A revision and key for the tribe Diaphorolepidini (Serpentes: Dipsadidae) and checklist for the genus Synophis Author Pyron, R. Alexander Author Arteaga, Alejandro Author Echevarría, Lourdes Y. Author Torres-Carvajal, Omar text Zootaxa 2016 4171 2 293 320 journal article 10.11646/zootaxa.4171.2.4 9529a751-bd3c-46a8-83d7-ea7641844e11 1175-5326 158885 CDE07944-2354-477E-A3DA-61B713858D0C 4. Synophis calamitus Hillis, 1990 Range. Pacific Andean slopes of central and northern Ecuador , primarily in Pichincha , Santo Domingo de los Tsáchilas , and Cotopaxi provinces, ~ 1000–2300m . Populations also occur in Carchi province (~ 1900m ), and possibly Chimborazo province (~ 800m ; see below). Description. Adult size ~ 330–510mm SVL and ~ 190–280mm TL (assuming> 330mm SVL is adult), smooth nuchal scales; no nuchal collar; intranasals usually in contact but occasionally divided by rostral; usually 2 postoculars but occasionally 0 or 1; 8–11 infralabials; 7–9 supralabials; 157–166 ventrals; 96–125 subcaudals including possibly truncated tails, 100–113 in females, 109–118 in males; and (19–23)-19-17 dorsal scale-rows with single, weak keel. Notes. Includes a much larger range of specimens identified as Synophis aff. bicolor from the western Andes by Pyron et al. (2015) . The specimen from Carchi province in northern Ecuador (QCAZ5847) is morphologically identical to other S. calamitus populations ( Torres-Carvajal et al. 2015 ), but genetically distinct from the central Ecuadorean populations ( Figs. 1 , 4 ). There is thus intraspecific genetic diversity in S. calamitus , possibly related to the Río Mira as a geographic barrier to gene flow. The southernmost specimen, from Chimborazo province (CAS23612; Fig. 4 ), resembles both S. calamitus and S. zaheri . We refer it here to S. calamitus , for which it is a southern range extension, but it may represent a northern range extension for S. zaheri or a new species. Collecting effort in this locality should be a priority.