Phylloclusia

Introduction

Distribution of Phylloclusia species. © Owen Lonsdale

Phylloclusia Hendel, 1913 species are slender and yellow with dark stripes and spots and are among the largest Clusiidae (4.5-7.3 mm in length) (Lonsdale & Marshall, 2006).  The genus includes six species found in Japan, Taiwan and Southeast Asia, while its sister group, Tetrameringia McAlpine, 1960 (also found in Japan) has a more southerly distribution, with species described from Madagascar, South Africa, Malawi and eastern Australia (Barraclough, 2000, 2002; McAlpine, 1960; Sueyoshi, 2006; Stuckenberg, 1973).

Little is known of the biology of Tetrameringia and Phylloclusia, but P. darlingi Lonsdale & Marshall has been collected in a log emergence trap, and specimens of Tetrameringia have been collected around creeks and small streams in shaded areas (McAlpine, 1960).  Australian Tetrameringia have also been collected by sweeping over a moist stream bed in an otherwise dry forest.  Immature stages are unknown.

Characteristics

The defining synapomorphies of Phylloclusia include the following: one pair of lateral scutellar bristles; anterior dorsocentral no more than half length of posterior dorsocentral; posterior 1/3 of scutum shiny between dorsocentral bristles; frons shiny, slightly constricted posteriorly, and with anterior margin produced as an elevated ridge; lower ¾ of face brown (sometimes appearing as a central spot); notum elongate with postpronotum bulging (less so in P. lanceola spec. nov.).  Phylloclusia species also have very long prescutellar acrostichal bristles and no dorsal preapical tibial bristles, and the Japanese and Southeast Asian species have a laterally compressed arista (also found in the European Hendelia beckeri Czerny), a long triangular first flagellomere, yellow bristles and a carinate face (Lonsdale & Marshall, 2006).

Phylogenetics

Phylloclusia is considered the sister-group to Tetrameringia in the Clusiinae on the basis of male and female genitalic synapomorphies: posterior margin of male sternite 6 setose; surstylus small, thin and subtriangular; inner surface of surstylus without basal projection; distiphallus broken medially and reflexed; ventral shield of phallapodeme raised from shaft (almost entirely reversed in P. quadrivittata); spermatheca pigmented, irregularly-shaped and with minute transverse grooves (smooth and spherical in T. borealis Sueyoshi); spermathecal duct with subbasal attachment to spermatheca (Lonsdale & Marshall, 2006).  Loss of the hypandrial bristles may be an additional synapomorphy of these genera, but they are also absent in Clusia. 

Externally, both genera differ from other Clusiidae by having inclinate anterior fronto-orbital bristles, two pairs of dorsocentral bristles, a well-developed postvertical bristle, one pair of vibrissae, a small M_1,2 ratio (1.9-2.5), bristles on the posterodorsal surface of the fore femur and no interfrontal or dorsal preapical tibial bristles.  Most species in these genera also usually lack a subnotal stripe and have an irregular row of ventral ctenidial bristles on the male fore and mid femora (Lonsdale & Marshall, 2006).

References

Barraclough, D.A. 2000. The identity of Strongylophthalmyia Heller species (Diptera: Schizophora: Strongylophthalmyiidae) described from the Afrotropical Region, and their transfer to the family Clusiidae. Annals of the Natal Museum, 41: 103-106.

Barraclough, D.A. 2002. A new species of Tetrameringia McAlpine (Diptera: Schizophora: Clusiidae) from Malawi, the third species from the Afrotropical Region. African Invertebrates, 43: 5-10.

Hendel, F. 1913. Acalyptrate Musciden. Clusiinae. Supplementa Entomologica, 2: 77-81.

Lonsdale, O. & Marshall, S.A. 2006. Revision of the genus Phylloclusia (Diptera: Clusiidae: Clusiinae). The Canadian Entomologist (accepted for publication).

McAlpine, D.K. 1960. A review of the Australian species of Clusiidae (Diptera: Acalyptrata). Records of the Australian Museum, 25: 63-94.

Stuckenberg, B.R. 1973. New and little-known Clusiidae (Diptera) from South Africa and Mocambique. Annals of the Natal Museum, 21(3): 579-593.

Sueyoshi, M. 2006. Species diversity of Japanese Clusiidae (Diptera: Acalyptrata) with description of 12 new species. Annales de la Société Entomologique de France, 42(1): 1-26.