Pentachaeta pinguis, 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: 261-263

publication ID 10.3853/j.2201-4349.66.2014.1631

persistent identifier

treatment provided by


scientific name

Pentachaeta pinguis

n. sp.

Pentachaeta pinguis   n. sp.

Figs 1 View Figure 1 , 40–42 View Figures 40–42

Type material. Holotype ♂. New South Wales: Royal National Park, lower end of Waterfall Creek , 34°09'S 151°01'E, 25.xii.2003, D.K.M. ( AM K310599). Glued to card point, postabdomen in genitalia vial on same pin GoogleMaps   . Paratypes. New South Wales: 2♂♂, 2♀♀, same locality as holotype, Mar., Dec., 2003–2012, D.K.M. ( AM, ANIC) GoogleMaps   ; 1♂, 2♀♀, [Royal] National Park , Nov. 1960 –1965, D.K.M. ( AM)   ; 2♂♂, 12♀♀, Terania Creek, near Lismore , Feb. 1980 – 1983, D.K.M., B.J.D., K.C.K. ( AM)   ; 1♂, Whian Whian State Forest, near Lismore , Feb. 1965, D.K.M. ( AM)   ; 1♂, Iluka Rain Forest Reserve , Feb. 1965, D.K.M., R.L. ( AM)   ; 2♀♀, Mooney Mooney Creek, near Gosford , Dec. 1976, 1978, D.K.M. ( AM)   ; 4♂♂, 4♀♀, Springwood [probably vicinity of Sassafras Gully], Jan. 1956, D.K.M. ( AM)   .

Other material examined. Queensland: Eungella National Park (near Broken River) ( AM); Olmara Hills, near Dalrymple Heights (or Eungella), c. 1000 m ( AM, QM); Crediton, near Eungella ( AM); Finch Hatton, 180 m ( AM); Finch Hatton Gorge ( AM); 13 km and 17 km S of Ravenshoe ( AM); Edge Hill, near Cairns ( AM); Kuranda ( AM); Paluma ( AM); Austral Forest, near Bulburin, Monto district ( AM).

Description (male, female)

Resembling P. kirkspriggsi   in most characters; agreeing with description of that species, except as indicated below.

Coloration. Antenna tawny-yellow as in P. kirkspriggsi   (type colour form), or with segments 2 and 3 quite black (dark tropical colour form); palpus tawny yellow with c. distal quarter grey brown (darker in fresh specimens), black in dark tropical form. Fore tibia entirely tawny-yellow (type colour form) or with brownish apical zone (dark tropical form).

Thorax. Tibiae as in P. kirkspriggsi   .

Abdomen (male) resembling that of P. kirkspriggsi   except as indicated. Surstylus often slightly more slender than in P. kirkspriggsi   with smaller setulae; subepandrial process slightly narrower distally than in P. kirkspriggsi   , but somewhat variable ( Fig. 42 View Figures 40–42 ); gonostylus with posterodistal group of prominent tubercles and one to three large setulae; cercus slightly variable in shape but differing from that of P. kirkspriggsi   in having anterior lobe tapered, not markedly produced and compressed, but slightly variable in shape.

Dimensions. Total length, ♂ 2.3–3.2 mm, ♀ 2.2–3.1 mm; length of thorax, ♂ 1.3–1.5 mm, ♀ 1.3–1.6 mm; length of wing, ♂ 3.0– 3.3 mm, ♀ 3.0– 3.6 mm.

Distribution. Eastern New South Wales: coastal districts and Blue Mountains; Queensland: Monto district in south of state (type colour form), sub-coastal ranges in tropics, from Kuranda to Clarke (Eungella) Range (mainly dark colour form). Map reference 7F, 7J, 7K, 8H ( Fig. 4 View Figure 4 ).


Pentachaeta pinguis   differs from other species of the genus except P. impar   in having the palpus conspicuously darkened apically, but differs from that species in lacking the brown zone on the upper margin of the sternopleuron. Males resemble those of P. kirkspriggsi   and P. physopus   in having all tibiae conspicuously thickened but differ in the shape of the cercus (compare Figs 41 View Figures 40–42 , 44 View Figures 43, 44 ), whereas the male of P. impar   has only the hind tibia thickened and, again, a differently shaped cercus (compare Figs 40 View Figures 40–42 , 35 View Figures 34, 35 ).

Tropical populations of P. pinguis   differ from all other Pentachaeta   forms in having antennal segments 2 and 3 black. This is such a striking feature that I initially assumed these populations to represent a distinct species, but comparison of numerous specimens from both tropical and southern populations reveals no identifiable differences except in coloration. There is slight variation in the shape of the surstylus and cercus in both these populations, but the male cercus is consistently distinct from that of P. kirkspriggsi   , and both surstylus and cercus are sharply different from those of P. physopus   .

One male specimen of P. pinguis   from within its tropical habitat (Eungella National Park) shows tawny-yellow antennae, but was preserved in alcohol before drying and mounting. It shows some bleaching of pigmented cuticle, and it is uncertain if this treatment fully explains the antennal coloration.

The specific epithet is a Latin adjective, obese or fat, in reference to the thickened male tibiae.


Australian Museum


Australian National Insect Collection


Queensland Museum