Rowellacris transiens ( 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 : 522-523

Rowellacris transiens ( Ramme, 1929) n. comb.

( Figs 5D, E; 14; Table 10 )

Ixalidium transiens Ramme, 1929: 308-309 .

Ixalidium haematoscelis – Dirsh 1966: 103 (incorrectly synonymised. Recalled from synonymy by Johnsen & Forchhammer [1975: 38-41]).

TYPE MATERIAL EXAMINED. — Holotype. Tanzania • ♂; [ Lushoto District], [East] Usambara, Nguelo [Ngwelo] ; [ 4°44’S, 38°29’E]; [Ernst?] Heinsen leg.; MfN .

‘Allotype’ [ Paratype]. Tanzania • ♀ [ Lushoto District], [East] Usambara, Nguelo [Ngwelo] ; [ 4°44’S, 38°29’E]; [Ernst?] Heinsen leg.; MfN .

OTHER MATERIAL EXAMINED. — Tanzania • All material: Lushoto District, East Usambara Mountains • 6 ♂, 3 ♀, 3 nymphs; Soni ; 4°51’S, 38°22’E; 17.IX.1950; J. Phipps leg.; NHMUK • 2 ♂, 1 ♀; Kihuhwi Bridge, 7 miles East of Amani ; 5°13’S, 38°41’E; 27.VIII.1937; E. Burtt leg.; NHMUK • 1 ♂; Kihuhwi Bridge, 7 miles East of Amani ; 5°13’S, 38°41’E; 28.VIII.1938; E. Burtt leg., NHMUK . • 1 ♂; Kwamtili Plantation ; 4°55’S, 38°44’E; III.1952; J. Phipps leg.; NHMUK • 5 ♂, 4 ♀, 2 nymphs; Sigi, nr Amani ; 5°6’S, 38°39’E; 18-31.XII.1965; N. D. Jago leg.; NHMUK • 2 ♂, 1 ♀; Sigi, nr Amani ; 5°6’S, 38°39’E; 2-11.IV.1966; N. D. Jago leg.; NHMUK • 1 ♂; Bomole Summit, near Amani ; 5°6’S, 38°37’E; 3.IV.1966; N. D. Jago leg.; NHMUK • 1 ♂, 1 ♀; Longuza Forest Reserve ; 5°4’S, 38°41’E; 15.IV.1966; N. D. Jago leg.; NHMUK • 1 ♂; Derema Forest ; 5°38’S, 37°30’E; 24.XII.1965; N. D. Jago leg.; NHMUK • 1 ♂; Amani, Amani Nature Reserve, nr HQ ; 5°5’S, 38°40’E; VII.2016; C. Hemp leg.; submontane forest; Coll. CH • 1 ♂; Amani, Waldrand (forest edge) ; 5°5’S, 38°40’E; X.2002; C. Hemp leg.; Coll. CH • 1 ♂; Sigi, trail at night; 5°6’S, 38°39’E; III.2012; C. Hemp leg.; Coll. CH .

DIAGNOSIS. — Male terminalia of unique form, with projecting medial furcula ( Fig. 5D, E). Cingulum with well-developed apodemes with expanded tips ( Fig. 14 G-I). Posterior margin of cingulum medially excavated but lacking lateral processes ( Fig. 14G, H). Sub-dorsal lobe prominently inflated and exposed dorsally, but unilobate ( Fig. 14G, H).

Measurements: Table 10.

DISTRIBUTION

R. transiens n. comb. is known only from relict forest patches around Amani, East Usambara Mountains, where Hochkirch (1996) reported the species from 11 different survey sites and considered R. transiens n. comb. to be an indicator species for intact forest canopy ( Hochkirch 1996: 209). Hochkirch (2014) gave the name drumming grasshoppers to members of the genus Ixalidium , based on drumming observed in R. transiens n. comb. However drumming behaviour has not been observed in Ixalidium sjostedti and Ixalidium sp. from the North Pare Mts. in recent experiments by one of us ( CH), whereas it is has been observed in both Rowellacris Ritchie & Hemp n. gen. and Tangana (see Bioacoustics). The conservation status of R. transiens n. comb. was assessed as vulnerable by Hochkirch (2014, 2020) and Gereau et al. (2016) due to forest destruction.

HISTORY

Ramme (1929: 311) reported that his Ixalidium (now Rowellacris Ritchie & Hemp n. gen.) transiens represented a transitional stage between Ixalidium usambaricum and Tangana asymmetrica , because of the presence of a furcula on tergite 10 ( Fig. 5D, E), which he considered a precursor to the asymmetric prong in Tangana ( Fig. 5H). However the furcula is an autapomorphy of R. transiens and the genital morphology of this species and all other Rowellacris Ritchie & Hemp n. gen. species is otherwise very consistent and quite distinct from that of Tangana . Johnsen & Forchhammer (1975: 38- 41) correctly recalled this species from Dirsh’s (1966: 103) synonymy under I. haematoscelis and figured the distinctive male external and internal genitalia. Ramme’s unique holotype male of I. transiens has the apical section of the supra-anal plate deflexed into the abdomen ( Ramme 1929: fig. 31) and completely covered by the subgenital plate (see Fig. 14C, D), which led Johnsen & Forchhammer (1975) to believe that the tip was missing.