Published January 10, 2024. Open access.

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Yellow-spotted Puffing-Snake (Phrynonax shropshirei)

Reptiles of Ecuador | Serpentes | Colubridae | Phrynonax shropshirei

English common names: Yellow-spotted Puffing-Snake, Shropshire’s Puffing Snake.

Spanish common names: Culebra estrella, culebra tigre, culebra silbadora (Ecuador); toche, voladora (Colombia).

Recognition: ♂♂ 163 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=120 cm..1 Phrynonax shropshirei differs from other large diurnal snakes in western Ecuador by having scales arranged in 25 rows at mid-body, of which the three median rows are feebly keeled.2 The coloration is also diagnostic. Adults have a black dorsum with bright yellow spots and a yellow belly (Fig. 1). Juveniles have a pale brown dorsum with transverse bands and a whitish belly with brown streaks. Adults of P. shropshirei resemble Spilotes megalolepis and Chironius flavopictus. However, the combination of high number of dorsal scale rows and the bright yellow belly is only present in P. shropshirei.3

Figure showing variation among individuals of Phrynonax shropshirei

Figure 1: Individuals of Phrynonax shropshirei: Canandé Biological Reserve, Esmeraldas province, Ecuador (); Morromico, Chocó department, Colombia (); Azuay province, Ecuador (). j=juvenile.

Natural history: Phrynonax shropshirei is a terrestrial and semi-arboreal snake that inhabits pristine to heavily disturbed rainforests, seasonally dry forests, and savannas.2 The species also occurs in plantations and rural gardens.4 During the day, these snakes forage both at ground level or on trees.4 At night, they typically roost on shrubs and trees, but are also occasionally found coiled on the thatch of roofs and pillars in man-made structures.4 Yellow-spotted Puffing-Snakes are active hunters having an aglyphous dentition, meaning their teeth lack specialized grooves to deliver venom.3 Their diet includes birds and their eggs.5,6 Puffing snakes are known for their defense behavior. When threatened, they keep the anterior half of the body elevated in an “S” shape, while compressing it laterally and inflating the neck.4 With the mouth open, they produce a hissing sound and strike the observer.7 In southwestern Ecuador, four males were seen pursuing and trying to mate with a single female in February.8

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..9 Phrynonax shropshirei is listed in this category primarily on the basis of the species’ wide distribution, presence in protected areas, and adaptability to habitat modification provided there is tree cover remaining.9 The most important threat to some populations is deforestation and habitat fragmentation. The survival of this arboreal snake is contingent upon the availability of trees, as they serve both as protective cover against predators and as a source of forage.9,10

Distribution: Phrynonax shropshirei is widely distributed throughout the lowlands and adjacent mountain foothills of the Chocó biogeographic region, from Panama, through Colombia, to northwestern Ecuador (Fig. 2). The species also occurs throughout the valley regions of the rivers Cauca and Magdalena in Colombia.

Distribution of Phrynonax shropshirei in Ecuador

Figure 2: Distribution of Phrynonax shropshirei in Ecuador. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The generic name Phrynonax comes from the Greek words phryne (=toad) and anax (=king),11 and roughly translates to “master of the toads.” The specific name shropshirei honors James Shropshire, a member of the U.S. Army who collected this species at the Canal Zone of Panama in 1924.12

See it in the wild: Yellow-spotted Puffing-Snakes are seen at a rate of about once every few weeks in forested localities throughout their area of distribution in Ecuador. The locality having the greatest number of observations is Buenaventura Biological Reserve. These snakes can be spotted at night, sleeping on vegetation, or foraging on the ground during sunny days.

Special thanks to David Whitacre for symbolically adopting the Yellow-spotted Puffing-Snake and helping bring the Reptiles of Ecuador book project to life.

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Authors: Gabriela SandovalaAffiliation: Pontificia Universidad Católica del Ecuador, Quito, Ecuador. and Alejandro ArteagabAffiliation: Khamai Foundation, Quito, Ecuador.

Photographers: Jose VieiracAffiliation: Tropical Herping (TH), Quito, Ecuador.,dAffiliation: ExSitu, Quito, Ecuador. and Sebastián Di DoménicoeAffiliation: Keeping Nature, Bogotá, Colombia.

How to cite? Sandoval G, Arteaga A (2024) Yellow-spotted Puffing-Snake (Phrynonax shropshirei). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/JJKC8826

Literature cited:

  1. Barbour T, Amaral A (1924) Notes on some Central American snakes. Occasional Papers of the Boston Society of Natural History 5: 129–132.
  2. MECN (2010) Serie herpetofauna del Ecuador: El Chocó esmeraldeño. Museo Ecuatoriano de Ciencias Naturales, Quito, 232 pp.
  3. Suárez AM, Alzate E (2014) Guía ilustrada de anfibios y reptiles de Cañón del Río Porce. Universidad de Antioquia, Medellín, 138 pp.
  4. Field notes, Reptiles of Ecuador book project.
  5. Zuluaga Isaza JC, Rojas-Morales JA, Díaz-Ayala RF, Ramírez-Castaño VA (2015) Pseustes shropshirei (Shropshire’s Puffing Snake): diet. Herpetological Review 46: 649.
  6. Cisneros-Heredia DF (2005) Pseustes poecilonotus and Pseustes shropshirei (Puffing Snakes): diet. Herpetological Review 36: 326–327.
  7. Rand AS, Ortleb EP (1969) Defensive display in the colubrid snake Pseustes poecilonotus shropshirei. Herpetologica 25: 46–48.
  8. Video by Leodán Aguilar.
  9. Cisneros-Heredia DF, Valencia J, Arredondo JC, Daza J (2014) Phrynonax shropshirei. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2017-2.RLTS.T15183756A15183764.en
  10. Carvajal-Cogollo JE, Rojas-Murcia LE, Cárdenas-Arévalo G (2020) Reptiles del Caribe Colombiano. Editorial Universidad Pedagógica y Tecnológica de Colombia, Tunja, 268 pp.
  11. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
  12. 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 Phrynonax shropshirei in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

ColombiaNariñoBarbacoasFlickr; photo examined
ColombiaNariñoLa Esperanza, 0.2 km W ofiNaturalist; photo examined
ColombiaNariñoMar AgrícolaPinto-Erazo et al. 2020
EcuadorAzuayPonce EnríqueziNaturalist; photo examined
EcuadorCarchiAwá Indian PreserveiNaturalist; photo examined
EcuadorCarchiDestacamento Militar Tobar DonosoYánez-Muñoz et al. 2009
EcuadorCotopaxiGuasaganda, 7 km W ofiNaturalist; photo examined
EcuadorCotopaxiLa CarmelaiNaturalist; photo examined
EcuadorEl OroLa Esperanza, 0.9 km W ofiNaturalist; photo examined
EcuadorEl OroPasaje, 10 km E ofiNaturalist; photo examined
EcuadorEl OroReserva BuenaventuraGarzón-Santomaro et al. 2019
EcuadorEsmeraldasBilsa Biological StationOrtega-Andrade et al. 2010
EcuadorEsmeraldasBosque Protector La ChiquitaPhoto by William Lamar
EcuadorEsmeraldasCanandé Biological ReserveiNaturalist; photo examined
EcuadorEsmeraldasMompiche, 2 km S ofiNaturalist; photo examined
EcuadorEsmeraldasPalma Real, 6.4 km NE ofiNaturalist; photo examined
EcuadorEsmeraldasSan Lorenzo, 10.5 km S ofiNaturalist; photo examined
EcuadorEsmeraldasTongorachi, 4.7 km E ofFlickr; photo examined
EcuadorEsmeraldasTundaloma LodgeReptiles of Ecuador book database
EcuadorGuayasCerro de HayasPazmiño-Otamendi 2020
EcuadorGuayasDuránYPM 007962; VertNet
EcuadorGuayasGuayaquilPhoto by Eduardo Zavala
EcuadorGuayasManglaralto, 2.6 km NE ofCM 9924; VertNet
EcuadorGuayasRancho Aleman, 1 km S ofSymbiota INABIO Record
EcuadorImbaburaLita, 30 km E ofMHNG 2531.048; photo examined
EcuadorImbaburaReserva Cotacachi CayapasiNaturalist; photo examined
EcuadorLos RíosCentro Científico Río PalenqueMHNG 2398.054; collection database
EcuadorManabíReserva Bosque Seco Lalo LooriNaturalist; photo examined
EcuadorManabíReserva Jama-CoaqueLynch et al., 2016
EcuadorManabíReserva Jama-Coaque, 4 km NW ofiNaturalist; photo examined
EcuadorManabíSucreHerpMapper; photo examined
EcuadorPichinchaMashpi Lodge ReserveMedina 2021
EcuadorPichinchaPedro Vicente Maldonado, 4.3 km W ofiNaturalist; photo examined
EcuadorPichinchaPuerto Quito, 10 km E ofiNaturalist; photo examined
EcuadorPichinchaPuerto Quito, 6.4 km E ofiNaturalist; photo examined
EcuadorPichinchaRío Silanche Wildlife SanctuaryiNaturalist; photo examined
EcuadorSanta ElenaFinca La SelvaiNaturalist; photo examined
EcuadorSanto Domingo de los TsáchilasMulaute, 3 km W ofiNaturalist; photo examined