Myrmecina ryukyuensis

Myrmecina ryukyuensis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Crematogastrini
Genus:	Myrmecina
Species:	M. ryukyuensis
Binomial name
Myrmecina ryukyuensis Terayama, 1996

Common Name
Kogata-kadofushi-ari
Language:	Japanese

Myrmecina ryukyuensis is found on the floor of broadleaf forests where it nests under stones (Japanese Ant Image Database).

Identification

Terayama (1996) - Similar to Myrmecina sauteri from Taiwan. However it is easily distinguished from the latter by the straight anterior margin and rounded anterolateral corners of first gastral tergite in dorsal view (concave anterior margin and acutely produced anterolateral corners in the sauteri type specimen).

Distribution

Distribution based on Regional Taxon Lists

Palaearctic Region: Japan (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

• ryukyuensis. Myrmecina ryukyuensis Terayama, 1996: 29, figs. 69-71 (w.) JAPAN.

Taxonomic Notes

Although the species is distributed in the Nansei Islands, specimens from the Sakishima Group are slightly different from those collected on Amai-oshima I. and Okinawa I., in having smaller body size, less intense sculpturation, and smaller eyes. These differences need to be assessed as to whether they indicate infraspecific variation or the presence of several species (Japanese Ant Image Database).

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

Description

Worker

Holotype. HL 0.60 mm; HW 0.59 mm; SL 0.40 mm; CI 98; SI 78; WL 0.65 mm; PL 0.18 mm; PH 0.20 mm; DPW0.18 mm; TL2.4mm.

Head almost as long as wide, with shallowly concave posterior margin in frontal view; frons rnicroreticulate with reticulate rugae; genae microreticulate. Mandibles with acute apical and preapical teeth following 6 small blunt teeth. Anterior margin of clypeus with a small median lobe and a pair of lateral angles. Antennae with 12 segments; scape microreticulate, 0.75x head length. Eyes small, smaller than the 10th antennal segment, and each consisting of 6 facets.

Dorsum of alitrunk weakly rnicroreticulate, with relatively irregular longitudinal rugae; lateral faces of pronotum with 6 rugae; anterolateral corners of propodeum with small blunt teeth; propodeal teeth slightly longer than its basal width. Petiole wider than long in lateral view; disc slightly wider than long in dorsal view. Subpetiolar process low, anteroventoral corner acutely produced. Postpetiole 1.2x as wide as long in dorsal view.

Gaster very weakly rnicroreticulate and subopaque; anterior border of 1st gastral tergite straight, anterolateral borders rounded in dorsal view.

Body blackish brown; mandibles, antennae, legs and tip of gaster yellowish brown.

Variation. The specimens from the Sakishima Is. Are distinguished from the type series (Okinawa and Amarni materials) by the smaller size (HL 0.52-0.55 mm, HW 0.52-0.55 mm), lighter coloration of body, and weaker and more irregular rugae on head and dorsum of alitrunk in worker. The differences of body size are more distinct in females; HL 0.68 mm and HW 0.70 mm in Okinawa material, while HL 0.58 mm and HW 0.60 mm in Sakishima material. However, I regard these morphological differences as a geographic variation within a single species. Much information will be needed to finally determine the exact taxonomical status of those populations.

Type Material

Holotype. Worker, Shuri, Okinawa-jima, Okinawa Pref., 6.X.1988, M. Terayarna leg. Paratypes. 1 worker, same data as holotype; 1 female, 1 worker, Chibana, Okinawa-jima, Okinawa Pref., 29.XII.1989, M. Terayama leg.; 1 worker, same locality, 20.V.1982, H. Takamine leg.; 1 worker, Okinawa-jima, Okinawa Pref., 30.III.1983, H. Takantine leg.; 2 workers, Sumiyo-son, Amami-oshima, Kagoshima Pref., 21.III.1980, M. Terayama leg.

References

• Imai, H.T., Kihara, A., Kondoh, M., Kubota, M., Kuribayashi, S., Ogata, K., Onoyama, K., Taylor, R.W., Terayama, M., Yoshimura, M., Ugawa, Y. 2003. Ants of Japan. 224 pp, Gakken, Japan.
• Terayama, M. 1996b. Taxonomic studies on the Japanese Formicidae, part 2. Seven genera of Ponerinae, Cerapachyinae and Myrmicinae. Nature and Human Activities. 1:9-32. (page 29, figs. 69-71 worker described)

References based on Global Ant Biodiversity Informatics

• Shimono A., and S. Yamane. 2003. Ant species diversity on Okinoerabu-jima, the Ryukyus, southern Japan. For the Establishment of Remote Islands Study (Kagoshima Univ.) 3: 11-29.
• Terayama M. 1996. Taxonomic studies on the Japanese Formicidae, part 2. Seven genera of Ponerinae, Cerapachyinae and Myrmicinae. Nature & Human Activities 1: 9-32.
• Terayama M., S. Kubota, and K. Eguchi. 2014. Encyclopedia of Japanese ants. Asakura Shoten: Tokyo, 278 pp.
• Yamane S. 2016. How many species of Ants in Amami Islands? (in Japanese). Part 2, chapter 1 in How many species of Ants in Amami Islands? Pp. 92-132.
• Yamane S., S. Ikudome, and M. Terayama. 1999. Identification guide to the Aculeata of the Nansei Islands, Japan. Sapporo: Hokkaido University Press, xii + 831 pp. pp, 138-317.
• Yamane S.; Ikudome, S.; Terayama, M. 1999. Identification guide to the Aculeata of the Nansei Islands, Japan. Sapporo: Hokkaido University Press, xii + 831 pp. pp138-317.