Strumigenys madrigalae

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Strumigenys madrigalae
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. madrigalae
Binomial name
Strumigenys madrigalae
Lattke & Aguirre, 2015

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Lattke and Aguirre (2015) - The Reserva Madrigal (type locality) is a private reserve that neighbors Podocarpus National Park approximately 7 km SSE from Loja. It was previously a dairy farm and has been undergoing restoration towards forest during the last ten years. The specimens were taken from several samples along a 200 m long transect in mostly secondary vegetation, ranging from trees approximately 15 m high forming a loose canopy to more open bracken (Pteridium sp.) dominated understory with scattered trees and shrubs. Neighboring slopes to the sampling site across the stream bear dense forest with a canopy apparently not more than 15 m high. The area has an estimated average annual rainfall of 3000-2500 mm (Richter et al., 2013).

Identification

Lattke and Aguirre (2015) - Mandibular dentition with 5 acute teeth apicad of basal lamella, the basal 3 largest; teeth followed by 4 minute preapical denticles, and apical tooth; no diastemma between teeth and lamella, lamella higher than longest teeth. Postpetiolar dorsum smooth.

This species fits within the schulzi group as defined by Bolton (2000:214) but the dental arrangement in S. madrigalae is unlike any of the other species in the group as it lacks a couple of teeth after the first five that follow the basal lamella, for a total of 10 teeth compared with the 12 teeth of other species. Using the [[Key to Neotropical Strumigenys (as Pyramica)|key for Neotropical Pyramica} in Bolton (2000:137), this species will key smoothly to couplet 65, where it coincides with the characteristics of Strumigenys microthrix, a species known from Costa Rica and Colombia. Using the original description of S. microthrix by Kempf (1975:422) as well as that of Bolton (2000: 185), and images of a specimen (INBIOCRI001283688) available from Antweb, it was possible to identify several discrete differences between the two species. The occipital lobes in S. microthrix are more strongly expanded and its mandible has only 5 acute teeth between the minute preapical denticles and the basal lamella. The hairs laterally bordering the clypeus are more slender in S. madrigalae. S. microthrix lacks standing hairs on the mesosomal and petiolar dorsum, and the anterior margin of its petiolar node forms an abrupt angle with peduncle. The postpetiole has a negligible amount of ventral spongiform tissue. The postpetiolar node has one pair of erect hairs and very sparse erect hairs on the gastral dorsum. The postpetiolar dorsum is densely sculpted in S. microthrix.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Ecuador (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Castes

Nomenclature

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

  • madrigalae. Strumigenys madrigalae Lattke & Aguirre, 2015: 178, figs. 4-5 (w.) ECUADOR.

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 0.61, HW 0.45, ML 0.13, SL 0.31, PW 0.29, AL 0.61mm; CI 74, MI 21, SI 69. Posterior cephalic margin has shallow median concavity with head in dorsal view, occipital lobe weakly expanded laterally; posterolateral cephalic margin convex, with curved decumbent spatulate hairs, apical scrobal hair absent. Four standing hairs present between highest point of vertex and occipital margin. Eye oval-elongate with 5 ommatida in the longest axis. Scape external margin with appressed spatulate hair close to base; also with three erect spatulate hairs, one basad of basal angle; three spatulate hairs that curve apicad present close to scape apex. Anterolateral clypeal margins convex throughout, clypeal dorsum with appressed squamate hairs. Mandibular dentition with 5 acute teeth apicad of basal lamella, the basal 3 are largest; followed by 4 minute preapical denticles, and apical tooth; no diastemma between teeth and lamella, lamella higher than longest teeth.

Promesonotal dorsal margin broadly convex in lateral view, metanotal groove broad and shallow, propodeal dorsal margin straight, slightly elevated above metanotal groove and forming obtuse angle with declivitous margin. Pronotal humeral hair absent, mesonotum with two hairs, erect and slightly arched medially. Anterior pronotal margin with transverse crest bearing row of short spatulate hairs. Propodeal tooth short, sharply pointed with lamella extending posterad towards low metapleural lobes; propodeal spiracle directed posterolateally, separated from posterior margin of lamella by not more than one diameter.

Petiolar node forms convex dome with two erect hairs close to posterior margin, hairs slightly inclined posterad, anterolaterally with two pairs of curved decumbent hairs; postpetiole with three pairs of standing hairs; anterad, posterad, and laterad. Petiole with narrow fringe of spongiform tissue along posterior margin, laterally and dorsally, none ventrally; postpetiole with well-developed ventral and lateral spongiform tissue which continues onto dorsoposterior margin, narrow fringe present on anterior margin of abdominal tergite IV; none present on abdominal sternite IV. Abdominal tergite IV with sparse erect hairs, each slightly inclined posterad; mostly smooth and shining with short, basal longitudinal costulae, not longer than the maximum metatibial width. Profemur dorsum with elongate bullae, rice grain shaped. Outer surface of meso-and metatibia with decumbent arched hairs, each hair about as long as respective maximum tibial width or slightly shorter. Head, mesosoma, and petiole densely and finely reticulate-punctae; mesopleuron mostly smooth medially; postpetiolar dorsum smooth. Coxae, femora and tibiae densely reticulate-punctate. Body mostly ferruginous brown, dorsum of head and thorax dark brown, gaster black.

Queen

HL 0.71, HW 0.51, ML 0.15, SL 0.34, PW 0.41, AL 0.82mm; CI 72, MI 21, SI 67. Gyne comparable with the worker and differing in expected traits such as the greater development of the mesosoma and presence of ocelli.

Type Material

Holotype: Ecuador, Loja, Reserva El Madrigal, 4.04655°S 79.17583°W, 6.3 km SSE of Loja, 2350m, 28 August 2014, J. Lattke 3590-17. Holotype (worker) deposited in Museo de Zoologia. Paratype: One dealate queen with the same locality data and date as the holotype but from sample Lattke 3590-14 is also deposited in QCAZ.

Etymology

The specific epithet “madrigalae” is derived from the name of the nature reserve in which the specimens were found, Madrigal.

References