Myrmica titanica

Myrmica titanica
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Myrmicini
Genus:	Myrmica
Species:	M. titanica
Binomial name
	Myrmica titanica; Radchenko & Elmes, 2001

Almost all specimens have been collected foraging on the ground or on fallen trees in well-developed forest. K. Eguchi (pers. comm.) collected workers emerging from a natural cavity in a tree cut down for timber; unfortunately, he had no tools to cut into the wood to "excavate" the colony. This led us to suppose that M. titanica might be a truly arboreal species living and foraging mainly in the canopy, in which case it might be endangered by excessive logging activities. Specimens were found at altitudes 2000-2200 m.

Identification

Radchenko and Elmes (2010) – A member of the ritae complex of the ritae species group. Except for Myrmica angulata, it differs from all other species of the ritae-complex by the punctated surfaces between the rugae of the petiole and postpetiole. In addition, it is the largest Myrmica species in the World so far discovered, having HW > 1.80 mm, HL > 2.10 mm and AL > 3.30 mm (for details see Radchenko and Elmes 2001a; Radchenko, Elmes and Viet 2006).

Keys including this Species

Distribution

Northern Vietnam.

Distribution based on Regional Taxon Lists

Oriental Region: Vietnam (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.

Biology

Castes

Known only from the worker caste.

Nomenclature

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

titanica. Myrmica titanica Radchenko & Elmes, 2001b: 222, figs. 1-7 (w.) VIETNAM. See also: Radchenko & Elmes, 2010: 306.

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

Description

Worker

Extremely large ants, currently the largest known Myrmica species.

Head longer than wide, with slightly convex sides and occipital margin, occipital corners broadly rounded and upper latero-ventral corners pointed; anterior clypeal margin shallowly but distinctly notched medially; mandibles with 7-8 teeth. Frontal carinae feebly curved, frons wide; antenna! sockets surrounded by a single ruga. Antennal scape long (about the same length as head), gradually and weakly curved at the base.

Alitrunk long and low, with very weakly convex promesonotal dorsum, promesonotal suture visible from above, metanotal groove distinct and deep: metapleural lobes project apically to form sharp teeth. Propodeal spines very long, acute (in the holotype, they converge somewhat from their midlength but in the paratype specimen they are more or less straight, and slightly divergent. Petiole long and narrow; its node slightly longer than peduncle. anterior surface very feebly concave and dorsal surface feebly convex, sloping gradually downwards (seen in profile); postpetiole fig-shaped (from above), slightly longer than high, its anterior surface feebly convex with rounded node dorsum (in profile). Spurs on middle and hind tibiae well developed, distinctly pectinate.

Whole body with very coarse sculpture. Frons between frontal carinae levels with the eyes, with five to seven sinuous rugae. Only frons and genae with sinuous rugae, other part of head dorsum with coarse reticulation. Clypeus with coarse longitudinal rugae; mandibles coarsely striato-rugulose; frontal triangle smooth and shiny.

Alitrunk dorsum, petiole and post petiole very coarsely reticulate; sides of pronotum with reticulation, mesopleurae and sides of propodeum with rugae. Surfaces between rugae of head and alitrunk not punctured, appearing smooth and shiny; petiole and postpetiole finely but distinctly punctured. Gaster smooth and shiny. Abundant long, outstanding hairs on head margins and alitrunk, extremely long hairs on promesonotal dorsum; very abundant, long erect hairs on antennal scapes and tibiae. Colour of alitrunk and head dark reddish-brown, gaster and appendages reddish-brown.

Type Material

Holotype, w, Northern Vietnam, Lao Cai, Sa Pa, Fan Sipan, all. 2020 m, April 1998, leg. B. T. Viet (Kagoshima); para type, 1 w with the same label, probably from the same nest (Elmes)

Etymology

Radchenko and Elmes (2010) - from the word titanic = colossal or gigantic derived from the Titans, the "Older Gods" of Ancient Greece, used here to describe the extraordinary size of this species compared to other Myrmica.

References

Liu, C., Fischer, G., Hita Garcia, F., Yamane, S., Liu, Q., Peng, Y.Q., Economo, E.P., Guénard, B., Pierce, N.E. 2020. Ants of the Hengduan Mountains: a new altitudinal survey and updated checklist for Yunnan Province highlight an understudied insect biodiversity hotspot. ZooKeys 978, 1–171 (doi:10.3897/zookeys.978.55767).
Radchenko, A.G. & Elmes, G.W. 2010. Myrmica ants of the Old World. Fauna Mundi 3: 1-789.
Radchenko, A.G. ; Elmes, G .W. 2001b. First record of the genus Myrmica (Hymentoptera: Formicidae) from northern Vietnam, with a description of two new species. Annales Zoologici (Warsaw) 51(2): 221-225. (page 222, Figs. 1-7 worker described)
Radchenko, A.G., Elmes, G.W. & Bui, T.V. 2006. Ants of the genus Myrmica from Vietnam, with a description of a new species. Myrmecologische Nachrichten 8: 35-44.

References based on Global Ant Biodiversity Informatics

Fontanilla A. M., A. Nakamura, Z. Xu, M. Cao, R. L. Kitching, Y. Tang, and C. J. Burwell. 2019. Taxonomic and functional ant diversity along tropical, subtropical, and subalpine elevational transects in southwest China. Insects 10, 128; doi:10.3390/insects10050128
Ogata K. 2005. Asian ant inventory and international networks. Report on Insect inventory Project in Tropic Asia TAIIV: 145-170.
Radchenko A.G., G.W. Elmes, and B.T. Viet. 2006. Ants of the genus Myrmica (Hymenoptera: Formicidae) from Vietnam, with a description of a new species. Myrmecologische Nachrichten 8: 35-44.