Rowellacris usambarica ( Ramme, 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 : 520-521

Rowellacris usambarica ( Ramme, 1929) nom. rev., n. comb.

( Figs 1; 2C, D; 4B; 5G; 13; 21D; Tables 8 ; 9 )

Ixalidium usambaricum Ramme, 1929: 307 .

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

TYPE MATERIAL EXAMINED. — Holotype. Tanzania • ♂; [ Lushoto District], [West] Usambara Mountains, Muafa ; [c 1200-1300 m a.s.l.]; J. Buchwald leg.; DORSA BA000802S01 ; Collection Object 1501239; 1d78f5f7-d185-4827-87e9-ed12890fc309; MfN, Berlin . Paratype. Tanzania • ♂; same collection data as for preceding; DORSA BA000802S03 ; MfN, Berlin; MfN URI:http://coll.mfn-berlin.de/u/d87ebc.

OTHER MATERIAL EXAMINED. — Tanzania • 2 ♂; West Usambara Mts, Wilhelmstal [= Lushoto] ; F. E. Zeuner leg.; NHMUK • 1 ♂; West Usambara Mts, West foot of mountains, Mombo, Riverine forest ; 9.VI.1967; N. D. Jago; DNA voucher B5, extracted 19.X.2022, Box: SA00924142, Tube: FD18757457; NHMUK 015134149 • 1♂; West Usambara Mts, Ndelemai Forest ; III.2022; C. Hemp leg.; Coll. CH • 1 ♂; West Usambara Mts, Muafa [Lushoto District] ; III.2022; C. Hemp leg.; Coll. CH .

DIAGNOSIS. — Basal portion of supra-anal plate with flanges on posterior margin not continuous with outer edges ( Figs 5, G; 13A). Cingulum with well-developed apodemes ( Fig. 13 B-D). Posterior margin of cingulum medially excavated with pointed and sclerotised lateral processes ( Fig. 13B). Sub-dorsal lobe prominently inflated and exposed dorsally, slightly bilobate ( Fig. 13B).

Measurements: Table 8.

DISTRIBUTION

Known only from submontane forest sites at Muafa, Ndelemai Forest, Lushoto and riverine forest at Mombo, West Usambara Mountains. Dissection of the genitalia of the male paratype from Muafa and comparison with recently collected specimens of this species from Muafa and the nearby Ndelemai Forest indicate that R. usambarica n. comb. ( Fig. 13 A-H) has a restricted distribution within the West Usambara Mountains. It is replaced by several other closely-related Rowellacris Ritchie & Hemp n. gen. species, both on neighbouring Eastern Arc mountains and within the West Usambara Mts. The single male paratype collected, along with three females, by Vosseler from Amani (East Usambara Mts) has not been dissected, but numerous other specimens from Amani and its environs, both in the NHMUK collection and collected recently have been dissected. These all show character states in the morphology of the cingulum that are consistently distinct from West Usambara material and all evidently belong to a single species. Accordingly, this Amani material has been assigned to a third, as yet undescribed species of Rowellacris Ritchie & Hemp n. gen. (unpublished data). The single male paratype of I. usambaricum collected by Karasek from Tanga has been dissected and found to belong to the related coastal forest species Rowellacris obscuripes ( Miller, 1929) n. comb. The records of R. usambarica n. comb. from East Usambaras and Mlinga Mountain (Magroto) by Hochkirch (1996: 204) are misidentifications of two different undescribed species of Rowellacris Ritchie & Hemp n. gen. (material studied). The record of I. usambaricum from Lutindi Forest ( Hemp et al. 2016: 216) represents yet another undescribed species of Rowellacris Ritchie & Hemp n. gen. Yet another undescribed species of this genus occurs in the Irente area west of Lushoto.

REMARKS

Ramme (1929: 307-308) described I. usambaricum from a mixed species series here recognised as comprising three distinct species ( Table 9 ). The holotype male and two paratypes, one male and one female, were collected by J. Buchwald at Muafa (West Usambara Mountains).