Female. Length 4 1/2 lines.-Resembling O. haematodes, with the following differences: the mandibles more distinctly serrated, the sulcations on the sides of the face anteriorly, not so deeply impressed, or so smooth and shining, they also terminate before reaching the ocelli; the line running from the ocelli to the posterior margin of the vertex is not so deeply impressed; the most striking difference is to be found in the neuration of the wings; the discoidal cell is of a somewhat different form, and the externo-medial nervure is straight, and unites with the transverso-medial nervure at the basal angle of the discoidal cell; in other respects it scarcely differs from O. haematodes.
Hab. Fidjee Islands; Ceylon.
The difference pointed out in the neuration of the wings would appear to indicate a generic distinction; but an examination of a number of winged females shows a frequent approach to the neuration of the present species, and in specimens of the male of haematodes, taken with the female from the same nest, by Mr. Bates, the neuration is found to be identical with that of O. simillimus ; in the British Museum are two specimens from Ceylon which appear to be identical with the present species.
Fisher, B. L., 2008:
Figures: worker 12a,b, 13b; queen 12c,d; male 12e,f;
Worker measurements: maximum and minimum based on n = 10 from Madagascar: HL 2.33-2.63, HW (across vertex) 1.64- 2.03, HW (across upper eye margin) 1.77-2.06, CI 75-81, EL 0.20-0.23, ML 1.14-1.28, MI 48-51, SL 2.16-2.43, SI 109-123, WL 2.62-3.06. FL 2.29-2.56, PW 1.02-1.24.
Queen measurements: maximum and minimum based on n = 5 from Madagascar: HL 2.37-2.55, HW (across vertex) 1.79- 2.03, HW (across upper eye margin) 1.87-2.13, CI 79-84, EL 0.49-0.53, ML 1.17-1.30, MI 49-52, SL 2.15-2.38, SI 111-118, WL 3.13-3.19. FL 2.36-2.58.
Male measurements: maximum and minimum based on n = 1 from Madagascar: HL 0.89, HW 1.19, CI 133, EL 0.59, SL 0.19, SI 16, WL 2.44. FL 1.73.
Worker diagnosis: Workers and males are very similar in morphology and size to troglodytes Bivariate plots of metric measurements did not distinguish the two species. Workers and queen have fine, glossy dorsal striation on head and mesosoma. Metasternal process low and rounded (Fig. 13b). Metasternal process can be viewed in mounted specimens by removing a hind leg and coxa. Brown  provides a description and additional references.
Distribution and biology. Known though most of the literature as 'O. haematodes' (Linnaeus) 1758 which is a different species. Forel's [25:159] record of 'O. haematodes' from Seychelles, Mahe most likely refers to simillimus .
Found in clearings and secondary growth throughout the IndoPacific. The records from the Seychelles clearly represent an introduction. O. simillimus is not known from Madagascar and may have difficulty in establishing on Madagascar because of the presence of the morphologically and ecologically similar O. troglodytes .
CO1. The average within species CO1 divergence for O. simillimus was 3.212% with much variation between islands (Max 5.786, SE = 0.273). Importantly, although bivariate plots of worker measurements do not reliably separate O. simillimus from the ecologically similar O. troglodytes , the two species are, on average, 7-8% divergent within the CO1 barcode.
Diagnostic barcoding loci. O. simillimus : C-265, T-267, T- 528.
Specimens examined for Odontomachus simillimus :
Additional details are provided for the specimens from Seychelles.
INDONESIA : Irian Jaya , Maffin Bay ; PT. Freeport Concession, Siewa Camp ;PAPUA NEW GUINEA : Los Negros , Admiralty Islands ;Milne Bay , Morobe , Finschhafen , Biak Island ;PHILIPPINES : Leyte , Tacloban ;SEYCHELLES : Silhouette Island , Grande Barbe , 7/22-23/2000 , J.Gerlach ;Silhouette Island , Jardin Marron , 7/5/2000 , J.Gerlach ;SOLOMON ISLANDS : Kungana Bay , Rennell Island ;Guadalcanal , Tenaru River ;Kungana Bay , Rennell Island , Anuda Island ;NW end of Bellona Island ;Tevia Bay , Vanikoro Island , Santa Cruz Islands ;Mohawk Bay , Matema Island , Santa Cruz Islands , Pavuvu , Russell Island ;VANUATU : Espiritu Santo Island .
Smith, F., 1859:
Smith, Cat. Form, p. 80. 11 [[ queen ]]. Hab. Aru . Ceylon.