Ischnostomiella rudebecki, Irish, 2024

Irish, Renzo Perissinotto John, 2024, A new species of Ischnostomiella Krikken, 1978 from the Limpopo Province of South Africa (Scarabaeidae: Cetoniinae, Xiphoscelidini), Fragmenta entomologica 56 (1), pp. 13-20 : 14

Ischnostomiella rudebecki sp. nov.

( Figs 1 , 3 )

Diagnosis. Ischonstomiella rudebecki differs drastically in its chromatic pattern from both species already known in this genus, I. denticeps and I. werneri , which are black to partially brown-orange (but see exception below, under I. denticeps ) by comparison with the prevailing testaceous-orange colour of the new species ( Figs 1-2 ). The pronotum of I. rudebecki also exhibits apical and basal margins substantially more deflected than observed in either of the two oth- er species, with the apical being markedly concave and the basal convex, rather than straight ( Figs 1-2 ). The clypeal denticles of I. rudebecki end up turning slightly outwards, while in the other two species, these are either parallel or inwardly bent, and the apical margin between the denticles is U-shaped in the new species, by comparison with the semicircular shape of I. werneri and the V-shape of I. denticeps (cf. Beinhundner 2005, figs. 2 and 11). Finally, the presence of poorly developed elytral costae 1-5 in I. rudebecki sets this species as intermediate between I. werneri , which completely lacks elytral costae and I. denticeps which conversely shows a marked development in this area ( Figs 1-2 ; cf. Beinhundner 2005, figs 4 and 13). On the oth- er hand, the extremely short protibial spur of I. rudebecki , combined with the rather marked convexity of the lateral margins of its pronotum, makes it closer to I. werneri than to I. denticeps , as perhaps already suggested by their respective geographic distributions ( Fig. 3 ).

Figures

Fig. 1 – Ischnostomiella rudebecki sp. nov., Holotype ♀: A) dorsal habitus; B) ventral habitus; C) lateral habitus; D) clypeus; E) pygidium; F) specimen labels. Photos: John Irish.

Fig. 3 – Distribution range of the three species of Ischnostomiella Krikken, 1978 within the southern African region. (Map: Google Earth Pro with image from Landsat/Copernicus 12/14/2015).

Fig. 2 – A, dark ♂, Namibia, Karibib; B, brown-orange ♂, ibidem; C, dark ♀, Namibia, Omaruru. I. werneri Beinhundner, 2005: D, Holotype ♂, Botswana, Gweta; E, Paratype ♂, ibidem; F, “allotype” ♀, ibidem.