Guimaraesiella (Guimaraesiella) inaccessibilis, Gustafsson & Bush, 2025

Guimaraesiella (Guimaraesiella) inaccessibilis sp. nov.

( Figs 1 View FIGURES 1–2 , 4 View FIGURES 4–5 , 6–8 View FIGURES 6–12 )

Type host: Nesospiza acunhae Cabanis, 1873 — Inaccessible Island finch.

Type locality: Inaccessible Island , Tristan da Cunha Archipelago, South Atlantic.

Diagnosis. The only other member of the Guimaraesiella interposita species group in which the dorsal preantennal suture does not reach the ads is G. aedon sp. nov. Guimaraesiella inaccessibilis can be separated from G. aedon by the following characters: head proportionately longer and broader in G. inaccessibilis ( Fig. 4 View FIGURES 4–5 ) than in G. aedon ( Fig. 5 View FIGURES 4–5 ); proximal mesosome about as long as broad in G. inaccessibilis ( Fig. 6 View FIGURES 6–12 ), but broader than long in G. aedon ( Fig. 9 View FIGURES 6–12 ); mesosomal lobes with lateral ridge in G. aedon ( Fig. 10 View FIGURES 6–12 ), but no such ridge present in G. inaccessibilis ( Fig. 7 View FIGURES 6–12 ); abdomen of G. inaccessibilis with even yellow pigmentation, but abdomen on G. aedon with medium-brown pigmentation of sternal and subgenital plates, and dark-brown pigmentation on lateral sections of tergopleurites.

Description

Male. Head flat-dome shaped ( Fig. 4 View FIGURES 4–5 ), frons slightly flattened, lateral margins of preantennal area convex. Dorsal preantennal suture reaches dsms but does not reach ads or lateral margins of head. Head chaetotaxy as in Fig. 4 View FIGURES 4–5 . Thoracic and abdominal segments and chaetotaxy as in Fig. 1 View FIGURES 1–2 . Tergopleurites, sternal, and subgenital plates of even yellow pigmentation, darkening only laterally where ventral and dorsal sections of tergopleurites overlap. Male genitalia as in Figs 6–8 View FIGURES 6–12 . Basal apodeme widening proximally ( Fig. 6 View FIGURES 6–12 ). Proximal mesosome about as wide as long, widening slightly anteriorly ( Fig. 7 View FIGURES 6–12 ). Mesosomal lobes triangular, with near-right angles in anterior ends; no ridge near lateral margin; 2 ames and 3 pmes microsetae on each side forming near-continuous lines. Gonopore broad proximally, narrowly open distally; wide rugose area follows proximal margin of gonopore, but does not reach lateral margins of mesosome. Parameral heads large, irregular ( Fig. 8 View FIGURES 6–12 ). Parameral blades slender, tapering; pst1 sensillum, near median margin; pst2 microseta, central. Measurements (n = 2): TL = 1.32–1.53; HL = 0.38; HW = 0.35–0.36; PRW = 0.21–0.23; PTW = 0.33–0.34; AW = 0.38–0.47.

Female. Unknown.

Etymology: The species epithet is derived from the type locality: Latin “ inaccessibilis ” for “not accessible”.

Type material. Ex Nesospiza acunhae : Holotype ♂, Inaccessible Island , Tristan da Cunha Archipelago, South Atlantic, Oct./ Nov. 1988, Peter G. Ryan, L-2 ( NHML). Paratype: 1♂, same data as holotype ( NHML) .