Eupelmus (Eupelmus) guamensis (Yoshimoto & Ishii) Yoshimoto & Ishii, 2017

Gibson, Gary A. P., 2017, Synonymy of Reikosiella Yoshimoto under Merostenus Walker (Hymenoptera: Chalcidoidea: Eupelmidae), with a checklist of world species and a revision of those species with brachypterous females, Zootaxa 4255 (1), pp. 1-65 : 60

Eupelmus (Eupelmus) guamensis (Yoshimoto & Ishii) n. comb.

Figs 140–143

Merostenus guamensis Yoshimoto & Ishii, 1965: 159 –161. Holotype ♀ (USNM; type no. 67528).

Type material. This species was based on three females, the holotype in USNM and two paratypes in BPBM. The holotype is labelled “ Guam I., Marianas | 30 March 1948 / Pacific Sci. Board | Ent. Survey of | Micronesia | H.S. Dybus leg / HOLOTYPE Merostenus guamensis Yoshimoto & Ishii [red label, partly printed and partly handwritten]”. It is point-mounted, uncontorted, and entire ( Figs 140, 141 ).

Remarks. Although the generic assignment of E. guamensis is obvious, its subgeneric classification is less certain. Gibson (1995) differentiated E. ( Eupelmus ) from E. ( Macroneura ) by females of the latter subgenus displaying apomorphic structures of the pronotum, metanotum and propodeum. Female E. ( Macroneura ) have a distinct, transverse pronotal ridge or crest. Furthermore, the metanotum is comparatively large and flat, though more or less concave posterior to the scutellum, and the propodeal plical region has at most a flat, inconspicuous Vshaped plical region. Pronotal structure of E. guamensis is characteristic of E. ( Eupelmus ) females, lacking both a transverse pronotal ridge or crest and a transverse line of long dark setae on the more convex, anterior part of the collar, though there are long dark setae within the posteriorly concave portion. The fore wings largely conceal the metanotum and propodeum in the holotype ( Fig. 140 ) and the Piti paratype is contorted so that the structures are not visible. However, the Barrigada paratype has a metanotal-propodeal structure ( Fig. 143 ) that is at least superficially similar to that characteristic of E. ( Macroneura ) females. Though the metanotum is transverse, obviously wider posteriorly than long laterally, posteriorly there is a transverse-rectangular horizontal region below the level of the propodeum, and anteriorly the metanotum is right-angle bent upwards medially behind the scutellum. Thus the metanotum can be construed as being “concave” behind the scutellum. The propodeal plical region is also strongly transverse with an almost vertical, broad, slender depression behind and above what appears to be a medially differentiated part of the posterior, horizontal part of the metanotum. I suspect the metanotalpropodeal similarities with E. ( Macroneura ) females are convergent and the immediate ancestor of E. guamensis was some macropterous species of E. ( Eupelmus ).

The dorsal and lateral habitus line illustrations given by Yoshimoto & Ishii (1965, fig. 26) are accurate for structure, but insufficient for sculpture and wing setal pattern. The spatulate, hyaline fore wings ( Figs 140, 143 ) are entirely setose with white setae except the costal cell is bare dorsally, the submarginal vein has conspicuously long setae (the longest subequal in length to about 1.2× as long as width of the wing), and there are shorter though still long setae along the leading margin of the wing from about the apex of the costal cell. The frontovertex ( Fig. 142 ) is finely meshlike coriaceous whereas the mesoscutum and scutellar-axillar complex are similarly meshlike reticulate, and the gaster, although quite densely setose with comparatively long, dark setae, is only finely meshlike coriaceous. Mesotibial apical pegs are lacking.

Figures

FIGURES 140 – 143. E. (Eupelmus) guamensis (Yoshimoto & Ishii) ♀. 140 – 142, holotype: 140, dorsal habitus; 141, lateral habitus; 142, head, frontal. 143, Barrigada paratype, scutellar-axillar complex to propodeum plus wings.