Sericomyrmex radioheadi

Sericomyrmex radioheadi
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Sericomyrmex
Species:	S. radioheadi
Binomial name
	Sericomyrmex radioheadi; Ješovnik & Schultz, 2017

Known only from the type collection. No biological details of the species are known. General details about the biology of the genus are given here.

Identification

Ješovnik & Schultz (2017) - Medium-sized species; mandible dorsally smooth; frontal lobe triangular, narrow, directed anterad; antenna long, antennal scape reaching posterior cephalic corner; posterior cephalic emargination deep; lateral mesonotal tubercles sharp and long; first gastral tergite with lateral carinae distinct, dorsal carinae faint or absent.

The body color of S. radioheadi is evenly light yellow, lighter than in other Sericomyrmex species. Only dried, pinned specimens were available for this species, however, so the pale color may be due to age. Morphology indicates that S. radioheadi is the sister species to Sericomyrmex bondari, with which it shares a similar head shape, smooth mandibles, and sharp mesonotal tubercles. S. bondari can be separated from radioheadi by its larger body size, shorter scape, and shorter and blunter lateral mesonotal tubercles, and by the presence of at least some thick black hairs.

Keys including this Species

Key to Sericomyrmex

Distribution

Known from an Amazonian Venezuela type collection.

Latitudinal Distribution Pattern

Latitudinal Range: 2.0164° to 2.0164°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Neotropical Region: Venezuela (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

Explore Fungus Growing

For additional details see Fungus growing ants.

A handful of ant species (approx. 275 out of the known 15,000 species) have developed the ability to cultivate fungus within their nests. In most species the fungus is used as the sole food source for the larvae and is an important resource for the adults as well. Additionally, in a limited number of cases, the fungus is used to construct part of the nest structure but is not as a food source.

These fungus-feeding species are limited to North and South America, extending from the pine barrens of New Jersey, United States, in the north (Trachymyrmex septentrionalis) to the cold deserts in Argentina in the south (several species of Acromyrmex). Species that use fungi in nest construction are known from Europe and Africa (a few species in the genera Crematogaster, Lasius).

The details of fungal cultivation are rich and complex. First, a wide variety of materials are used as substrate for fungus cultivating. The so-called lower genera include species that prefer dead vegetation, seeds, flowers, fruits, insect corpses, and feces, which are collected in the vicinity of their nests. The higher genera include non leaf-cutting species that collect mostly fallen leaflets, fruit, and flowers, as well as the leafcutters that collect fresh leaves from shrubs and trees. Second, while the majority of fungi that are farmed by fungus-feeding ants belong to the family Lepiotaceae, mostly the genera Leucoagaricus and Leucocoprinus, other fungi are also involved. Some species utilise fungi in the family Tricholomataceae while a few others cultivate yeast. The fungi used by the higher genera no longer produce spores. Their fungi produce nutritious and swollen hyphal tips (gongylidia) that grow in bundles called staphylae, to specifically feed the ants. Finally, colony size varies tremendously among these ants. Lower taxa mostly live in inconspicuous nests with 100–1000 individuals and relatively small fungus gardens. Higher taxa, in contrast, live in colonies made of 5–10 million ants that live and work within hundreds of interconnected fungus-bearing chambers in huge subterranean nests. Some colonies are so large, they can be seen from satellite photos, measuring up to 600 m3.

Based on these habits, and taking phylogenetic information into consideration, these ants can be divided into six biologically distinct agricultural systems (with a list of genera involved in each category):

Nest Construction

A limited number of species that use fungi in the construction of their nests.

some Crematogaster
some Lasius

Lower Agriculture

Practiced by species in the majority of fungus-feeding genera, including those thought to retain more primitive features, which cultivate a wide range of fungal species in the tribe Leucocoprineae.

Coral Fungus Agriculture

Practiced by species in the Apterostigma pilosum species-group, which cultivate fungi within the Pterulaceae.

some Apterostigma

Yeast Agriculture

Practiced by species within the Cyphomyrmex rimosus species-group, which cultivate a distinct clade of leucocoprineaceous fungi derived from the lower attine fungi.

some Cyphomyrmex

Generalized Higher Agriculture

Practiced by species in several genera of non-leaf-cutting "higher attine" ants, which cultivate a distinct clade of leucocoprineaceous fungi separately derived from the lower attine fungi.

Leaf-Cutter Agriculture

A subdivision of higher attine agriculture practiced by species within several ecologically dominant genera, which cultivate a single highly derived species of higher attine fungus.

Note that the farming habits of Mycetagroicus (4 species) are unknown. Also, while species of Pseudoatta (2 species) are closely related to the fungus-feeding genus Acromyrmex, they are social parasites, living in the nests of their hosts and are not actively involved in fungus growing. ‎

Worker

Worker (USNMENT00924059), frontodorsal view of mesonotal tubercles.

Figure 52.

Jesovnik and Schultz 2017. Figure 52. S. radioheadi worker (USNMENT00924061), SEM images. a Head, full-face view b mandibles c eye d mesosoma and metasoma, lateral view e mesosoma(detail), lateral view f propodeum and metasoma, anterolateral view.

Castes

Nomenclature

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

radioheadi. Sericomyrmex radioheadi Ješovnik & Schultz, 2017a: 86, figs. 51, 52 (w.) VENEZUELA.
- Type-material: holotype worker, 8 paratype workers.
- Type-locality: holotype Venezuela: Amazonas, 10 km. N San Carlos de Río Negro, vii.-viii.1978 (K. Clark); paratypes with same data.
- Type-depositories: MCZC (holotype); CASC, MZSP, USNM (paratypes).
- Distribution: Venezuela.

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

Description

Worker

(holotype): HWe 1–1.08 (1.02) HW 1–1.08 (1.04) HW1 0.93–1 (1) HW2 1.08–1.15 (1.1) HW3 0.64–0.73 (0.72) IFW1 0.61–0.66 (0.62) IFW2 0.24–0.27 (0.24) HL1 1–1.08 (1) HL2 0.84–0.9 (0.88) SL 0.75–0.84 (0.8) EL 0.15–0.18 (0.15) Om 9–12 (9) WL 1.35–1.43 (1.36) PL 0.24–0.34 (0.29) PPL 0.2–0.25 (0.25) GL 0.92–1.02 (0.93) HFL 1.18–1.3 (1.25) PW 0.64–0.75 (0.65) CI 98–103 (102) FLI 59–62 (61) SI 75–82 (78) OI 15–18 (15) CEI 12–17 (12) [N=9]

Pilosity. Pubescence dense, appressed to decumbent, light yellow. Hairs curved, darker in color at base, yellow to gray, appressed to suberect, mostly decumbent.

Head. In full-face view evenly broad and long (CI=101 ± 2), posterior corner acute, posterior cephalic emargination deep (CEI=14 ± 2), gradually impressed. Vertexal impression distinct, frontal tumuli barely visible. Mandible with 7–8 teeth, dorsally smooth and glossy, finely transversely striate only along masticatory margin, striation sometimes faint. Eye medium-sized (OI =16 ± 1), mildly convex, without white layer, 9–12 ommatidia across largest diameter. Frontal lobe triangular, narrow (FLI=61 ± 1), posterior margin shorter than medial, lateral margin long, sometimes mildly convex. Frontal carina straight to slightly curved laterally, complete, reaching posterior cephalic corner. Antennal scape long (SI=77 ± 2), reaching posterior cephalic corners.

Mesosoma. Lateral pronotal tubercles short, lateral mesonotal tubercles sharp and long (Figure 51d, 52e); posterior mesonotal tubercles low and obtuse. Propodeal carinae faint, with distinct posterodorsal denticles.

Metasoma. Petiole with two low dorsal denticles; postpetiole with four low, short carina, two dorsal and two lateral, lateral pair faint. First gastral tergite with lateral carinae distinct, dorsal carinae absent or faint.

Type Material

Holotype worker: Venezuela, Amazonas, 10 km N of San Carlos de Río Negro, [2.0164, -67.0599] Jul-Aug 1978, K. Clark (Museum of Comparative Zoology: 1w, USNMENT00924059). Paratypes: same data as holotype (National Museum of Natural History: 2 w: USNMENT00924060; 2w, USNMENT00924063) (California Academy of Sciences: 2w, USNMENT00924061) (Museu de Zoologia da Universidade de Sao Paulo: 2w, USNMENT00924062).

Etymology

This species is named after the English rock band Radiohead as an acknowledgement of their longstanding efforts in environmental activism, especially in raising climate-change awareness, and in honor of their music, which is an excellent companion during long hours at the microscope while conducting taxonomic revisions of ants. The species name is a masculine noun in the genitive case.

References

Ješovnik, A., Schultz, T.R. 2017. Revision of the fungus-farming ant genus Sericomyrmex Mayr (Hymenoptera, Formicidae, Myrmicinae). ZooKeys, 670, 1–109 (DOI 10.3897/zookeys.670.11839).