Glass frog

An unidentified Glass frog (Centrolenidae) from an unknown locality. I suppose it could be a Reticulated Glass Frog, Hyalinobatrachium valerioi, but perhaps you, expert zoologists and herpetologists in Tumblr, could help with the ID of this frog. 

Photo credit: ©Nicolas Reusens | Locality: unknown

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Glass frogs hold no secrets
Mother Nature Network

Photographer Andrew Snyder writes,

This glass frog (Hyalinobatrachium cf. cappellei) is a very small juvenile that was found on a small riverside branch along the Essequibo River on afternoon.

Currently Guyana has six species of glass frogs recorded for the country, and many of those look quite similar to each other. This image shows clearly why glass frogs get their name, but is also a way to make species identification possible.

The underside gives a clear view as to what color the bones are (typically either white or green) and whether certain organs such the heart are visible, all important diagnostic characteristics.


Yellow dotted glass frog (Hyalinobatrachium aureoguttatumby Santiago Ron:
“Glass frogs are characterized by having a transparent skin that allows one to see the internal organs. This individual is from Caimito, Esmeralda province. The photograph is part of the book “Sapos” (puce.edu.ec/zoologia/sron/sapos/index.html)”

Reticulated Glass Frog - Hyalinobatrachium valerioi

In the Reticulated Glass Frog, Hyalinobatrachium valerioi (Centrolenidae), a species with well studied parental care, males perform nocturnal brooding by adopting a posture in which ventral surface and thighs are in close contact with the clutch. It is thought that this behavior has a moistening function.

Reference: [1]

Photo credit: ©Michele Monari | Location: not indicated (2010)

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Tadpole of the Yellow dotted glass frog by Santiago Ron

“This Hyalinobatrachium aureoguttatum tadpole has arms and legs and is almost ready to metamorphose into a frog. This individual is from Caimito, Esmeraldas Province, Ecuador.

 The photograph is part of the book “Sapos” www.puce.edu.ec/zoologia/sron/sapos/index.html.“

Fleischmann’s Glass Frog - Hyalinobatrachium fleischmanni 

Hyalinobatrachium fleischmanni (Centrolenidae) is a small glass frog with males up to 25.5 mm and females reaching up to 32 mm. This species occurs from Guerrero and Veracruz in southern Mexico, south through Central America to Colombia.

References: [1] - [2]

Photo credit: ©Alex Vargas | Locality: Costa Rica (2013)

Glassy Fathers Do Matter: Egg Attendance Enhances Embryonic Survivorship in the Glass Frog Hyalinobatrachium valerioi

Hyalinobatrachium valerioi (Centrolenidae) is better known by names such as Reticulated Glass Frog, Valerio’s Glass Frog, La Palma Glass Frog, or Ranita de Vidrio [1].

This species ranges from central Costa Rica, through Panama and the Pacific lowlands of western Colombia, south to Mata Real in Azuay Province in Ecuador. It has also been reported from the Department of Caldas in the middle Magdalena Valley, Colombia [2]. 

Hyalinobatrachium valerioi is a tiny frog, with adult males ranging from 19.5 to 24.0 mm, and adult females measuring from 22.5 to 26 mm. 

The Reticulated Glass Frog is nocturnal. Males are highly territorial, maintaining territorial spacing by calls. If another male enters the territory, a call consisting of a squeak is made, sometimes by both the defending and the intruding male. If the intruder fails to leave immediately, wrestling occurs and the defending resident male will pin the intruding male down.

After mating, the female lays eggs in a sticky jelly mass consisting of a single layer of about 35 eggs, on the underside of a leaf above a stream. The egg deposition site may be up to 6 m above the water [1].

Males of the glass frog Hyalinobatrachium valerioi engage in diurnal and nocturnal attendance of egg clutches. The main cause of mortality in eggs is due to arthropod predation and desiccation of clutches [3].

To study the effect of parental care on embryonic survivorship, Vockenhuber et al. (2009) conducted a male removal experiment and measured embryonic survival rates on day 4, 8, and 12 after oviposition in attended and unattended clutches. With this study, they found that:

  • Clutch attendance was exclusively performed by males. During the night, attending males commonly engaged in brooding behavior by placing the ventral part of the body and thighs in close contact with the clutch. 
  • Embryonic survivorship was significantly higher in attended control clutches than in male-deprived clutches. Desiccation of clutches only occurred in unattended clutches, and arthropod predation was high in both groups.

Such results show that egg attendance in the glass frog H. valerioi enhances clutch survival to late prehatching stages and, therefore, can be considered as parental care, by deterring egg predators and preventing desiccation.

Although parental care yields benefits to male fitness via a lowered embryonic mortality, costs may be incurred in the form of lost mating opportunities, higher risk of adult predation, or energetic costs resulting from reduced feeding. However, males of H. valerioi, as with males of other frog species, continue to call during egg attendance and often accumulate multiple clutches.

[Download here the complete study]

 Photo credit: ©Brian Kubicki | Hyalinobatrachium valerioi from Costa Rica.

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