Myopias chapmani

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Myopias chapmani
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Myopias
Species: M. chapmani
Binomial name
Myopias chapmani
Willey & Brown, 1983

Myopias chapmani casent0172093 profile 1.jpg

Myopias chapmani casent0172093 dorsal 1.jpg

Specimen labels

The type colony was found in "a small nest in a thick fragment of a rotten branch lying on the ground in wet rain forest along" a creek. There were 20-30 individuals, with multiple queens, in the nest.

Identification

Willey and Brown (1983) - Worker: A modest-sized member of the tenuis goup; head large, nearly square, with sides almost straight and nearly parallel; posterior margin concave. Eyes small but distinctly facetted. Mandibles rather short and stout; antennal scapes distinctly overreaching posterior border of head. Trunk robust, with broad and deeply impressed metanotal groove; propodeal dorsum less than twice as long as mesonotum. Node of petiole higher and wider than long, convex above. Gaster distinctly constricted between first and second segments. Sculpture predominantly smooth and shining, with spaced, indistinct punctures, especially on head, but sides of propodeum obliquely costulate, subopaque; dorsal propodeal surface finely roughened in part, and bearing a few, coarse, indistinct grooves and punctures, as well as a weak impression just caudad of its midlength. Color light ferruginous red.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Australasian Region: Australia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Queen

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • chapmani. Myopias chapmani Willey & Brown, 1983: 264, figs. 10, 26 (w.q.) AUSTRALIA.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Holotype: TL 5.7, HL I.l2, HW 1.07 (CI 96), ML 0.57 (MI 51), MLO 0.87, SL 0.95 (SI 89), EL 0.1 I, WL 1.77, hind femur L 1.06, hind tibia L 1.00 mm.

Paratypes (21 from type nest series) range downward from the size of the holotype to the smallest individual, which has TL 5.2, HL 1.03, HW 0.98 (CI 95), ML 0.54 (MI 52), MLO 0.81, SL 0.86 (SI 88), EL 0.1 I, WL 1.63, hind femur L 0.94, hind tibia L 0.86 mm.

Head massive, sides only feebly convex, widest at posterior edge of eyes and tapering almost imperceptibly to rather abruptly rounded posterior corners; posterior border moderately concave across its middle half. Eyes almost round, with about 17 or 18 facets, each situated nearly twice its own diameter away from mandibular insertion; an indistinct groove extends the dorsal (mesal) orbital groove forward onto clypeal wing. Median clypeal lobe slightly longer than wide (CLL 0.14, CLW 0.13 mm), widest near apex, its anterior margin convex and free corners rounded. Median frontal sulcus wide and deep, extending back to posterior third of HL.

Antennal scapes slender, gently bowed, slightly incrassate apicad, overreaching the posterior border of the head by about the same as their apical width when held straight back in dorsal full-face view of head. Funiculus slender. but with an indistinctly 4-merous club; all antennomeres longer than wide; funiculus I about twice as long as II. Mandibles robust, rather short, with a sharp apical tooth and a minute adjacent companion tooth; one subapical and one submedian tooth each isolated, blackened and rounded; basal angle present, but low and rounded. Oblique basal groove and its lateral continuation very distinct. Labral lobes each bearing a delicate, upturned apical tooth, practically impossible to see without dissection. Palpi segmented 3,3; basal maxillary palpomere short and broad, last two subequal in length, but apical broader, fusiform, with apical sensillum; labial palpomeres all slender, the apical slightly longer and thicker than the basal two, and with an apical sensillum.

Trunk robust, divided by a broad and deeply impressed metanotal groove into a promesonotal portion and a shorter propodeal portion. Mesonotum convex, rising above pronotum, sloping caudad, nearly 2/3 as long as propodeal dorsum; propodeum weakly convex, but with a feebly impressed area in the posterior half of its dorsum (variably distinct in paratypes); dorsum rounded unevenly into declivity and with a feeble median impression at the point where they meet; declivity more or less flat, with lateral boundaries distinct, almost submarginate.

Petiolar node distinctly higher than long, its curved dorsal face highest behind the mid length; anterior face in side view straight or feebly concave, sloping caudad; posterior face convex in side view, sloping cephalad. In dorsal view, anterior cornuae of node very prominent; node widest behind, with convex sides, slightly wider than long. Postpetiolar (gastric I) segment slightly broader than long; its anterodorsal border feebly concave in the middle; gastric II a little wider than I, but equal in depth in side view after a distinct constriction between the two that is boldly scrobiculate. Sting long and sharp, gently upcurved (found extended up to 0.60 mm in various specimens.

Sculpture mainly smooth and shining, with mostly inconspicuous, separated, piligerous punctures, distributed as follows: on dorsum of head, on each side of midline, numerous small ones, averaging about 0.01 mm in diameter, or smaller, mostly in the space between eye and median sulcus; small punctures distributed sparsely on mandibles, back and sides of head, fore coxae, pronotum, mesonotum, and gastric tergum II. Moderately coarse, often elongate, punctures on propodeal dorsum, petiolar node and first gastric tergum. Antennae and legs largely smooth and shining, but with very fine punctulation, increasing toward extremities. Sides of propodeum with fine, partly broken, oblique costulation, rising caudad, surface here subopaque, giving way on dorsal surface to some partial, roughened microsculpture that renders the surface between coarse punctures only weakly shining. Upper propodeal declivity feebly, finely, transversely strigulose, smooth and shining below.

Pilosity consisting of fine, tapered, erect to suberect setae of uneven length, mostly 0.03 to 0.25 mm long, distributed abundantly over dorsal surfaces of body, venter of head, and gaster, fore coxae, and most surfaces of appendages. Decumbent pubescence is dilute on dorsum of head, directed mesad; more dense on anterior surfaces of mid coxae, and on all tibiae and tarsi.

Color rich, light, ferruginous red; appendages slightly lighter.

Worker variation, apart from the slight mensurable spread, is weak. As already mentioned, the feeble impression, or “saddle,” in the posterior dorsal surface of the propodeum varies from distinct to almost absent in different workers.

Queen

Dealate: TL 5.2, HL 1.00, HW 1.00 (CI 100), ML 0.55 (MI55), MLO 0.77, SL 0.84 (SI84), EL 0.23, WL 1.65, hind tibia L 0.81 mm. Notable for size being slightly smaller than for workers of the same colony. Otherwise, differences are those usual between castes in Ponerini. Nota of pterothorax smooth and shining, with dispersed, small punctures. Propodeum more completely and strongly sculptured than in worker, subopaque, finely transversely strigulose, with a short, longitudinal, median sulcus or impression; lower declivity smooth. Color slightly darker than in worker, especially lightly infuscated parts of cranium, pronotum, median scutum, propodeum, petiole, and first two gastric segments.

Type Material

Holotype worker (MCZ) and paratypes (MCZ, BMNH, ANIC) from a small nest in a thick fragment of a rotten branch lying on the ground in wet rain forest along Obi Obi Creek, below and just west of Montville, Blackall Range, Queensland, Australia, 20 May, 1951, leg. Brown. The nest contained 20-30 workers, larvae (since lost together with prey remains), and two dealate queens. The forest at the type locality has since been destroyed (fide P.J. Darlington, personal communication).

  • Holotype, worker, west of Montville, Obi Obi Creek, Blackall Range, Queensland, Australia, Museum of Comparative Zoology.
  • Paratype, 6 workers, west of Montville, Obi Obi Creek, Blackall Range, Queensland, Australia, Museum of Comparative Zoology.
  • Paratype, queen(s), west of Montville, Obi Obi Creek, Blackall Range, Queensland, Australia.

Etymology

The species is named for the late Dr. James W. Chapman, who collected many Myopias series in the Philippines.

References