Strumigenys madrigalae, Lattke & Aguirre, 2015

Lattke, John E. & Aguirre, Nikolay, 2015, Two New Strumigenys F. Smith (Hymenoptera: Formicidae: Myrmicinae) from Montane Forests of Ecuador, Sociobiology 62 (2), pp. 175-180 : 178-179

Strumigenys madrigalae n. sp.

Figs 4 – 5. Strumigenys madrigalae n. sp. Worker. Scale bar

= 0.25mm. Pilosity omited.

Fig 4. Strumigenys madrigalae n. sp., head dorsal view.

Fig 5. Strumigenys madrigalae n. sp., body lateral view. Elongated shape on mesopleuron outlined by broken line defines area of smooth and shining sculpturing.

Diagnosis. 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.

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 QCAZ . 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.

Worker description. 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

Sociobiology 62(2): 175-180 (June, 2015) 179

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 reticulatepunctae; mesopleuron mostly smooth medially; postpetiolar dorsum smooth. Coxae, femora and tibiae densely reticulatepunctate. Body mostly ferruginous brown, dorsum of head and thorax dark brown, gaster black.

Gyne. 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.

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

Discussion. 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 for Neotropical Pyramica in Bolton (2000:137), this species will key smoothly to couplet 65, where it coincides with the characteristics of S. 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 . Please see the discussion for S. lojanensis for information on the type locality of S. madrigalae .