(Fig. 12)
Platorchestia platensis forma monodi.— Stock & Biernbaum, 1994: 797, fig. 1.
Not Orchestia monodi Mateus, Mateus & Afonso, 1986: 100, figs 1–7.
Platorchestia monodi.— Stock, 1996: 150.
Not Orchestia monodi Mateus, Mateus & Afonso, 1986: 100, figs 1–7.
Types. Syntypes, 8 males, 9 females, ZMA. CRUS.A.200676, The Piggery (just below The Peak), altitude c. 762 m, UTM coordinates ES 27170 x 9~2103; under stones, and wood, 11 November 1989.
Other material. GMBL 80-47 a, 8 males, 18 females (including ovigerous specimens), on ridge below the peak of Green Mountain, alt. c. 792 m, in short vegetation consisting largely of the prostrate species Centella asiatica L., 1 August 1980 (USNM). ASC-2, 12, at farm on Green Mountain, alt. c. 759m, 12 July 1976, leg. R. Manning (USNM). 555 additional specimens were obtained, from The Piggery, 760 m, ZMA.
Type locality. The Piggery (just below The Peak), Ascension Island, altitude about 762 m, UTM coordinate ES 57170 X 912103.
Ecological type. Field-hoppers.
Habitat. Terrestrial, living under stones and wood and in short vegetation consisting largely of the prostrate flowering plant Centella asiatica, between 759 and 792 m altitude.
Etymology. Named susorum, an allusion to the type locality, The Piggery on Ascension Island.
Size. 8.5 mm (mature female).
Diagnosis ( male ). Based on Stock & Biernbaum (1994).
Gnathopod 2 propodus palm slightly sinuous in shape, with broad proximal ledge; with shallow midpalmar sinus; dactylus attenuated distally.
Remarks. Although this species is not well described, its characters are distinctive and indicate that this species is referable to the genus Insularorchestia.
Insularorchestia susorum sp. nov. (as Platorchestia platensis forma monodi of Stock & Biernbaum (1994)) was only partially illustrated and not described. Fully mature females with well-developed oostegites, some carrying eggs or juveniles in the brood pouch were 8.5 mm in length.
The peculiar dactylus of male gnathopod 2 (elongate distally and attenuated), no sinus on the palm and nonincrassate pereopod 7 separates it from other species of Insularorchestia.
Distribution. South Atlantic Ocean. Ascension Island (Stock & Biernbaum 1994, Stock 1996).