig ). Cheliceral sockets not marked ( Fig. 34A View Fig ). Eyes separated near sulcus I. Carapace in lateral view straight posterior to frontal hump and becoming slightly higher toward the posterior region ( Figs 33C View Fig , 34C View Fig ). Abdominal scutum in lateral view convex ( Figs 33C View Fig , 34C View Fig ). Sulcus I deep, complete, and straight ( Fig. 34A View Fig ). Mesotergal areas granulated and well-defined; sulci II–III medially curved to the anterior body region; sulci IV–V straight ( Fig. 34A View Fig ). Mesotergal areas III–IV medially with two conical and pointed tubercles ( Figs 33A, C View Fig , 34A, C View Fig ). Mesotergal area V with two irregular rows of granules and medially with three conical tubercles ( Figs 33C View Fig , 34A, C View Fig ). Lateral borders of abdominal scutum with a row of granules ( Fig. 34A, C View Fig ). Ozopore with an oval and narrow orifice with a descending channel that extends toward the ventroposterior region ( Fig. 34C View Fig ). Free tergite I with a row of granules; free tergites I–II medially with three conical tubercles; free tergite III with a row of medial conspicuous granules ( Fig. 34A View Fig ).

VENTER. Coxa I with few small medial granules ( Fig. 34B View Fig ); coxa II incrassated, of same size as (or slightly larger than) coxa IV ( Figs 33B View Fig , 34B View Fig ); anteroposterior borders of coxa III with a row of strong granules connecting with coxae II and IV, respectively ( Figs 33B View Fig , 34B View Fig ). Posterior border of spiracular area and free sternites I–V with a row of granules ( Fig. 34B View Fig ); anal operculum granulated ( Fig. 34B–C View Fig ). Spiracles not concealed ( Fig. 34B View Fig ).

CHELICERA. Basichelicerite unarmed, with a slightly marked bulla ( Fig. 35F–G View Fig ). Cheliceral hand with sparse setae ( Fig. 35F–H View Fig ). Movable fingers with small square-shaped teeth ( Fig. 35H View Fig ).

PEDIPALP. Coxa elongated (i.e., remarkably longer than trochanter), proximally with two granules – one dorsoectally and one ventroectally ( Fig. 34A–B View Fig ). Trochanter unarmed ( Fig. 35A–B View Fig ). Femur straight, proximally with a slight ventral narrowing followed by a small ventromesal spine ( Fig. 35A–B View Fig ), ventral surface with granules and pores ( Fig. 35B, E View Fig ). Patella elongated, club-shaped, and armed with a small mesodistal spine ( Fig. 35A View Fig ). Tibia with two ventromesal and two ventroectal long spines ( Fig. 35A View Fig ). Tarsus thin, with two ventromesal and two ventroectal spines; proximal spines longer than distal spines ( Fig. 35A, C View Fig ). Setae of spines proximally smooth, then covered by scattered microtrichia ( Fig. 35C–D View Fig ).

LEGS. Femur II unarmed, thin proximally, followed by an abrupt thickness, and then tapering gradually ( Figs 33C View Fig , 36A–B View Fig , 39B, D View Fig ). Patella II long, thickened, and unarmed ( Figs 33C View Fig , 36A View Fig , 39B, D View Fig ). Tibia II distally widened, with ventral triangular-shaped tubercles that increase in size towards the distal region ( Figs 33C View Fig , 36C–D View Fig , 39B, F View Fig ). Metatarsus II with astragalus ventrally swollen and armed with equidistant transverse rows of triangular-shaped tubercles ( Figs 33C View Fig , 36E–G View Fig , 39B, H View Fig ). Limit astragalus-calcaneus defined by a strong constriction with a slightly incrassate calcaneus giving a peculiar form to distal region of the metatarsus ( Figs 33C View Fig , 36E–F View Fig , 39H View Fig ). Calcaneus ventrally mostly with ovate-shaped trichomes and some ovate-shaped base and pointed tip trichomes of variable length; lateral and dorsal surfaces of calcaneus with long thin-pointed trichomes and scattered sensilla chaetica and glandular pores ( Fig. 36F, H View Fig ). Tarsi III–IV with a dense scopula. Tarsal formula: 3(2):5(4):5:5.

COLOR (specimen preserved in 80% ethanol). Body dark brown; medial and posterior regions of carapace yellowish ( Fig. 33A View Fig ); ventral body region and appendages brown-yellowish with light brown reticulations ( Fig. 33B–C View Fig ); metatarsus II dark brown ( Figs 33C View Fig , 39B, H View Fig ).

MALE GENITALIA. Penis with distinct boundaries between pars basalis and pars distalis ( Fig. 37A View Fig ). Pars basalis tubular, slightly broadened apically, and ends in a constriction ( Fig. 37A View Fig ). Pars distalis swollen with maximum width at basal level of titillators ( Fig. 37B, D, F View Fig ). Apical edge, laminar (i.e., dorsoventrally flat), with a medial U-shaped cleft dividing into two rounded halves ( Fig. 37B, D, F, H View Fig ); halves apically less chitinous and curved ventrally ( Fig. 37C, G–H View Fig ). Pars distalis with a distal depression in the ventromedial region ( Fig. 37D, H View Fig ). Each side of pars distalis armed with short, conical microsetae, irregularly arranged, extending basally from dorsolateral to the ventrodistal region ( Fig. 37B, C, F–H View Fig ). Capsula externa with two broad titillators separated by a narrow cleft ( Fig. 37B–C, E–G View Fig ). Capsula interna is formed by two complex conductors and one stylus, basally fused. Each conductor apically with one small medial dorsal fold and one longer ventral fold, ventrally visible within the U-shaped cleft ( Fig. 37B, D, I–J View Fig ); each conductor also with one broad lateral projection, visible in the everted condition ( Fig. 37B, D–E View Fig ). Stylus with a rounded tip ( Fig. 37E View Fig ), wider basally, narrow distally, and with an irregular S-shaped curve in lateral view ( Fig. 37B–E View Fig ).

Female (paratype, MACN-Ar 45474)

BODY MEASUREMENTS. Total body length 1.83, carapace length 0.52, scutum magnum length 1.5, carapace maximum width 0.89, abdominal scutum maximum width 1.24. Appendage measurements in Table 6.

BODY. Female resembles males in the armature of the scutum magnum ( Fig. 38A–B View Fig vs Fig. 33A, C View Fig ) but differs by lacking dimorphic leg II; femur and patella not swollen as in male ( Fig. 39A, C View Fig vs Fig. 39B, D View Fig ); tibia thinner and unarmed ( Fig. 39E View Fig vs Fig. 39F View Fig ); metatarsus not swollen and unarmed ( Fig. 39G View Fig vs Fig. 39H View Fig ). Tarsal formula 3(2):4(3):5:5.

FEMALE OVIPOSITOR. Ovipositor cylindrical ( Fig. 38C View Fig ), distally bearing two lobes (furca) ( Fig. 38C–D, F View Fig ). Each furcal lobe with five long, pointed setae ( Fig. 38E View Fig ) – three dorsal and two ventral – resulting in a total of six setae on the dorsal region ( Fig. 38D View Fig ) and four on the ventral region ( Fig. 38F View Fig ). Receptacle chambers located near the base of the furcal groove ( Fig. 38D–F View Fig ).