Insularorchestia susorum, Lowry & Myers, 2022

Lowry, J. K. & Myers, A. A., 2022, Platorchestiinae subfam. nov. (Amphipoda, Senticaudata, Talitridae) with the description of three new genera and four new species, Zootaxa 5100 (1), pp. 1-53 : 22-23

Insularorchestia susorum sp. nov.

( 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).

Figures

FIGURE 12. Insularorchestia susorum sp. nov., after Stock & Biernbaum, 1994.