Myrmicocrypta bucki

Type material was collected from a nest found in forest habitat.

Identification
Sosa-Calvo & Schultz (2010) - Similar in size and habitus to Myrmicocrypta erectapilosa, but differing from it by having frontal lobes vestigial, failing to cover antennal insertions; hypostomal teeth long; vertexal carina present; humeral and lateral pronotal spines acute; dorsum of pronotum smooth and glabrous; propodeal spines long and acute; petiole subquadrate.

M. bucki more specifically differs from M. erectapilosa by having simple, curved hairs (simple but entirely erect in M. erectapilosa); frontoclypeal teeth blunt (large and acute in M. erectapilosa); hypostomal teeth long (short and triangular in M. erectapilosa); frontal lobes narrow (triangular in M. erectapilosa) exposing part of the antennal condyles; vertexal carinae forming a pair of tubercles on cephalic margin in full-face view (these tubercles absent in M. erectapilosa); humeral and lateral tubercles acute (reduced in M. erectapilosa); node of petiole subquadrate in profile (rounded in M. erectapilosa). M. bucki can be separated from any other Myrmicocrypta species by the presence of simple, semierect hairs.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Peru.

Castes
Known only from the worker caste.

Nomenclature

 *  bucki. Myrmicocrypta bucki Sosa-Calvo & Schultz, 2010: 192, figs. 23-26 (w.) PERU.

Worker
TL = 3.56 (3.28-3.65); WL = 0.97 (0.91-1.01); HL = 0.75 (0.72-0.77); HW = 0.64 (0.62-0.67); SL = 0.69 (0.66-0.72); ML = 0.51 (0.45-0.54); EL = 0.07 (0.05-0.07); PL = 0.35 (0.31-0.35); PPL = 0.17 (0.16-0.19); GL = 0.81 (0.72-0.83); CI = 85 (86-88); SI = 108 (101-109); MI = 68 (63-71); FLD = 0.13 (0.11-0.14) (n = 9).

Head. Head almost 1.2X longer than broad; posterior margin convex, convexity interrupted by two carinate tubercles in vertexal area; integument matte and strongly rugole-reticulate; frontal carinae obsolete or vestigial; eye very small with seven to nine ommatidia in total; eyes above middle of head; antennal scape reticulate and long, surpassing cephalic corners by twice its apical width; clypeal apron convex and medially slightly angulate, hyaline, and transversely weakly striate; clypeal pilosity originating near posterior margin of apron and extending over mandibles, consisting of five to six pairs of lateral hairs and of one median unpaired seta, much thicker and 3x as long (length holotype = 0.15, paratypes = 0.13-0.15 mm) as lateral hairs; clypeus with a pair of blunt frontoclypeal teeth covered with simple, curved hairs; mandibles with six to seven teeth decreasing in size from apex to base; dorsal surface of mandibles striolate; frontal lobes strongly reduced, exposing antennal condyles in full-face view; hypostomal teeth long; occipital “collar” (neck) reduced to two low, blunt tubercles; antennal scape wider near its apex than at rest of its length; anterior edge of antennal scape minutely denticulate; in full-face view anterior and posterior edges of antennal scape bearing suberect to erect hairs; hairs on ventral portion of head narrowly spatulate. Mesosoma: Integument of mesosoma minutely puncate. Dorsum of pronotum smooth and glabrous with low humeral tubercles; lateral spines acute and dentiform, longer and more discrete than other mesosomal tubercles; lacking anterior pronotal tubercles or spines; inferior corner of pronotum evenly rounded; propleuron adjacent to inferior pronotal edge with a broadly obtuse angle and with some subdecumbent or suberect, simple or extremely narrowly spatulate hairs; mesonotum with lateral tubercles reduced to carinae, anterior tubercles low; mesonotal groove smooth and glabrous; median mesonotal tubercles low; posterior mesonotal tubercles blunt apically and slightly longer than or similar in size to median tubercles; metanotal groove with a single median longitudinal carina that extends from posterior portion of mesonotum through anterior portion of propodeum; propodeum anteriorly carinate, lacking anterior spines or tubercles; posterior propodeal spines long and acute; dorsum and declivous of propodeum with lateral carinae extending to propodeal lobes; base of propodeum flat, in profile subequal to declivity of propodeum. Metasoma: Petiole pedunculate; node of petiole, in proÞle, with two small anterior tubercles and two larger posterior tubercles connected by sometimes incomplete carinae; node in lateral view subquadrate, in dorsal view slightly longer than broad; in dorsal view, postpetiole > 1.5X broader than long; posteriorly emarginate; latero-posterior corners with inferior wing-like projections giving it a trapezoidal shape; shape of postpetiole, in profile, longer than higher (1.2-1.3X); tergite of abdominal segment IV punctulate-reticulate; in dorsal view, base of tergite at junction with postpetiole slightly carinate (as in all Myrmicocrypta spp.), but lacking lateral carinae beyond this junction, i.e., antero-lateral gastral carinae absent; pilosity on dorsum of abdominal tergite IV consisting of widely separated, extremely narrowly spatulate hairs, all curved at tips and directed backward.

Individuals brown ferruginous; pilosity restricted to wrinkles, tubercles, spines, carinae, appendages, antennal scapes, and gaster, absent elsewhere. Legs and antennal scapes strongly reticulate.

Type Material
Holotype. One worker, labeled: “Peru: Madre de Dios, Centro de Investigacion y Capacitacion Rio Los Amigos (CICRA), Otorongo Trail, 12°33’42.28’’ S 70°05’32.64’’ W, elevation 276 m, 19-XI-2005, (J. Sosa-Calvo), nest series, hand collected, forest (JSC051119-09)” ENT No. 00537326. .

Paratypes. Fourteen workers, part of the same nest series as holotype. (USNM). USNM ENT Nos. 00537307, 00537308, 00537317, 00537325, and 00301761 (alcohol); four workers, labeled: “Brazil: Amapa, Serra do Navio (Silverstone).” ( 42302). USNM ENT Nos. 00537306 and 00537316; 1 worker labeled: “Brazil, Amazonas, Manaus, 9-v-2003, (C. Rabeling and M. Verhaagh).” (USNM). USNM ENT No. 00537315.

Etymology
Named in honor of Dr. Peter Buck in recognition of his support for science at the Smithsonian’s National Museum of Natural History.

References based on Global Ant Biodiversity Informatics

 * Bezdeckova K., P. Bedecka, and I. Machar. 2015. A checklist of the ants (Hymenoptera: Formicidae) of Peru. Zootaxa 4020 (1): 101–133.
 * Sosa-Calvo J., and T. R. Schultz. 2010. Three remarkable new fungus-growing ant species of the genus Myrmicocrypta, with a reassessment of the characters that define the genus and its position within the Attini. Annals of the Entomological Society of America 103: 181-195.