Scirtes elegans

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 : 519

Scirtes elegans species group ( Yoshitomi 2009)

Yoshitomi (2009) defined the S. elegans group as “having the tegmen connected to an asymmetrical penis”. We add: first segment of labial palpus as long as second, mandible incisivus long, metatrochanter elongate, caudal margin of sternite 7 moderately concave. The relationship between tegmen and penis perhaps could be described as having the elements of each complexly intermingled ( Fig. 21 ). Within the group the female of only one species is known—that of the only Australian species, S. albamaculatus , from North Queensland. Assuming that the female of S. albamaculatus is representative of the group we could also add: members are dark coloured with white/cream macula or stripes on the elytra and females with elytral excitators (Fig. 31) and a ring-like bursal sclerite ( Fig. 6 ). No larvae have been described.

The Scirtes elegans group as presently defined has only three species, S. elegans from Malaysia, S. albamaculatus from Australia and S. albotaeniatus Yoshitomi from Guam.

The sequence data place S. albamaculatus as unique within Australian Scirtes . However, it also strongly links S. albamaculatus to S. teruhisai Yoshitomi & Ruta from Borneo ( Fig. 1 ) which is the only representative of the species-rich Southeast Asian S. flavoguttatus group (Yoshitomi & Ruta 2010; Ruta et al. 2014) included in our study. This placement is not unexpected as a number of species currently placed in this group have female excitators, pale colour patterns on the elytra, all have fused tegmen and penis and some, e.g. S. sarawakensis Ruta & Yoshitomi , have an aedeagus approaching the complexity seen in S. albamaculatus . The form of the mandible and labial palpus also point to membership of the S. flavoguttatus group. With the discovery of additional species in the S. flavoguttatus group in Southeast Asia (Ruta et al. 2014) the distinction between these two groups has become rather tenuous and relies on the asymmetric rather than symmetric penis. The strong linkage of S. albamaculatus and S. teruhisai by the sequence data suggests that the two species belong in the same species group. However, with only one species of each group available to us we feel it is premature to formally combine these species groups on the results of this study.

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.