Rowellacris obscuripes ( Miller, 1929 ), 2025

Hemp, Claudia, Ritchie, J. Mark, Cigliano, Maria Marta, Heller, Klaus-Gerhard, Warchalowska-Śliwa, Elżbieta, Grzywacz, Beata, Linde, Jackson, Uluar, Onur, Ngoute, Charly Oumarou & Song, Hojun, 2025, Out of sight, out of mind? Ixalidiidae, a new family of African forest grasshoppers (Orthoptera, Acridoidea) revealed by molecular phylogenetics and genital morphology, Zoosystema 47 (24), pp. 489-553 : 523-525

Rowellacris obscuripes ( Miller, 1929) nom. rev., n. comb.

( Figs 1; 2E; 5F; 15; Tables 9 ; 11 )

Ixalidium obscuripes Miller, 1929: 80 .

Ixalidium haematoscelis – Dirsh 1966: 103 (incorrectly synonymised; here recalled from synonymy).

TYPE MATERIAL EXAMINED. — Holotype. Tanzania • ♂; Tanga District, Msimbazi River; 5.XII.1926; N. C. E. Miller leg.; NHMUK.

OTHER MATERIAL EXAMINED. — Tanzania • 1 ♂; Tanga; A. Karasek leg.; paratype of Ixalidium usambaricum ; MfN URI: http://coll. mfn-berlin.de/u/44d6c4; DORSA BA000802S05 ; MfN • 1 ♂; [ Tanga Region, Muheza District], [Mlinga Mountain], Magrotto [=Magoroto Forest Estate]] ; 05°07’0”S, 38°45’0”E; [ 700-1069 m a.s.l.]; 27.VII.1994; A. Hochkirch leg.; on forest path; DNA voucher E2, extracted 19.X.2022, Box SA00924142, Tube: FD18757436; NHMUK 015134130 ; Coll. AH • 1 ♂; Tanga Region, nr Tanga, Amboni Caves ; 05°03’60”S, 39°2’60”E; 27.I.1998.; ground litter under tree; Coll. AH • 2♂, 1♀; Manza Bay, Kwale Island ; 4°57’30”S, 39°10’17”E; 1-2 m a.s.l.; IV. 2021; C. Hemp leg.; coastal forest leaf litter; Coll. CH • 1 ♀; Manza Bay, Kwale Island, Sacred Forest ; 4°57’43”S, 39°8’28”E; 12 m a.s.l.; X.2021; C. Hemp leg.; Coll. CH . Kenya • 10 ♂, 21 ♀; Shimba Hills ; III.1941; V. G. L. Van Someren leg.; NHMUK • 4 ♀; Shimba Hills ; VII.1939; V. G. L. Van Someren leg.; NHMUK • 1 ♂, 1 ♀, 1 nymph; Shimba Hills , W side, scarp road, 4°15’26”S, 39°23’16”E; 19.IX.1982; N. D. Jago leg.; forest; NHMUK • 1 ♂; Tiwi ; III.1941; V. G. L. Van Someren leg.; NHMUK • 1 ♂, 1 ♀; Diani Beach, 22 miles S of Mombasa ; 27.III.1953; E. S. Brown leg.; NHMUK • 1 ♂; Diani Beach, 22 miles S of Mombasa ; 30.III.1953; E. S. Brown leg.; Julbernardia / Manilkara forest; NHMUK • 3 ♂, 7 ♀, 2 nymphs; Mangea Hill, nr summit ; 03°16’S, 39°43’E; 1500 feet a.s.l.; 1.III.1988; N. D. Jago, J. P. Grunshaw, I. A. D. Robertson leg.; NHMUK • 4 ♂, 2 ♀; Kwale District, Mrima Hill, S of Kikoneni , forest; 4°29’9”S, 39°16’10”E; 800 feet a.s.l.; 21.IX.1982; N. D. Jago leg.; NHMUK • 11 ♂, 12 ♀, 4 nymphs; Kwale District, Mrima Hill, SW side, upper slope , forest; 4°29’9”S, 39°16’10”E; 500-800 feet a.s.l.; 29.1.1990; J. M. Ritchie, M. N. Mungai, J. Muli leg.; NHMUK • 2 ♂, 2 ♀; North Diani Beach, 20 miles S of Mombasa, 1 km N of Tradewinds Hotel ; 16.IV.1975; 100 metres wide foreshore and exploited coastal thicket, 100-500 metres from beach; 4°18’S, 39°35’E; c. 20 ft a.s.l.; I. A. D. & A. Robertson leg.; NHMUK • 5 ♂, 6 ♀; W of Gazi, Mombasa to Ramisi road, Gogoni Forest ; 21.IX.1982; N. D. Jago leg.; NHMUK • 1 ♂, 3♀, 3 nymphs; Kwale District, Kilibasi Hill, SW side, upper and lower slopes ; 3°57’S, 38°57’E; 1400-2700 ft a.s.l.; 27.I.1990; J. M. Ritchie & M. N. Mungai leg.; forest and mist forest; NHMUK • 8♂, 13 ♀, 1 nymph; Dzombo [Jombo] Hill , upper slope, N side; 4°26’S, 39°13’E; 1000-1300 feet a.s.l.; 30.I.1990; J. M. Ritchie & M. N. Mungai leg.; forest; NHMUK • 1 ♂; Kwale District, 20 kms N of Lunga Lunga ; 4°33’S, 39°08’E; 31.I. 1990, J. M. Ritchie & M. N. Mungai leg.; lowland dry forest; NHMUK • 1 ♀; Cha Simba Limestone outcrop ; 03°44’S, 39°42’E; 650 feet a.s.l.; 29.II.1988; N. D. Jago, J. P. Grunshaw, I. A. D. Robertson leg.; Gymnocarpus / Pandanus ( Ficus) / Euphorbia forest; NHMUK • 4 ♀; plain between Linango and Kwale, Route C106, Godoni Forest ; 4°09’S, 39°26’E; 18.IX.1982; N. D. Jago leg.; NHMUK • 2♀; 3.5 kms NW of Jaribuni ; 3°38’S, 39°44’E; N. D. Jago leg.; savanna woodland with cycads and aloes; NHMUK .

DIAGNOSIS. — Subgenital plate shorter than other species of Rowellacris Ritchie & Hemp n. gen. ( Fig. 5F). Posterior margin of basal section of supra-anal plate strongly concave, with flanges at outer edges ( Figs 5F; 15A). Cingulum hind margin strongly convex, largely or completely covering sub-dorsal lobe ( Fig. 15B). Sub-dorsal lobe strongly bilobate posteriorly ( Fig. 15E).

Measurements: Table 11.

DISTRIBUTION

Originally described by Miller (1929) from the riverine forest bordering the lower Msimbazi River which flows through the centre of Dar Es Salaam, the type locality of R. obscuripes n. comb. has not yielded any further specimens since then. The type locality is now severely affected by urban encroachment entailing habitat destruction, waste dumping and pollution as well as bi-annual flooding worsened by upstream deforestation in the Pugu Hills and land-use change ( World Bank 2022). Morphologically similar specimens are known from patches of woodland, dry forest and thicket at Magoroto, Amboni, Tanga ( paratype of R. usambaricum n. comb.), from coastal scrub forest on coral on Kwale Island (Manza Bay) and Fish Eagle Point and coastal forest on Kilulu Hill in Tanzania, as well as from Mrima Hill, Jombo Hill, Kilibasi Hill (co-occurring with I. haematoscelis ), Shimba Hills, Diani, Cha Simba, Godoni Forest, Gogoni Forest, Tiwi, among other sites in Kenya. The measurements given ( Table 11 ) are derived from the long series from Mrima Hill, while drawings of morphology are from the Diani population.

REMARKS

The terminalia of R. obscuripes n. comb. are distinctive (see diagnosis). Minor variations in male genital morphology occur between the different populations assigned to this species, but they all share the widely-spaced and protuberant flanges on the male supra-anal plate ( Fig. 5F). The male specimen from Jadini, Kenya, figured by Johnsen & Forchhammer (1975: 41, fig. 18) as I. haematoscelis , has been assigned to R. obscuripes n. comb. by this character. The genitalia of the unique holotype of R. obscuripes n. comb. are not available for dissection. However, recently collected specimens from Kwale Island in Manza Bay are close to the holotype in terms both of their external morphology and their Mt DNA profile (Price et al, in preparation). Specimens from sub-coastal localities in Kenya (Shimba Hills, Mangea Hill) are also genetically and morphologically more closely similar to this taxon than to any other. Continuing research to characterize the various populations currently assigned to R. obscuripes n. comb. based on DNA and genital morphology, may lead to the recognition of new species.

In synonymizing three species now assigned to Rowellacris Ritchie & Hemp n. gen. under Ixalidium haematoscelis Dirsh (1966: 103-104 , fig. 42) substituted a drawing of the highly characteristic genitalia of an undescribed Rowellacris Ritchie & Hemp n. gen. species from Amani, East Usambara Mts, for the very different genitalia of Ixalidium haematoscelis , which he had apparently never dissected, since no genitalia preparations of his exist in the collections of the NHMUK. This error misled later workers, including Johnsen & Forchhammer (1975).