Hylomyrma dentiloba

The species inhabits sites at elevations from 90 to 100 m. Some specimens were sampled in leaf-litter, which suggests that this species nests between leaves, in fallen logs, rotten wood, or inside natural cavities of the superficial soil layers. (Ulyssea & Brandao, 2021)

Identification
Head dorsum with regular and longitudinal striae, mesial striation in part directed to posterior margin and in part anteriorly divergent and posteriorly convergent, interspaces distinguishable; mesosoma covered with regular to irregular and adjacent striae of variable thickness; dorsal margin of petiole discontinuous, dorsum with same striation of mesosoma lateral; subtriangular projection on mesoventral surface of petiole; subpostpetiolar process weak, convex; transverse striae on profemur posterior surface; protibia extensor surface striate; striation on tergum of first gastral segment restricted to base.

Hylomyrma dentiloba is similar to Hylomyrma blandiens, Hylomyrma jeronimae, and Hylomyrma macielae. Hylomyrma dentiloba and H. jeronimae are restricted to Central America (Figs. 84, 86), co-occuring in Barro Colorado Island, Panama, whereas H. blandiens shows a broad distribution in northwestern South America, from Bolivia to French Guiana (Fig. 84), overlapping in part with the area of distribution of H. macielae (south Colombia and the centernorth of Ecuador) (Fig. 86).

Hylomyrma dentiloba can be distinguished from H. blandiens (characteristic in parentheses) in the indistinguishable interspaces on head dorsum striation (vs. distinguishable), the straight dorsal margin of mesonotum (vs. convex), the propodeal spine shorter than the dorsal tooth of propodeal lobe (vs. slightly longer), and the striae length on the first gastral segment shorter to the postpetiole length (vs. similar than the postpetiole length).

Hylomyrma dentiloba can be distinguished from H. jeronimae in the regular striae on the mesial region of the head dorsum in part directed towards the posterior margin and in part anteriorly divergent and posteriorly convergent (vs. regular to irregular striae and divergent), the drop-shaped eye (vs. reniform), the longitudinal striation on the mesosomal dorsum (vs. striae assuming multiple directions), and the discontinuous dorsal margin of petiole (vs. continuous).

Hylomyrma dentiloba can be distinguished from H. macielae in the drop-shaped eye (vs. oval), and the straight dorsal margin of the mesonotum (vs. convex).

In molecular analysis, the specimens of H. dentiloba from Barro Colorado Island were separated into two clusters: (H. cf. dentiloba sp.1 (H. plumosa (H. cf. dentiloba sp.2, H. versuta))) (Pierce et al. 2017). After observing the images of H. cf. dentiloba sp.1 (CASENT0636001) from Costa Rica, we understand that this morphospecies is H. jeronimae and that H. cf. dentiloba sp.2 is the true H. dentiloba. The voucher specimens of sp.2 still need to be examined. Also, Pierce et al. (2017) stated that H. dentiloba and H. versuta are morphologically identical, being differentiated only in their geographical distribution. The authors use H. dentiloba to refer to H. dentiloba-like material from the Osa Peninsula of Costa Rica south through Panama, and H. versuta for material from the Atlantic slope of Costa Rica northward. However, we found that H. dentiloba (the H. cf. dentiloba sp.2) can be distinguished from H. versuta in the striation with indistinguishable interspaces on the head dorsum (vs. striation with distinguishable interspaces), the mesosoma and petiolar node covered by thinner striae with indistinguishable interspaces superimposed on irregular and thicker striae (vs. thinner striae with indistinguishable interspaces between irregular and thicker striae), the profemur covered with regular and transverse striae weakly marked (vs. predominantly smooth), the protibia mainly covered with regular and weakly marked striae (vs. predominantly smooth), and the shorter striae on tergum of the first gastral segment (vs. longer striae). Hylomyrma dentiloba can be distinguished from H. jeronimae (the H. cf. dentiloba sp.1) as mentioned in the previous paragraph.

Distribution
Panama, Costa Rica (Osa Peninsula).

Distribution based on Regional Taxon Lists
Neotropical Region: Costa Rica, Panama.

Nomenclature

 * . Lundella dentiloba Santschi, 1931c: 271 (w.) PANAMA.
 * Type-material: holotype worker.
 * Type-locality: Panama: France Field, 2.vi.1930 (A. Bierig).
 * Type-depository: NHMB.
 * Ulysséa & Brandão, 2021: 40 (q.).
 * Combination in Hylomyrma: Kempf, 1960f: 430.
 * Status as species: Kempf, 1964e: 52 (redescription), 55 (in key); Kempf, 1972a: 118; Kempf, 1973b: 238 (redescription); Kutter, 1977a: 88; Bolton, 1995b: 213; Branstetter & Sáenz, 2012: 258; Pierce, M.P., Branstetter, et al. 2017: 137; Ulysséa & Brandão, 2021: 40 (redescription).
 * Distribution: Panama.

Type Material
Pierce et al. (2017) and Ulyssea & Brandao (2021): Holotype worker: Panama, France Field, 2 June 1930 (A. Bierig), CASENT0913528].

Worker
Pierce et al. (2017) - (n = 3): EL 0.194 - 0.233, EW 0.121 - 0.126, GSL 0.152 - 0.295, HFL 0.706 - 0.783, HL 0.778 - 0.855, HW 0.71 - 0.835, ML 0.977 - 1.115, OMD 0.092 - 0.104, PpL 0.227 - 0.251, PpW 0.293 - 0.35, PronW 0.512 - 0.625, SL 0.548 - 0.591, SPL 0.196 - 0.241, CI 91 - 98, GSI 15 - 26, OI 27 - 30, PpWI 129 - 139, SI 71 - 82, SPI 28 - 31.

References based on Global Ant Biodiversity Informatics

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 * INBio Collection (via Gbif)
 * Kempf W. W. 1973. A revision of the Neotropical myrmicine ant genus Hylomyrma Forel (Hymenoptera: Formicidae). Studia Entomologica 16: 225-260.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
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 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
 * Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Longino, J.T. 2010. Personal Communication. Longino Collection Database
 * Maes, J.-M. and W.P. MacKay. 1993. Catalogo de las hormigas (Hymenoptera: Formicidae) de Nicaragua. Revista Nicaraguense de Entomologia 23.
 * Pierce M. P., M. G. Branstetter, and J. T. Longino. 2017 . Integrative taxonomy reveals multiple cryptic species within Central American Hylomyrma FOREL, 1912 (Hymenoptera: Formicidae). Myrmecological News 25: 131-143.
 * Santschi F. 1931. Fourmis de Cuba et de Panama. Revista de Entomologia (Rio de Janeiro). 1: 265-282.
 * Smith M. A., W. Hallwachs, D. H. Janzen. 2014. Diversity and phylogenetic community structure of ants along a Costa Rican elevational gradient. Ecography 37(8): 720-731.