Published April 18, 2024. Open access.

Gallery ❯

Diamond Racer (Drymobius rhombifer)

Reptiles of Ecuador | Serpentes | Colubridae | Drymobius anomalus

English common names: Diamond Racer, Blotched Racer.

Spanish common names: Corredora diamante, culebra de rombos.

Recognition: ♂♂ 126.8 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=90.7 cm. ♀♀ 109.7 cmMaximum distance from the snout to the tip of the tail..1,2 Drymobius rhombifer is a medium-sized snake with keeled dorsal scales having a dark brown dorsum adorned with 16–24 diamond-shaped blotches featuring a pale brown center and dark edges (Fig. 1).15 The belly is creamy white, adorned with a series of tiny brown spots bordering the ventral scales.15 The head is uniformly brown, with large eyes and a bronze iris.3 This species differs from the similarly patterned Bothrops atrox, B. asper, and Xenodon rabdocephalus by lacking loreal pits and by having no dark postocular stripe.6,7

Figure showing variation among individuals of Drymobius rhombifer

Figure 1: Individuals of Drymobius rhombifer from Ecuador: Napo Wildlife Center, Orellana province (); Reserva Río Bigai, Napo province ().

Natural history: Drymobius rhombifer is a terrestrial snake that inhabits pristine lowland rainforests and floodplain forests, usually near ponds.14 The species occurs in lower densities, or not at all, in semi-open habitats or forest-edge situations. Diamond Racers are typically active on the forest floor during the daytime, frantically foraging on the leaf-litter or on low vegetation in search for food. At night, they roost on understory vegetation 0.9 to 2 m above the ground.2,4 The diet in this species consists of amphibians and lizards.2,4,5 The Diamond Racer, when cornered, opens the mouth aggressively and strikes. Its tail is long, fragile, and breaks off easily when grabbed by a predator, enabling the escape and survival of the snake.8 There is a recorded instance of predation on an individual of D. rhombifer by a hawk in Peru.9 An observation in Costa Rica indicates that courtship in this species occurs in July.10

Reader support helps us keep the Reptiles of Ecuador book 100% free.

Conservation: Least Concern Believed to be safe from extinction given current circumstances..11 Drymobius rhombifer is listed in this category because the species is widely distributed, occurs in many protected areas (at least 10 in Ecuador), and is considered to be facing no major immediate threats of extinction.11 In addition, it is presumed that populations of D. rhombifer are stable and largely unfragmented.11 However, this species, a strict forest dweller, is under constant threat due to large-scale deforestation driven by agricultural and urban expansion. Finally, because of its resemblance to Bothrops atrox, the Diamond Racer is often killed on sight whenever encountered.

Distribution: Drymobius rhombifer is widely distributed throughout the Neotropics, from Mexico to northwestern Ecuador (Fig. 2), as well as throughout much of Amazonia.

Distribution of Drymobius rhombifer in Ecuador

Figure 2: Distribution of Drymobius rhombifer in Ecuador. The star corresponds to the type locality: Esmeraldas, Esmeraldas province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The genus name Drymobius is derived from the Greek word drymos (=oak forest) and bios (=manner of life).12 The specific epithet rhombifer comes from the Latin rhombus (=diamond) and the suffix -fero (=provided with).12 It refers to the rhomboidal dorsal markings.

See it in the wild: Drymobius rhombifer is considered a rare species in Ecuador, with no more than 1–2 individuals recorded per year at any given locality. The areas having the greatest number of observations of this elusive serpent are Centro Científico Río Palenque and Yasuní Scientific Station.

Authors: Tatiana Molina-Moreno,aAffiliation: Departamento de Biología, Universidad de los Llanos, Villavicencio, Colombia. Andrés F. Aponte-Gutiérrez,bAffiliation: Grupo de Investigación en Ciencias de la Orinoquía, Universidad Nacional de Colombia sede Orinoquía, Arauca, Colombia.,cAffiliation: Fundación Biodiversa Colombia, Bogotá, Colombia. and Danna Duque-TorresdAffiliation: Grupo de Ornitología, Universidad Nacional de Colombia, Bogotá, Colombia.

Editor: Alejandro ArteagaeAffiliation: Tropical Herping (TH), Quito, Ecuador.

Photographers: Jose VieirafAffiliation: Tropical Herping (TH), Quito, Ecuador.,gAffiliation: ExSitu, Quito, Ecuador. and Amanda QuezadaeAffiliation: Tropical Herping (TH), Quito, Ecuador.

How to cite? Molina-Moreno T, Aponte-Gutierrez AF, Duque-Torres D (2024) Diamond Racer (Drymobius rhombifer). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/DXQC2118

Literature cited:

  1. Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
  2. Duellman WE (1978) The biology of an equatorial herpetofauna in Amazonian Ecuador. Publications of the Museum of Natural History, University of Kansas 65: 1–352.
  3. Savage JM (2002) The amphibians and reptiles of Costa Rica, a herpetofauna between two continents, between two seas. The University of Chicago Press, Chicago, 934 pp.
  4. Duellman WE (2005) Cusco amazónico: the lives of amphibians and reptiles in an Amazonian rainforest. Cornell University Press, Ithaca, 433 pp.
  5. Natera-Mumaw M, Esqueda-González LF, Castelaín-Fernández M (2015) Atlas serpientes de Venezuela. Dimacofi Negocios Avanzados S.A., Santiago de Chile, 456 pp.
  6. Campbell JA, Lamar WW (2004) The venomous reptiles of the western hemisphere. Cornell University Press, Ithaca, 774 pp.
  7. Valencia JH, Garzón-Tello K, Barragán-Paladines ME (2016) Serpientes venenosas del Ecuador: sistemática, taxonomía, historial natural, conservación, envenenamiento y aspectos antropológicos. Fundación Herpetológica Gustavo Orcés, Quito, 653 pp.
  8. Padilla-Pérez DJ, Murillo-Monsalve JD, Rincon-Barón EJ, Daza JM (2015) Non-specialized caudal pseudoautotomy in the Emerald Racer snake Drymobius rhombifer (Günther, 1860). Herpetology Notes 8: 567–569.
  9. Leite Pitman R, Champagne PS (2022) Drymobius rhombifer (Esmarald Racer): predation. Herpetological Review 53: 340.
  10. Leenders T (2019) Reptiles of Costa Rica: a field guide. Cornell University Press, Ithaca, 625 pp.
  11. Vargas Álvarez J, García Rodríguez A, Batista A, Acosta Chaves V, Nogueira CC, Gonzales L, Cisneros-Heredia DF, Gagliardi G, Hoogmoed MS (2019) Drymobius rhombifer. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-2.RLTS.T176799A1446864.en
  12. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.

Appendix 1: Locality data used to create the distribution map of Drymobius rhombifer in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

ColombiaCaquetáBelén de AndaquíesRuiz Valderrama 2023
ColombiaNariñoTangareal del MiraDickey 2016
ColombiaPutumayoCentro Experimental AmazónicoiNaturalist; photo examined
ColombiaPutumayoEl TigreiNaturalist; photo examined
ColombiaPutumayoFinca MariposaCalderon et al. 2023
ColombiaPutumayoVereda ZarsalNogueira et al. 2019
EcuadorEsmeraldasCanandé Biological ReserveiNaturalist; photo examined
EcuadorEsmeraldasEsmeraldas*Günther 1860
EcuadorLos RíosCentro Científico Río PalenqueMCZ R-149669; VertNet
EcuadorLos RíosHacienda Cerro ChicoMCZ 151577; VertNet
EcuadorLos RíosPatricia Pilar, 4 km SW ofRMNH 50717
EcuadorLos RíosSan Jacinto de Buena FeMCZ R-151577; VertNet
EcuadorMorona SantiagoChumbelaNogueira et al. 2019
EcuadorMorona SantiagoComunidad AmazonasiNaturalist; photo examined
EcuadorMorona SantiagoMacasAMNH 28831; examined
EcuadorMorona SantiagoMacumaiNaturalist; photo examined
EcuadorMorona SantiagoNormandíaAMNH 23270; examined
EcuadorMorona SantiagoRío YaupiNogueira et al. 2019
EcuadorMorona SantiagoSoldado MongeiNaturalist; photo examined
EcuadorMorona SantiagoTurulaAMNH 35963; examined
EcuadorNapoAhuanoiNaturalist; photo examined
EcuadorNapoChontapuntaiNaturalist; photo examined
EcuadorNapoEl BombónKU 121880; VertNet
EcuadorNapoEl Carmen, 3 km SE ofiNaturalist; photo examined
EcuadorNapoJatun Sacha Biological StationHernández-Sánchez 2013
EcuadorNapoReserva Río BigaiThis work; Fig. 1
EcuadorNapoRío SunoNogueira et al. 2019
EcuadorNapoTenaiNaturalist; photo examined
EcuadorOrellanaÁvilaNogueira et al. 2019
EcuadorOrellanaFlorencia Nogueira et al. 2019
EcuadorOrellanaLoretoNogueira et al. 2019
EcuadorOrellanaNapo Wildlife CenterThis work; Fig. 1
EcuadorOrellanaPozo NashiñoAMNH 57344; examined
EcuadorOrellanaPrimaveraMHNG 2398.009; collection database
EcuadorOrellanaSan Jose de DahuanoUMMZ 92043; VertNet
EcuadorOrellanaTiputini Biodiversity StationReptiles of Ecuador book database
EcuadorOrellanaYarina LodgeiNaturalist; photo examined
EcuadorOrellanaYasuní Scientific StationNogueira et al. 2019
EcuadorPastazaChontoaKU 121333; VertNet
EcuadorPastazaConamboOrtega-Andrade 2010
EcuadorPastazaCopatazaNogueira et al. 2019
EcuadorPastazaIndillamaKU 121333; VertNet
EcuadorPastazaMontalvoNogueira et al. 2019
EcuadorPastazaRío MaritayacuNogueira et al. 2019
EcuadorPastazaRío TigreUSNM 204121; VertNet
EcuadorPastazaSantanaNogueira et al. 2019
EcuadorPastazaSarayacuUSNM 204124; VertNet
EcuadorPastazaShellNogueira et al. 2019
EcuadorPastazaSimón BolívarSMF 90955; VertNet
EcuadorPastazaTamboNogueira et al. 2019
EcuadorPastazaVía Puyo–TenaNogueira et al. 2019
EcuadorPichinchaPuerto QuitoMHNG 2250.050; collection database
EcuadorPichinchaReserva Mashpi ShungoiNaturalist; photo examined
EcuadorSucumbíosCooperativa Río OriencoiNaturalist; photo examined
EcuadorSucumbíosEl ReventadorMHNG 2398.008; collection database
EcuadorSucumbíosHostería La SelvaNogueira et al. 2019
EcuadorSucumbíosLimoncocha Biological ReserveiNaturalist; photo examined
EcuadorSucumbíosLumbaqui, 15 km ENE ofKU 121878; VertNet
EcuadorSucumbíosPuerto LibreNogueira et al. 2019
EcuadorSucumbíosReserva CuyabenoNogueira et al. 2019
EcuadorSucumbíosRío Auca–YacoNogueira et al. 2019
EcuadorSucumbíosSan Pablo de KantesiyaMHNG 2306.011; collection database
EcuadorSucumbíosSanta Cecilia Duellman 1978
EcuadorZamora ChinchipeRío ZamoraUMMZ 82892; VertNet
EcuadorZamora ChinchipeSubcuenca del Río TundaymeBetancourt et al. 2018
PeruAmazonasRío CenepaMVZ 163272; VertNet
PeruLoretoAndoas Nogueira et al. 2019