Probolomyrmex lamellatus, Oliveira & Feitosa, 2019

Oliveira, Aline M. & Feitosa, Rodrigo M., 2019, Taxonomic revision of the genus Probolomyrmex Mayr, 1901 (Hymenoptera: Formicidae: Proceratiinae) for the Neotropical Region, Zootaxa 4614 (1), pp. 61-94 : 86-88

Probolomyrmex lamellatus New species

( Figs. 24 , 25 )

Holotype: BRAZIL: Pará: Terra Santa, FLONA, Saracá-Taquera, Base Patauá , 1°51’27.23”S 56°27’48.4”W, 70m, 25–29.viii.2016, R.M. Feitosa, E.Z. Albuquerque, R. Silva col, Winkler (worker) [ DZUP, unique specimen identifier DZUP 549767 ].

Diagnosis: Propodeum and petiole entirely emarginated posteriorly by a conspicuous lamella, without teeth. Postero-ventral lobe of petiole short and subquadrate. Subpetiolar process weakly developed. Prora weekly developed and dorsal protuberance on the posterior region of the first gastral tergite weakly developed.

Worker measurements: (n=1) HL 0.50; HW 0.30; SL 0.30; WL 0.59; PL 0.30; PW 0.24; PH 0.20; TL 2.11; CI 59.3; SI 59.3; PI 78.5.

Worker description: Frontoclypeal shelflike projection micropunctate; mandibles foveated; external surface of mandibular basal margin large and imbricated ( Fig. 24B – esm). Antennal funiculi with pits; tip of apical segment of antennae bearing different sized pits ( Fig. 24C – Ap). Mesopleuron foveate and micropunctate; metapleuron alveolate and foveated; lateral faces of propodeum foveated and micropunctate; alveoli denser just above metapleural gland orifice; opening of metapleural gland large, with smooth anterior region, surrounded by rows of hairs ( Fig. 24D ). Petiolar node and postero-ventral lobe of petiole with incomplete foveae and micropunctures; latero-ventral region of petiole and subpetiolar process alveolate ( Fig. 24E ). Posterior region of second gastral tergite with transversal rows of deep rounded pits.

Space between mesosomal foveae covered by dense pubescence.

Head 1.8 times longer than wide ( Fig. 25B ). Hypostomal margin curved ( Fig. 24B – he). Antennal scapes extend to head midlength, distance from scape apex to of head more than two times pedicel length (SI 59.3). Propodeum and petiole entirely emarginated posteriorly by a dark lamella, without teeth ( Fig. 25A ); Petiole 1.5 times longer than high (PI 78.5) posterior face short, straight, and smooth; postero-ventral lobe short and subquadrate; subpetiolar process weakly developed ( Fig. 24E ). First gastral segment with weakly developed prora and dorsal protuberance on posterior region of tergite weakly developed ( Figs. 24A , 25A ).

Etymology: The epithet refers to the posterior lamella of the propodeum and petiole, an exclusive characteristic of this species.

Distribution ( Fig. 29 ): Brazil (PA).

Comments: Probolomyrmex lamellatus is similar to P. cegua , but the head is comparatively longer, the propodeum and petiole are unarmed and completely emarginated by a dark lamella, and the postero-ventral lobe of petiole is subquadrate. The single known specimen came from a leaf-litter sample collected at in mature lowland Amazon forest.

Figures

FIGURE 24. SEM micrography of Probolomyrmex lamellatus sp. n. (holotype worker). A. Habitus. B. Mandibles (he = hypostomal margin; esm = external surface of basal region of mandible). C. Antenna (ap = antennal pit; lah = long appressed hair; sh = short hair). D. Metapleural gland. E. Petiole (pil = postero-inferior lobe of petiole; sp = subpetiolar process).

FIGURE 25. Probolomyrmex lamellatus sp. n. (holotype worker). A. Habitus. B. head in frontal view. C. dorsal view.

FIGURE 29. Distribution map for the Neotropical species of Probolomyrmex.