Scirtes helmsi, Blackburn, 1892

Watts, Chris H. S., Cooper, Steven J. B. & Saint, Kathleen M., 2017, Review of Australian Scirtes Illiger, Ora Clark and Exochomoscirtes Pic (Coleoptera: Scirtidae) including descriptions of new species, new groups and a multi-gene molecular phylogeny of Australian and non-Australian species, Zootaxa 4347 (3), pp. 511-532 : 520

Scirtes helmsi species group ( Watts 2004)

Defined here as: broadly oval; mandible incisivus relatively short, first segment of labial palpus shorter than second, caudal margin of metacoxal plates straight or nearly so, caudal margin of sternite 7 truncated rather than concave, metatrochanters elongate-oval, 2.0× as long as wide, aedeagus asymmetrical, pala well developed, one or two parameroids, typically the right hand one longer and with an apical hook; tegmen variable, usually simple, parameres simple, usually long and thin but sometimes broader and tending to wrap around the penis but are never fused with it ( Watts 2004) ( Figs 18–20 ); female coxites and styles elongate, prehensor moderately developed, occasionally absent, basal sclerite typically pelican-bill-like but occasionally ring-shaped with internal prongs or bullet-shaped with internal spines ( Figs 7–16 ). Larva with maxillary palpus four-segmented, five anal papillae and mandible with single-pointed incisivus.

Most of the species of Australian Scirtes studied fell into this group. The sequence data identified two major subgroupings with some internal substructure within each. There is no correlation between the different female prehensors and bursal sclerites and the sequence data. The male terminalia of S. zwicki are quite unlike those of other species in the group (and from any other known Scirtes species), having elongate, symmetrical genitalia and a greatly modified sternite 9. Sternite 8 appears to be missing ( Fig. 23 ). Genetically it is unequivocally within the S. helmsi subgroup ( Fig. 1 ).

There are 27 described species in the Scirtes helmsi group in Australia ( Watts 2004 & this paper). Yoshitomi & Ruta (2010) noted the close similarity of 11 New Caledonian species with Australian species. From the illustrations of the male genitalia, S. babeldaobensis Yoshitomi from Micronesia in Yoshitomi (2009) and possibly S. zerchei Klausnitzer from Luzon Island may also belong in the S. helmsi group.

Figures

FIGURE 1. Phylogenetic tree of Australian Scirtes, Ora, Exochomoscirtes and some related Asian species, based on Bayesian inference (BI) analysis of concatenated sequence data of COI, EF 1 - a and TOP 1. A tree with identical topology was obtained using ML analyses of the same data set and a concatenated dataset comprising only COI and TOP 1. Numbers on branches give posterior probabilities (left) from BI analyses and bootstrap proportions (right) as a percentage of 500 pseudoreplicates from a ML analysis.

FIGURES 17 – 22. Tegmen and penis of: 17) Scirtes auratus; 18) S. serratus; 19) S. interstinctus; 20) S. lynnae; 21) S. albamaculatus. 22) Penis of S. pinjarraensis.

FIGURES 6 – 10. Prehensor and bursal sclerite of: 6) Scirtes albamaculatus; 7) S. exoletus; 8) S. nigerpalpus; 9) S. orientalis; 10) S. zwicki.

FIGURES 11 – 16. Prehensors and bursal sclerites of: 11) Scirtes helmsi; 12) S. brisbanensis; 13) S. peniculus; 14) S. pinjarraensis; 15) S. storeyi; 16) S. triangularis.

FIGURES 23 – 28. 23) Male terminalia of Scirtes zwicki: a) tergite 8, b) tergite 9, c) sternite 9, d) trigonium, e) tegmen. 24) Habitus photograph of Scirtes zwicki; 25) ditto, ♀ S. albamaculatus. 26) Clypeolabrum of last instar larva of S. lynnae; 27) ditto, S. serratus; 28) ditto, S. triangularis.