Published June 8, 2022. Open access.

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Highland Pygmy-Boa (Tropidophis taczanowskyi)

Reptiles of Ecuador | Serpentes | Tropidophiidae | Tropidophis taczanowskyi

English common names: Highland Pygmy-Boa, Taczanowsky’s Dwarf Boa.

Spanish common names: Boa pigmea de altura, boa pigmea suroriental, boa pigmea de Taczanowsky.

Recognition: ♂♂ 38.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=33.5 cm. ♀♀ 39.1 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=34.8 cm..1 Tropidophis taczanowskyi is a small stout-bodied serpent that differs from other snakes in the high Andes of southern Ecuador by having the following combination of characters: laterally compressed body, keeled dorsal scales arranged in 23 rows at mid-body, short tail, dark brown dorsum (Fig. 1), and orangish cream ventral surfaces.13 There are no significant differences in size or coloration between males and females of T. taczanowskyi.1 The shape of the body and the slow-moving habits of the Highland Pygmy-Boa are enough to separate this species from other small brownish co-occurring snakes such as Atractus carrioni, Dipsas jamespetersi, and Erythrolamprus fraseri.

Figure showing variation among individuals of Tropidophis taczanowskyi

Figure 1: Individuals of Tropidophis taczanowskyi from Abra de Zamora, Zamora Chinchipe province, Ecuador.

Natural history: Tropidophis taczanowskyi is a rarely seen high-elevation snake species adapted to life in the cloud forest and the humid montane shrubland ecosystem. Highland Pygmy-Boas are slow-moving and lethargic diurnal snakes usually found under rocks, timber, and other surface objects in semi-open dry or swampy areas near forest border.4 Their diet includes frogs,4,5 tadpoles,4 and possibly lizards.2 Members of the genus Tropidophis in general are notable for their cephalic autohemorrhaging defense behavior, which includes expelling blood from the eyes and the mouth when the animal is under stress.6 This behavior has also been observed in individuals of T. taczanowskyi in addition to their tendency to roll into a tight ball while hiding the head among body coils.4 This species gives birth to live young. One gravid female contained five fully developed embryos about 7.6 cm in total length.3

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Conservation: Near Threatened Not currently at risk of extinction, but requires some level of management to maintain healthy populations..5,7 Tropidophis taczanowskyi is included in this category because the species is widely distributed and occurs over an area of the Amazonian slopes of the Andes that holds large areas of continuous unspoiled forest. Based on the most recent maps of vegetation cover of the Amazon basin,8 the majority (~80%) of the species’ forest habitat in Ecuador is still standing. In Ecuador, T. taczanowskyi occurs in the Cerro Plateado Biological Reserve and in the Podocarpus National Park. The most important threat to the long-term survival of some populations of this species is habitat destruction due to the expansion of the agricultural frontier, the construction of roads, and mining activities.5

Distribution: Tropidophis taczanowskyi is native to the Amazonian slopes of the Andes, as well as some inter-Andean valleys, in southern Ecuador (Fig. 2) and northern Perú.

Distribution of Tropidophis taczanowskyi in Ecuador

Figure 2: Distribution of Tropidophis taczanowskyi in Ecuador. The star corresponds to the type locality: Tambillo, Cajamarca department, Peru. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The name Tropidophis comes from the Greek words tropis (=keel) and ophis (=serpent),9 referring to the keeled scales of the type species.10 The species’ name honors Polish zoologist and collector Władysław Taczanowski (1819–1890), who explored the Russian Far East and northern Africa. He is best known for his ornithological work but he also described other species including reptiles and arachnids.11

See it in the wild: In Ecuador, the best areas to find Highland Pygmy-Boas are Tapichalaca Reserve and the old road connecting the cities Loja and Zamora. Finding these snakes requires targeted search efforts involving flipping hundreds of surface objects near the forest edge.

Special thanks to Kortnie Cohn for symbolically adopting the Highland Pygmy-Boa and helping bring the Reptiles of Ecuador book project to life.

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Authors: Amanda Quezada,aAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: Laboratorio de Herpetología, Universidad del Azuay, Cuenca, Ecuador. Jose Vieira,aAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador. and Alejandro ArteagadAffiliation: Khamai Foundation, Quito, Ecuador.

Photographer: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador.

How to cite? Quezada A, Vieira J, Arteaga A (2022) Highland Pygmy-Boa (Tropidophis taczanowskyi). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/NEWJ6535

Literature cited:

  1. Curcio FF, Sales Nunes PM, Argolo AJS, Skuk G, Rodrigues MT (2012) Taxonomy of the South American dwarf boas of the genus Tropidophis Bibron, 1840, with the description of two new species from the Atlantic Forest (Serpentes: Tropidophiidae). Herpetological Monographs 26: 80–121. DOI: 10.1655/HERPMONOGRAPHS-D-10-00008.1
  2. Hedges SB (2002) Morphological variation and the definition of species in the snake genus Tropidophis (Serpentes, Tropidophiidae). Bulletin of The Natural History Museum 68: 83–90. DOI: 10.1017/S0968047002000092
  3. Griffith Stull O (1928) A revision of the genus Tropidophis. Occasional Papers of the Museum of Zoology, University of Michigan 195: 1–49.
  4. Field notes, Reptiles of Ecuador book project.
  5. Yánez-Muñoz M, Brito J, Cisneros-Heredia DF (2019) Tropidophis taczanowskyi. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-2.RLTS.T50952126A50952178.en
  6. Iturriaga M (2014) Autohemorrhaging behavior in the Cuban dwarf boa Tropidophis melanurus Schlegel, 1837 (Serpentes: Tropidophiidae). Herpetology Notes 7: 339–341.
  7. Reyes-Puig C (2015) Un método integrativo para evaluar el estado de conservación de las especies y su aplicación a los reptiles del Ecuador. MSc thesis, Pontificia Universidad Católica del Ecuador, 73 pp.
  8. MapBiomas Amazonía (2022) Mapeo anual de cobertura y uso del suelo de la Amazonía. Available from:
  9. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
  10. Cocteau JT, Bibron G (1843) Reptiles. In: de la Sagra R (Ed) Historia física, política y natural de la isla de Cuba. Arthus Bertrand, Paris, 1–142.
  11. Beolens B, Watkins M, Grayson M (2011) The eponym dictionary of reptiles. Johns Hopkins University Press, Baltimore, 296 pp.

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

EcuadorLojaLoja, 1.7 km E ofCurcio et al. 2012
EcuadorLojaLoja, 18 km E ofMHNG 2237.100
EcuadorLojaMadrigal del PodocarpusPaul Szekely, pers. comm.
EcuadorLojaParque JipiroPaul Szekely, pers. comm.
EcuadorLojaSan Lucas, 6 km NE ofCurcio et al. 2012
EcuadorLojaTapichalaca Biological ReserveThis work
EcuadorLojaYangana, 13 km S ofField notes of John Wiens
EcuadorZamora ChinchipeAbra de ZamoraThis work
EcuadorZamora ChinchipeBorder between Podocarpus and TapichalacaTorres-Carvajal et al. 2019
EcuadorZamora ChinchipeCerro ImbanaCurcio et al. 2012
EcuadorZamora ChinchipeCerro PlateadoAlmendáriz et al. 2014
EcuadorZamora ChinchipeDivisoria CajanumaMCZ 93584
EcuadorZamora ChinchipeEstación Científica San FranciscoThis work
EcuadorZamora ChinchipeLoja, 16.6 km E ofCurcio et al. 2012
EcuadorZamora ChinchipeParque Nacional PodocarpusLACM 147182
EcuadorZamora ChinchipeSabanillaMZUA.RE.0123
PeruCajamarcaSan Andrés de CutervoKU 221728
PeruCajamarcaSantuario Nacional Tabaconas NamballeINRENA 2007
PeruCajamarcaTambillo*Steindachner 1880
PeruPiuraProyecto Minero Río BlancoMINEM 2008