Strumigenys cassicuspis

Strumigenys cassicuspis
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Myrmicinae
Tribe:	Attini
Genus:	Strumigenys
Species:	S. cassicuspis
Binomial name
Strumigenys cassicuspis (Bolton, 2000) Specimen Labels

Occurs in wet forest habitats, in leaf litter on the forest floor (Longino, Ants of Costa Rica).

Identification

Bolton (2000) - A member of the Strumigenys schulzi-group. Closely related to Strumigenys microthrix and Strumigenys stauroma, especially the latter species. Differences separating microthrix from both cassicuspis and stauroma are listed under microthrix; the other two are distinguished as follows.

S. cassicuspis: Posterior margin of clypeus without a transverse row of 4 erect hairs that are much longer and more conspicuous than the dense stubbly erect ground-pilosity that arises elsewhere on clypeus and on dorsal head behind clypeus. Occipital lobes in profile or in full-face view without numerous small peaks or tubercles from which short stubbly hairs arise. Dorsal surfaces of pronotum and mesonotum without suberect to erect short stubbly hairs.

S. stauroma: Posterior margin of clypeus with a transverse row of 4 erect hairs that are much longer and more conspicuous than the dense stubbly erect ground-pilosity that arises elsewhere on the clypeus and on dorsal head behind clypeus. Occipital lobes in profile or in full-face view with numerous small peaks or tubercles from which short stubbly hairs arise. Dorsal surfaces of pronotum and mesonotum with numerous suberect to erect short stubbly hairs present.

Longino (Ants of Costa Rica) - Mandibles in side view straight, not broadly curved ventrally; mandibles relatively short, subtriangular, much of the apical portion meeting along a serially toothed masticatory margin when closed (former Smithistruma); head relatively broad, CI 77-83; leading edge of the scape with entirely anteriorly directed short spatulate hairs; color red-brown; face punctate; disc of postpetiole reticulate-punctate; surface of face granular but not tuberculate; cephalic dorsum at level of frontal lobes without a transverse row of hairs that are much longer than the surrounding pilosity; face but not promesonotal dorsum covered with short, stiff, erect setae (stubble).

It is very similar to two other species: microthrix and stauroma. The former has no stubble. The latter has stubble, but also is covered with sharp low tubercles, giving the surface a very rough look.

Keys including this Species

• Key to Neotropical Strumigenys (as Pyramica)

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 16.4435376° to 9.266667°.

North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

• Source: AntMaps

Distribution based on Regional Taxon Lists

Neotropical Region: Belize, Colombia, Costa Rica (type locality), Guatemala, Honduras, Nicaragua.

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

Expand Explore Overview of Strumigenys biology  Strumigenys were once thought to be rare. The development and increased use of litter sampling methods has led to the discovery of a tremendous diversity of species. Many species are specialized predators (e.g. see Strumigenys membranifera and Strumigenys louisianae). Collembola (springtails) and other tiny soil arthropods are typically favored prey. Species with long linear mandibles employ trap-jaws to sieze their stalked prey (see Dacetine trap-jaws). Larvae feed directly on insect prey brought to them by workers. Trophallaxis is rarely practiced. Most species live in the soil, leaf litter, decaying wood or opportunistically move into inhabitable cavities on or under the soil. Colonies are small, typically less than 100 individuals but in some species many hundreds. Moist warm habitats and micro-habitats are preferred. A few better known tramp and otherwise widely ranging species tolerate drier conditions. Foraging is often in the leaf litter and humus. Workers of many species rarely venture above ground or into exposed, open areas. Individuals are typically small, slow moving and cryptic in coloration. When disturbed individuals freeze and remain motionless. Males are not known for a large majority of species. ‎

Nomenclature

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

• cassicuspis. Pyramica cassicuspis Bolton, 2000: 216, fig. 147 (w.) COSTA RICA. Combination in Strumigenys: Baroni Urbani & De Andrade, 2007: 117

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

Description

Worker

Holotype. TL 2.3, HL 0.64, HW 0.50, CI 78, ML 0.10, MI 16, SL 0.28, SI 56, PW 0.33, AL 0.62. Anterior clypeal margin transverse. Dentition as described in introduction to group. Occipital lobes strongly expanded laterally in full-face view. Scape markedly dorsoventrally flattened and broad in dorsal view. Freely projecting hairs on leading edge of scape spoon-shaped, at right-angles to long axis of scape or curved toward its apex; no hairs conspicuously curved toward the base of the scape. Apicoscrobal and pronotal humeral hairs absent. With head in full-face view lateral margins of occipital lobes with abundant short stubbly projecting erect hairs. Occipital lobes without minute peaks or tubercles. Dorsum of head without a transverse row of elongate standing hairs just behind highest point of vertex but clypeus and dorsum of head with short stubbly dense erect pilosity. Clypeus close to its posterior border without a transverse palisade-like row of much longer stouter hairs. Promesonotum in dorsal view flattened and very broad, without standing pilosity of any form. Femoral gland bullae elongate and conspicuous, especially on foreleg; bullae very obviously much longer than broad. Petiole in profile without trace of ventral spongiform tissue. Lateral spongiform lobes and posterior collar of petiole apparently absent, actually narrow and secondarily sclerotised, and pigmented so as to be virtually indistinguishable from the surrounding cuticle. With petiole in profile the dorsal length of the node distinctly greater than the height of its anterior face; in dorsal view the node conspicuously longer than broad. Spongiform strip at base of first gastral sternite vestigial to absent. Entirety of head and alitrunk reticulate-punctate. First gastral tergite with very short basigastral costulae, behind which the sclerite is glassy smooth.

Paratypes. TL 2.1-2.3, HL 0.60-0.66, HW 0.46-0.50, CI 76-78, ML 0.08-0.10, MI 13-16, SL 0.24-0.28, SI 52-56, PW 0.31-0.34, AL 0.60-0.64 (4 measured).

Type Material

Holotype worker, Costa Rica: Provo Alajuela, Rio Penas Blancas, 10°19'N, 84°43'W, 800 m., 26-28.iv.1987, wet forest, ex sifted leaf litter, #1579-s (J. Longino) (Instituto Nacional de Biodiversidad). Paratypes. 2 workers with same data as holotype; 2 workers Costa Rica: Provo Heredia, Est. Biol. La Selva, 10°26'N, 84°00'W, 50 m., 14.x.1991, wet forest, ex sifted leaf litter, #3078-s (J. Longino) (The Natural History Museum, Museum of Comparative Zoology, Los Angeles County Museum of Natural History).

References

• Baroni Urbani, C. & De Andrade, M.L. 2007. The ant tribe Dacetini: limits and constituent genera, with descriptions of new species. Annali del Museo Civico di Storia Naturale “G. Doria” 99:1-191.
• Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 216, fig. 147 worker described)
• Guerrero, R.J., Fernandez, F., Escarraga, M.E., Perez-Pedraza, L.F., Serna, F., Mackay, M.P., Sandoval, V., Vergara, V., Suarez, D., Garcia, E.I., Sanchez, A., Meneses, A.D., Tocora, M.C., Sosa-Calvo, J. 2018. New records of myrmicine ants (Hymenoptera: Formicidae) for Colombia. Revista Colombiana de Entomología 44: 238-259 (DOI 10.25100/socolen.v44i2.7115).

References based on Global Ant Biodiversity Informatics

• Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
• Branstetter M. G. and L. Sáenz. 2012. Las hormigas (Hymenoptera: Formicidae) de Guatemala. Pp. 221-268 in: Cano E. B. and J. C. Schuster. (eds.) 2012. Biodiversidad de Guatemala. Volumen 2. Guatemala: Universidad del Valle de Guatemala, iv + 328 pp
• Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
• Longino J. T. 2013. Ants of Honduras. Consulted on 18 Jan 2013. https://sites.google.com/site/longinollama/reports/ants-of-honduras
• Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
• Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.