Cephalotes chacmul

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Cephalotes chacmul
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Cephalotes
Species: C. chacmul
Binomial name
Cephalotes chacmul
Snelling, R.R., 1999

De Andrade 1999 Cephalotes OCR - Copy-615 Cephalotes-chacmul had.jpg

Nothing is known about the biology of Cephalotes chacmul.

Identification

A member of the texanus clade differing from its sister species, Cephalotes auriger, by the thin, appressed hairs on the first gastral tergite of the worker of auriger.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Mexico (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

The biology of many Cephalotes species is not known. Ants in this genus are common in the New World tropics and subtropics and are especially abundant and diverse in the canopies of Neotropical forests. The majority of species are arboreal. Species that live in other strata inhabit smaller trees, bushes or grass stems. These noon-arboreal species, due to their accessibility, are among the better studied members of the genus. There are also species that can be found in downed wood but it is likely the wood housed the colony before it fell to the ground. Soil nests are not known for any species nor do most species appear to extensively excavate plant tissue. They nest instead in preformed cavities. Overall, ants in the genus utilize a wide range of plants. Some species are predictable in their plant use but none appear to have evolved specialized mutualisms with particular plant species.

Worker castes typically include two forms, a worker and soldier, but there are a few species that are monomorphic. The larger soldier caste typically has an enlarged head disk. In some species the head of the soldier is very different from the worker while in others these differences are less pronounced. Queens and soldiers tend to share similar head morphology. Soldiers use their heads to plug the nest entrance. This can be very effective in excluding potential intruders. Other morphological differences between the worker castes are present but these differences have not been studied as well as head moprhology.

The behavioral repertoire of Cephalotes varians has been examined in great detail (ethograms from Wilson 1976, Cole 1980 and Cole 1983). Soldiers do little else besides defend the nest. This specialized soldier behavior is presumed to be the norm for most species. An especially interesting behavior occurs when workers are dislodged from trees: they "fly" towards the tree, often grabbing the trunk well above the ground (video).

Mature nest size varies, by species, from less than a hundred to many thousands of workers. Available evidence suggests most species are monogynous. Queens may mate with multiple males.

The proventriculus of the Cephalotes is peculiar relative to other ants. The morphology of the structure suggests it serves as a powerful pump and filter. This does not appear to lead these ants to have a highly specialized diet as most species appear to be general scavengers. Foragers have been observed feeding on carrion, bird feces, extrafloral nectaries and even tending membracids. Pollen feeding has been observed in some species, and this is somewhat specialized for ants, but it is not evident that any species restricts its diet to this resource in any significant way. Evidence for pollen feeding in Cephalotes has accumulated, in part, via finding digested pollen grains seen in infrabucal pellets. It has been suggested that the morphology of the proventriculus is a specialization for processing pollen.

More research examining all aspects of the biology of Cephalotes is needed. Our present understanding of these ants is largely based on species that live in locations other than the forest canopy, which is where Cephalotes are most common and diverse.

Castes

Nomenclature

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

  • chacmul. Cephalotes chacmul Snelling, R.R. in De Andrade & Baroni Urbani, 1999: 611, figs. 286, 287 (s.w.) MEXICO.

Description

Worker

Snelling (in de Andrade and Baroni Urbani 1999) – Measurements (mm): HW (greatest head width below the eyes) 0.84-0.89, HL (greatest length from the lower margin of the frontal lobes to the highest level of the margin of the vertex) 1.03-1.06, TL 3.4-4.0.

Head. About 1.2 times longer than broad. Lateral margins slightly divergent above, distinctly reflexed adjacent to eyes; dorsolaterad corners elevated and more or less crenulate; vertexal margin thin and cariniform, very weakly concave in frontal view. Front of head gently convex, with irregularly spaced fine foveolae and with fine, widely spaced longitudinal rugulae, especially across vertex and along sides. Gena and gulae area dull and with coarse longitudinal rugae. Foveae each with appressed, glittering scale-like seta; margins of head with short, erect, simple setae.

Mesosoma. Anterior margin of pronotal disc nearly straight; humeral angle distinct; side with three distinct spines, posterior spine shorter and with apex bluntly rounded or truncate. Mesoscutum with short, acute spine at side. Side of basal face of propodeum with three spines of variable length, mid spine sometimes bluntly rounded. Entire dorsum dull and with relatively coarse longitudinal rugae (partially replaced at sides by elongate setose foveae) that extend onto posterior slope of propodeum. Side of pronotum with curved longitudinal rugae on upper two-thirds or more; remainder of pronotal side irregularly roughened; mesepisternum and side of propodeum with much finer, irregular, longitudinal rugulae. Legs as in major.

Petiole with vertical anterior face, its summit cariniform and with two short submedian teeth; dorsal face with coarse, irregularly longitudinal setose foveae; lateral spines narrow and acute, slightly curved distad. Postpetiole disc with coarse elongate setose foveae; lateral spines similar to those of petiole but slightly broader and longer.

Metasomal tergum 1 invaginated at postpetiolar attachment and distinctly marginate anterolaterally, corner narrowly lamelliform. Disc of tergum 1 dull, weakly striate and with scattered setose foveae; sternum 1 dull, distinctly longitudinally striate at sides, middle one-third to one-half smooth and shiny.

Color blackish, appendages dark brownish; frontal lobes and mesosomal spines translucent yellowish; tibiae and tarsi reddish to yellowish; tergum 1 with anterolateral yellow spots.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 3.28-4.24; HL 0.84-0.96; HW 0.88-1.04; EL 0.24-0.28; PW 0.78-0.96; PeW 0.46-0.56; PpW 0.52-0.64; HBaL 0.30-0.35; HBaW 0.07-0.09; CI 104.7-108.3; PI 108.3-112.8; PPeI 169.5-171.4; PPpI 150.0; HBaI 23.3-25.7.

Soldier

Snelling (in de Andrade and Baroni Urbani 1999) – Measurements (mm): HW [greatest head width below the eyes] 1.48 (holotype), 1.48-1.55 (paratypes), HL (greatest length from the lower margin of the frontal lobes to the highest level of the margin of the vertex) 1.52 (holotype), 1.52-1.61 (paratypes), TL 5.2 (holotype), 4.9-5.4 (paratypes).

Head with complete frontal shield, about 1.05 (1.02-1.04) times as long as wide; margins of shield more strongly reflexed at sides, nearly straight across mid one-third of vertexal margin; dorsolateral corners of head thin and slightly reflexed, clearly visible in anterior view. Foveae of disc about 0.03-0.05 mm diameter, mostly separated by less than one-half fovea diameter, but with some interspaces greater than fovea diameter; interspaces slightly shiny and with numerous micropunctures, each fovea with one appressed, glittering scale-like seta that does not extend beyond fovea margin. Lateral margins of disc with sparse, short, erect, subspatulate setae; similar, but slightly longer, setae present along margins of posterolateral corners. Gular surface shiny between sparse foveae, each with glittering scale-like seta.

Mesosoma. Transverse pronotal carina distinct, somewhat irregular, broadly interrupted in middle; pronotal humerus absent; scapular angle acute; side of pronotal margin, in dorsal view, slightly sinuate and convergent distad, reentrant angle broadly rounded. Side of mesoscutum distinctly projecting as short, rounded lobe. Side of dorsal face of propodeum with short basal tooth; long, slightly curved blunt spine at mid length, and blunt posterior tooth. Dorsal face of propodeum short and abruptly rounded into posterior face.

Pronotum, anterior to transverse carina, slightly shiny between irregularly spaced foveae that become crowded laterad; remainder of pronotal dorsum and all of mesoscutum similar but foveae consistently denser; dorsum of propodeum dull, foveae deeper, contiguous and tending to be linearly arranged. All dorsal foveae with glittering scale-like, appressed setae. Side of pronotum with scattered foveae, mostly along posterior one-half, foveae smaller than those of dorsum and many without setae; mesepisternum dull, roughened, with scattered fine foveae and some irregular longitudinal rugulae. Side of propodeum dull, with irregular, widely spaced longitudinal rugulae; posterior face dull, without rugulae.

Procoxa, in lateral view, with large, robust conical process near base. Femora fusiform, without dorsal angulation.

Petiole with vertical anterior face; dorsal face shorter than anterior face, dull and roughened; lateral spines prominent, acute, and slightly curved caudad. Postpetiole strongly convex, dull and roughened, with setose foveae; lateral spines longer and thicker than those of petiole, acute and slightly curved caudad.

Gaster. Base of tergum 1 distinctly invaginated at postpetiolar attachment; distinctly marginate anterolaterally; disc dull and contiguously micropunctate and with sparse, shallow foveae, each with appressed glittering seta; basal one-third with weak, widely spaced longitudinal rugulae. Sternum 1 dull, contiguously micropunctate, and with some weak, longitudinal rugulae, especially at sides.

Dorsum of mesosoma and disc of metasomal tergum 1 with sparse, erect setae about 0.05 mm long; gastral segments also with longer marginal setae.

Color dull blackish; legs more brownish; cephalic shield translucent reddish-brown anterolaterally; gastral tergum 1 with large anterolateral yellowish spots.

de Andrade and Baroni Urbani (1999) - Measurements (in mm) and indices: TL 4.98-5.32; HL 1.28-1.40; HW 0.88-1.04; EL 0.28-0.32; PW 1.40-1.44; PeW 0.55-0.61; PpW 0.65-0.72; HBaL 0.32-0.36; HBaW 0.08-0.09; CI 108.6-109.4; PI 100.0-105.5; PPeI 229.5-254.5; PPpI 200.0-215.4; HBaI 22.2-25.0.

Type Material

Holotype soldier from Reserva Sian Ka'an, km 11, Sabana, (Quintana Roo, Mexico) 3-4 June 1986, A. Dejean, from pseudobulbs of Tillandsia balbiciana (Bromeliaceae) (Los Angeles County Museum of Natural History); paratypes four soldiers and nine workers, same data as the holotype, three paratypes deposited in Museum of Comparative Zoology, three in The Natural History Museum and the remaining nine in LACM.

Etymology

Chacmul is the name of the Mayan jaguar god used here as specific name in apposition.

References

  • de Andrade, M. L.; Baroni Urbani, C. 1999. Diversity and adaptation in the ant genus Cephalotes, past and present. Stuttgarter Beitrage zur Naturkunde Series B (Geolgie and Palaontologie). 271:1-889. (page 611, figs. 286, 287 soldier, worker described; description by Snelling)