this material is and what function it serves also needs

96
Michael G. Branstetter / ZooKeys 295: 1–277 (2013)
this material is and what function it serves also needs investigation. Given their nesting
habits, it is somewhat odd that the collection of the type series was made “beneath a
stone.” Perhaps this was on clay bank.
Comments. Stenamma diversum and S. tico are sister species and together form the
diversum species group. This group is defined by the following characters: head mostly
smooth and shiny; mesosoma mostly reticulately costate; promesonotum in profile lowdomed, roughly symmetrical; postpetiole in profile without a distinct dorsal lobe that
projects posteriad over postpetiole (as in S. lobinodus and other lobinodus group species);
basal margin of mandible straight; anterior clypeal margin with a median emargination.
Based on DNA sequence data S. vexator is likely sister to the diversum species group, but
morphological characters could not be found to diagnose the entire clade.
Stenamma diversum is probably the most distinctive Stenamma species, but it does
bear some similarity to its sister taxon S. tico and the more distantly related S. lobinodus, both of which share roughly the same color and sculpture pattern. It is easy to
separate S. diversum from these other species by comparing the propodeal spines and
the frontal lobes. In S. tico, the spines are absent or at most form small dorsally projecting tubercles (PSL 0.14–0.18, PSI 1.4–1.9). In S. lobinodus, the propodeal spines are
usually well developed, but they are shorter than those of S. diversum (PSL < 0.23 vs. >
0.27, PSI < 2.6 vs. > 3.0). Stenamma diversum is the only species among these three to
have greatly expanded frontal lobes, causing the underlying torular lobes to be covered
in full-face view. In the other species, the torular lobes are always visible. The frontal
lobes of S. lobinodus are especially reduced. Geography also can help separate these species. Stenamma diversum occurs in sympatry with S. lobinodus only in Oaxaca, Mexico
(although never collected together at the same site) and with S. tico only in northern
Nicaragua (found in sympatry at Cerro Saslaya and Cerro Musún).
Material examined. BELIZE: Cayo: Caves Branch, [ca. 17.13°N, 88.70°W], 4-14
Aug 1972 (S. & J. Peck); GUATEMALA: Alta Verapaz: Muchbilhá, 15.86966°N,
90.14254°W, 184m, 9 Nov 2009 (L. Sáenz); Izabal: Carboneras Sn. Gil, 15.63728°N,
88.82826°W, 415m, 19 Nov 2009 (L. Sáenz); 5km NW Morales, 15.51441°N,
88.86459°W, 250m, 17 May 2009 (LLAMA); 16km ESE Morales, 15.41186°N,
88.71671°W, 410m, 19 May 2009 (LLAMA); Finca La Firmeza, 10.7km SE Morales,
15.4067°N, 88.6967°W, 500m, 19 Sep 2008 (M. G. Branstetter); Petén: 13km NW
Machaquilá, 16.44603°N, 89.54940°W, 400m, 27 May 2009 (LLAMA); HONDURAS:
Comayagua: P.N. Cerro Azul Meambar, 14.86601°N, 87.89955°W, 880m, 21 May 2010
(LLAMA); P.N. Cerro Azul Meambar, 3.4km ESE La Guama, 14.8722°N, 87.9053°W,
760m, 26 Sep 2008 (M. G. Branstetter); Gracias a Dios: Las Marias, 15.72245°N,
84.88078°W, 510m, 10 Jun 2010 (LLAMA); Las Marias, 15.71844°N, 84.87811°W,
370m, 10 Jun 2010 (M. G. Branstetter); Olancho: 11km NNE Catacamas, 14.94493°N,
85.84928°W, 1100m, 12 May 2009 (J. Longino); MEXICO: Chiapas: Lago Metzabok, 17.12622°N, 91.63056°W, 570m, 5 Jun 2008 (LLAMA); Nahá, 16.97444°N,
91.58702°W, 180m, 24 Jun 2008 (LLAMA); Ocosingo, [approx. 16.906°N, 92.099°W],
2 Jun 1969 (J. M. Campbell); Playón de la Gloria, 16.14826°N, 90.89704°W, 180m,
24 Jun 2008 (LLAMA); Oaxaca: 5.7km SW Valle Nacional, 17.73067°N, 96.3304°W,