Proceratium japonicum

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Proceratium japonicum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Proceratiinae
Tribe: Proceratiini
Genus: Proceratium
Species: P. japonicum
Binomial name
Proceratium japonicum
Santschi, 1937

Proceratium japonicum P casent0281854.jpg

Proceratium japonicum D casent0281854.jpg

Specimen Label

Synonyms

Nothing is known about the biology of Proceratium japonicum.

At a Glance • Larval Hemolymph Feeding  

 

Identification

A member of the silaceum clade and resembling Proceratium numidicum, but differing from it, in the worker and gyne, by the narrower frontal carinae, by broader petiole and by the more impressed body sculpture.

Keys including this Species

Distribution

Japan and Taiwan.

Distribution based on Regional Taxon Lists

Oriental Region: Taiwan.
Palaearctic Region: China, Japan (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Very little is known about the biology of Proceratium ants. They nest in soil, rotten wood, under deep-set stones and, in a few cases, tree branches. For many species the nest consists of small rounded chambers hollowed out of soft rotten wood or in the soil. Toward the cooler limits of the range, particularly in North America, nests and foraging workers are found under deep set rocks instead of in rotten wood. The nest site is usually in forest shade, in old moist gardens, or similar habitats that are constantly moist. Some species of known to be egg predators of arthropods, especially of spiders.

Most Proceratium are relatively rare but this is not the full explanation for why they are not commonly collected. Colonies of most species are small. Based on anectdotal natural history information from a few species, it was once thought that most Proceratium would likely be found to have mature colonies that contain somewhere between 10 - 50 workers. Yet nests with more than 50, and in some cases up to 200, workers have been been reported. Besides small colonies, these ants also do not appear to forage in places where they are readily encountered.

Males and females are though to be produced in small numbers but we generally do not have enough data for colonies of any species to know what might be typical. Reproductive flights have been observered toward the end of the summer in some northern temperate areas. In these regions the nuptial flight occurs during the last half of August. Both sexes climb some distance from the nest entrance before taking flight. Workers too issue from the nest during the nuptial flight, as is often the case with otherwise cryptobiotic ants.

Castes

Worker

Nomenclature

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

  • japonicum. Proceratium japonicum Santschi, 1937h: 362, fig. 1 (w.) JAPAN. Onoyama & Yoshimura, 2002: 35 (q.m.). Senior synonym of formosicola: Onoyama, 1991: 695. See also: Baroni Urbani & De Andrade, 2003b: 368.
  • formosicola. Proceratium formosicola Terayama, 1985c: 406, figs. 1-4 (w.q.) TAIWAN. Junior synonym of japonicum: Onoyama, 1991: 695.

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

Description

Worker

Baroni Urbani and de Andrade (2003) - Head slightly longer than broad and with weakly convex sides. Vertex in full face view gently convex. Clypeus reduced, slightly surpassing the antennal sockets. Anterior border of the clypeus truncate. Frontal carinae far from each other, slightly covering the antennal insertions. Lateral expansions of the frontal carinae little raised, diverging on the two anterior fourths, converging on the third fourth, subparallel and carinate only on the last fourth. Frontal area gently concave on the three anterior fourths and with a central longitudinal carina starting from the last fourth and prolonging posteriorly. Head anterolaterally with a thick, short, longitudinal carina. Genal carinae distinct, each carina corresponding to the external border of a deep sulcus. Eyes visible as a dark dot below the integument, small and on the middle o l the head sides. First funicular joint slightly longer than broad. Funicular joints 2-10 broader than long. Last funicular joint as long as the sum of joints 7-10. Scapes short of the vertexal margin and gently thickening apically. Masticatory margin of the mandibles with 9-11 denticles before the pointed apical tooth. Palp formula 2,2.

Mesosoma in profile convex anteriorly, declivous posteriorly and shorter than the maximum head length (mandibles included). Pronotal and propodeal sutures absent. Basal face of the propodeum declivous posteriorly. Declivous face of the propodeum flat. Area between basal and declivous faces of the propodeum gently concave, less carinate dorsally than in numidicum and laterally angulate or denticulate. Sides of the declivous face of the propodeum carinate. Propodeal spiracle round and above mid height in lateral view.

Petiole subrectangular, broader than in numidicum. Anterior border of the petiole straight and anterolaterally carinate. Posterior broader of the petiolar node gently convex or subangulate. Ventral process of the petiole lamelliform and directed backwards. Postpetiolar sternite anteromedially with a marked subtriangular projection, gently convex posteriorly in side view. Constriction between postpetiole and gaster impressed. Gastral tergite I about 1/3 longer than the postpetiole and convex on the curvature. Remaining gastral tergites and sternites curved ventrally.

Legs not very short. All tibiae with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/4 shorter than hind tibiae. Second tarsomere of hind legs shorter than pretarsus. Pretarsal claws simple. Arolia absent.

Sculpture. Head reticulate-punctate and rugulose, the reticulation and the rugosities broader on the sides. Mesosoma, petiole and postpetiole punctate, the punctures smaller on the anterior half of the mesosoma. Posterior half of the mesosoma and sides of the postpetiole with additional, irregular reticulation. Gaster smooth and with minutely piligerous punctures, the punctures denser and mixed with superficial reticulation on the sides. Legs punctate.

Body covered by hairs of three main types: (1) short, dense, suberect or subdecumbent on the whole body, sparse on the funicular joints; (2) longer than type (1), erect on the whole body, absent on the funiculi; (3) shorter than hair type (1), dense and decumbent on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, sparse hairs, and the scapes with sparse hairs similar to type (2) but slightly shorter.

Colour. Yellow to brown with slightly lighter antennae and legs. Some specimens have the posterior half of the head dorsum darker.

Measurements in mm and Indices: TL 2.84-3.32; HL 0.63-0.75; HW 0.59-0.71; EL 0.03-0.07; SL 0.42-0.49; WL 0.78-0.91; PeL 0.19-0.24; PeW 0.30-0.35; HFeL 0.47-0.56; HTiL 0.38-0.46; HBaL 0.29-0.34; LS4 0.33-0.41; LT4 0.65-0.75; CI 93.6-94.7; SI 64.6-66.6; IGR 0.51-0.55.

Queen

Baroni Urbani and de Andrade (2003) - Differing from the worker in the following details: eyes large, ¼ of the head length, composed by many facets and with ocular pilosity. Ocelli well developed.

Mesosoma robust and convex in side view. Parapsidal furrows masked. Scutellum with the sides gently converging posteriorly and with the posterior border round. Dorsum of the scutellum with a longitudinal carina prolonging to the posterior half of the mesonotum. Metanotum with a pointed tooth. Basal face of the propodeum medially concave. Area between basal and declivous faces of the propodeum carinate and with a small tooth on each side.

Fore wings of our type 4, hind wings of our type 2 and 3 as defined in the description of the genus.

Measurements in mm and Indices: TL 3.48-3.75; HL 0.69-0.73; HW 0.67-0.72; EL 0.19-0.24; SL 0.47-0.49; WL 0.98-1.10; PeL 0.24-0.26; PeW 0.38-0.40; HFeL 0.58-0.60; HTiL 0.47-0.48; HBaL 0.38-0.39; LS4 0.46; LT4 0.84-0.86; CI 97.1-98.6; SI 67.1-68.1; IGR 0.53-0.55.

Male

Baroni Urbani and de Andrade (2003) - Head as broad as long or slightly broader than long. Vertex in full face view convex. Vertexal margin carinate. Clypeus dorsally variably convex and with subround or straight anterior border. Frontal carinae thin, low and parallel. Frontal area concave; postero-lateral borders of the concavity variably marginate, the margins converging posteriorly and connected to a longitudinal carina. Ocelli large. Compound eyes large and situated mostly on the anterior part of the head sides. Scapes not reaching the anterior ocellus. First funicular joint about as broad as long and 1/3 shorter than the second joint. Joints 2-12 longer than broad. Last funicular joint slightly longer than the sum of joints 10-11. Mandibles edentate and only with a pointed apical tooth. Palp formula 5,2.

Mesosoma robust. Pronotum and anterior third of mesonotum almost perpendicular to the posterior two thirds of the mesonotum. Posterior two thirds of mesonotum almost flat. Parapsidal furrows marked. Scutellum as high as the mesonotum; sides of the scutellum converging into a round posterior border. Basal and declivous propodeal faces slightly convex in side view. Basal face of the propodeum slightly declivous posteriorly. Declivous face of the propodeum flat. Area between basal and declivous faces of the propodeum gently concave and laterally subangulate. Declivous face of propodeum laterally superficially carinate. Metalloturn with a median lamellaceous tooth. Propodeal lobes round and lamellaceous. Propodeal spiracles small.

Petiole in side view sloping anteriorly in the two anterior fourths, subconvex in the third fourth and sloping in the posterior fourth. Sides of the petiole in dorsal view weakly convex. Anterior border of the petiole straight and laterally carinate. Subpetiolar process very small and subtriangular. Postpetiole anteriorly broader than the petiole; postpetiolar sides diverging posteriorly. Anterior border of the postpetiolar sternite with a superficial triangular "lip". Gastral tergite I in side view convex. Gastral sternite I large. Remaining gastral tergites and sternites slightly curved ventrally.

Legs as in the worker but more elongate. Hind basitarsi slightly shorter than hind tibiae.

Fore wings of our type 4, hind wings of our type 2 and 3 as defined in the description of the genus.

Sculpture. Head and mesosoma punctate, reticulorugose, the reticulation large on the mesonotum and larger than on mesonotum on the basal face of the propodeum and metapleurae. Petiole, postpetiole, gaster and legs smooth and with minute piligerous punctures slightly denser on the postpetiole. Body covered by hairs of three main types: (1) short, dense, suberect or subdecumbent, suberect, sparse and slightly shorter on the funicular joints; (2) longer than type (1), erect or subdecumbent, slightly longer on the gaster, absent on the antennae; (3) shorter than hair type (1), dense and decumbent on the funicular joints. In addition the funicular joints bear whitish, thick, appressed, sparse hairs, and the scapes with sparse hairs similar to type (2) but slightly shorter.

Colour. Dark brown-black with lighter mandibles, antennae and legs.

Measurements in mm and Indices: TL 2.52-3.19; HL 0.48-0.58; HW 0.50-0.58; EL 0.26-0.28; SL 0.23-0.28; WL 0.84-1.08; PeL 0.19-0.21; PeW 0.21-0.25; HFeL 0.48-0.62; HTiL 0.38-0.48; HBaL 0.32-0.46; LS4 0.32-0.44; LT4 0.58-0.72; CI 100.0- 104.2; SI 47.9-49.1; IGR 0.55-0.59.

Type Material

Baroni Urbani and de Andrade (2003):

Type locality: Honshu, Japan. Type material: 3 syntype workers labelled: "Japon, Oshima, Iya, Honshiu, 10.VI.28, Kisato, Proceratium japonicum Sant., Dr. Santschi F. 1937", in Naturhistorisches Museum Basel, examined.

Proceratium formosicola Type locality: Taiwan. Type material: 1 paratype worker labelled: 15.VIII.1980, Lushan (ca. 1000 m Alt.), Nantou Hsien, Taiwan, M. Terayama leg., Paratype, Proceratium formosicola, Terayama, 1985, in MTCS, examined.

References