Metabiantes serratus sp. nov.

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

Figs 33–39; 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, 34A, C, 38A–B, 36A–H, 39B, D, F, H). 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 vs Fig. 7C); 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, 39B, D, F, H vs Figs 10A, C, E, 14B, D, F, H). Additionally, M. serratus has a pronounced constriction at the astragalus-calcaneus junction, which is absent in M. elongatus (Figs 36E–F, 39H vs Figs 10E–F, 14H). Males of Metabiantes serratus lack an enlarged trochanter II, distinguishing them from those of M. zuluanus (Fig. 33A, C 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 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.

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

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

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

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

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

LEGS. Femur II unarmed, thin proximally, followed by an abrupt thickness, and then tapering gradually (Figs 33C, 36A–B, 39B, D). Patella II long, thickened, and unarmed (Figs 33C, 36A, 39B, D). Tibia II distally widened, with ventral triangular-shaped tubercles that increase in size towards the distal region (Figs 33C, 36C–D, 39B, F). Metatarsus II with astragalus ventrally swollen and armed with equidistant transverse rows of triangular-shaped tubercles (Figs 33C, 36E–G, 39B, H). 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, 36E–F, 39H). 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). 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); ventral body region and appendages brown-yellowish with light brown reticulations (Fig. 33B–C); metatarsus II dark brown (Figs 33C, 39B, H).

MALE GENITALIA. Penis with distinct boundaries between pars basalis and pars distalis (Fig. 37A). Pars basalis tubular, slightly broadened apically, and ends in a constriction (Fig. 37A). Pars distalis swollen with maximum width at basal level of titillators (Fig. 37B, D, F). Apical edge, laminar (i.e., dorsoventrally flat), with a medial U-shaped cleft dividing into two rounded halves (Fig. 37B, D, F, H); halves apically less chitinous and curved ventrally (Fig. 37C, G–H). Pars distalis with a distal depression in the ventromedial region (Fig. 37D, H). 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). Capsula externa with two broad titillators separated by a narrow cleft (Fig. 37B–C, E–G). 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); each conductor also with one broad lateral projection, visible in the everted condition (Fig. 37B, D–E). Stylus with a rounded tip (Fig. 37E), wider basally, narrow distally, and with an irregular S-shaped curve in lateral view (Fig. 37B–E).

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 vs Fig. 33A, C) but differs by lacking dimorphic leg II; femur and patella not swollen as in male (Fig. 39A, C vs Fig. 39B, D); tibia thinner and unarmed (Fig. 39E vs Fig. 39F); metatarsus not swollen and unarmed (Fig. 39G vs Fig. 39H). Tarsal formula 3(2):4(3):5:5.

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

Distribution

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