Pentachaeta skusei, McAlpine, 2014

McAlpine, David K., 2014, Review of the Australian Genus Pentachaeta (Diptera: Heleomyzidae), with Descriptions of Nine New Species, Records of the Australian Museum 66 (5), pp. 247-264 : 257-258

publication ID 10.3853/j.2201-4349.66.2014.1631

persistent identifier

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scientific name

Pentachaeta skusei

sp. nov.

Pentachaeta skusei n. sp.

Figs 26–29 View Figures 26–29

Type material. Holotype ♂. Victoria: Belgrave, near Melbourne , [probably margin of Sherbrooke Forest, c. 37°53'S 145°22'E], 21.i.1966, D.K.M. ( AM K310595 ). Glued to card point, postabdomen in genitalia tube on same pin GoogleMaps . Paratypes. Victoria: 2♂♂, Ninks Road, Kinglake , Jan 1980, B.W.B. ( ANIC) . New South Wales: 1♂, below Govett’s Leap, Blue Mountains , Dec. 1956, D.K.M. ( AM) .

Description (male)

Resembling P. edwardsi and related species without sexual dimorphism of tibiae; agreeing with description of that species, except as indicated below.

Coloration generally as for genus; details as given for P. edwardsi except as here noted. Fore femur orange-tawny, becoming brownish dorsally (perhaps faded in old type specimens); fore tarsus with segments 1 and 5 brown or largely brown, segments 2 to 4 pale tawny-yellow; mid tarsus tawny yellow, indistinctly brownish distally in faded specimens; hind tarsus dark brown.

Abdomen. Surstylus ( Fig. 26 View Figures 26–29 ) ovate-lanceolate, distally gradually tapering to obtuse apex, outer surface extensively microtrichose, also with scattered short but rather stout setulae, which may be more numerous on posterior part of outer surface, apical part of inner surface with few setulae of variable size and marginal group of minute setiferous tubercles, at base of inner surface fascicle of short, stout setulae, either not arising from a common prominence, or on very slight prominence; subepandrial process ( Fig. 29 View Figures 26–29 ) with numerous stout setulae towards apex and on inner surface; apex of gonostylus with three or four large setulae and sometimes few much smaller ones, with flat or slightly concave posterodistal densely pustulose zone; bulb of aedeagus without invaginated teeth; cercus ( Figs 27, 28 View Figures 26–29 ) narrowly extended posteriorly, much broadened across base of anterior lobe, with pair of anterior lobes strongly divergent, at broadest part with prominent dorsal (and thus partly concealed) setulose tubercle ( Figs 27, 28 View Figures 26–29 ), on exposed ventral surface with extensive armature of large setulae, becoming sparser and finer on anterior lobe.

Dimensions. Total length 3.2 mm; length of thorax, 1.3–1.6 mm; length of wing, 3.4–4.0 mm.

Distribution. New South Wales: Blue Mountains. Victoria: forested areas E and NE of Melbourne. Map references 4L, 7J ( Fig. 4 View Figure 4 ).


Pentachaeta skusei belongs among those species without sexual dimorphism of the tibiae and with the fore tibia tawny yellow with brown apex. It differs from other such species in having segments 2 to 4 of the fore tarsus tawny yellow (dark brown in related species). The form of the surstylus ( Fig. 26 View Figures 26–29 ) is distinctive, though somewhat resembling that of P. gilliesi , but the male cercus is very different (compare Figs 27 View Figures 26–29 and 30 View Figures 30–33 ). I suspect that the unknown female will be distinguishable from related species by the coloration of the fore tibia and tarsus, as in the male.

This species is dedicated to Frederick A. Skuse, the first Diptera specialist employed at the Australian Museum.


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