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Cervino, N. G., Elias-Costa, A. J., Pereyra, M. O., & Faivovich, J. (2021). A closer look at pupil diversity and evolution in frogs and toads. Proceedings of the Royal Society B, 288(1957), 20211402.

Rachel Keeffe, David C Blackburn, Comparative morphology of the humerus in forward-burrowing frogs, Biological Journal of the Linnean Society, Volume 131, Issue 2, October 2020, Pages 291–303, https://doi.org/10.1093/biolinnean/blaa092

Rong, Y. F., Vasilyan, D., Dong, L. P., & Wang, Y. (2021). Revision of Chunerpeton tianyiense (Lissamphibia, Caudata): is it a cryptobranchid salamander?. Palaeoworld, 30(4), 708-723.

Rosset, S. D., Fadel, R. M., da Silva Guimarães, C., Carvalho, P. S., Ceron, K., Pedrozo, M., ... & Mângia, S. (2021). A New Burrowing Frog of the Odontophrynus americanus Species Group (Anura, Odontophrynidae) from Subtropical Regions of Argentina, Brazil, and Paraguay. Ichthyology & Herpetology, 109(1), 228-244.

Thurman, L. L., Cousins, C. D., Button, S. T., Garcia, T. S., Henderson, A. L., Olson, D. H., & Piovia-Scott, J. (2021). Treading Water: Conservation of Headwater-Stream

YOSHIDA, S., & MEKADA, K. Histological observation of the external gills of a Mexican axolotl (Ambystoma mexicanum) with atypical blood vessels.

Cervino, N. G., Elias-Costa, A. J., Pereyra, M. O., & Faivovich, J. (2021). A closer look at pupil diversity and evolution in frogs and toads. Proceedings of the Royal Society B, 288(1957), 20211402.

links:

http://pierce.wesleyancollege.edu/faculty/brhoades/courses/bio270manual/lab5.html

https://animals.sandiegozoo.org/animals/chinese-giant-salamander

https://www.nationalgeographic.com/animals/article/131220-hellbender-salamander-conservation-endangered-animals-science

https://kids.nationalgeographic.com/animals/amphibians/facts/mexican-axolotl

https://blogs.scientificamerican.com/tetrapod-zoology/the-biology-of-sirens/

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NAME: hellbender (Cryptobranchus allegeniensis)

DESCRIPTION: The third largest salamander and reaches a length of 30 cm. Its numerous teeth are small, bicuspid, and arranged in single rows.

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NAME: Sirens (Sirendae)

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NAME: Chinese giant salamander (Andrias davidianus)

DESCRIPTION: he largest salamander and can reach a length of up to 180 cm. Similar to the hellbender, it has numerous small teeth arranged in single rows in the upper and lower jaws.

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NAME: Mexican axolotl (Ambystoma mexicanum)

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Rong, Y. F., Vasilyan, D., Dong, L. P., & Wang, Y. (2021). Revision of Chunerpeton tianyiense (Lissamphibia, Caudata): is it a cryptobranchid salamander?. Palae

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Giant branch of salamanders

A study shows a fossil that has been preserved in northeastern china of crown salamanders. which is correlated to the family Cryptobranchidae, the world’s largest known extant caudate.

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Source: YOSHIDA, S., & MEKADA, K. Histological observation of the external gills of a Mexican axolotl (Ambystoma mexicanum) with atypical blood vessels.

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Presence of external gills

According to a study by Yoshida and Mekada in 2019,  which talks about how salamanders have normal external gill filaments and atypical external gill filaments.

Specifically Mexican axolotl (Ambystoma mexicanum) with unusual atypical blood vessels.

Such external gills had an elliptical shape and a periphery covered with layers of epithelial cells within its tissues which have arterioles in its end section.

the study stated that “external gills of the focal axolotl was composed of three lobes of different lengths, the back of which were irregularly covered with a dense growth of gill filaments”

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Description:

The attached picture is the illustrated external anatomy of Frogs. This evolutionary analysis and comparative analysis will focus on the presence of external gills, and the giant branch of salamanders.

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DESCRIPTION: Evolution of the pupil shape in frogs and toads (Anura). ACSR using the phylogenetic hypothesis of Jetz & Pyron

SOURCE: Jetz W, Pyron RA. 2018The interplay of past diversification and evolutionary isolation with present imperilment across the amphibian tree of life. Nat. Ecol. Evol. 2, 850-858. (doi:10.1038/s41559-018-0515-5) Crossref, PubMed, ISI, Google Scholar

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VERTICAL

Species 1
Name: Agalychnis callidryas (Hylidae)

Species 2
Name: Afrixalus fornasini (Hyperoliidae

HORIZONTAL

Species 1
Name: Sphaenorhynchus lacteus (Hylidae)

Species 2
Name: Espadarana durrellorum (Centrolenidae

TRIANGULAR

Species 1
Name: Crinia sloanei (Myobatrachidae)

Species 2
Name: Bombina variegata (Bombinatoridae)

RHOMBOIDAL

Species 1
Name: Nyctibatrachus karnatakaensis (Nyctibatrachidae)

Species 2
Name: Odontophrynus americanus (Odontophrynidae)

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Pupil shape which shows a rhombus-like structure.

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Pupil shape which shows a pyramid-like structure.

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A persistent pupil shape in neobatrachians, regardless of whether it evolved independently in two of its major clades, Natatanura and Nobleobatrachia, or not.

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Homologous in all early-diverging anuran clades that have this pupil shape: Ascaphidae + Leiopelmatidae, Alytidae, Xenoanura, Anomocoela, and Heleophrynidae (with some internal transformations in these clades).

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Source: Cervino, N. G., Elias-Costa, A. J., Pereyra, M. O., & Faivovich, J. (2021). A closer look at pupil diversity and evolution in frogs and toads. Proceedin

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Pupil Density: there is multiple pupil morphology that can be studied within the order of anuran. such pupil shapes are the following:

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NAME: Scaphiopus holbrookii (Scaphiopodidae)

DESCRIPTION: brown in color, with yellowish stripes on its back.It has one spur on each of its back feet for burrowing.

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NAME: Notaden bennettii (Myobatrachidae)

DESCRIPTION: yellow or greenish Australian myobatrachid. Usually resides in dry regions and lives underground, emerging from its burrow after heavy rain.

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NAME: Hemisus perreti (Hemisotidae)

DESCRIPTION: Slippery frog

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NAME: Myobatrachus gouldii (Myobatrachidae)

DESCRIPTION: a small head, short limbs, and a round body.

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Burrowing can be directly connected to the Frog’s external body appearance, usually, frogs with a backward burrow have a larger and spherical belly which causes them to have a larger trunk. backward burrowing frogs also have swollen-like forelimb and hindlimb which makes them look like they’re in a sitting position (Stepanova & Womack, 2020).

Such species use their hindlimbs to dig into the soil and generally have keratinized spades on the foot covering the prehallux. and dig forwards into the substrate with their forelimbs (e.g. Alytes and Pseudacris) and, in some cases, use their pointed heads to penetrate into the ground.

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Frogs with a backward burrowing have a leaning position, some backward burrowing frogs have swollen-like forelimb, too, but most of them have a normal-sized forelimb and hindlimb (Citadini et al., 2018).

Have typically small eyes, robust postcranial skeleton, and a pointed reinforced rostrum.

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Source: T. Pierson (A, C), J. Rowley (B), S. Mahony (D), G. Jongsma (E) and, P. Peloso (F).

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Burrowing: is one of the many locomotor movements of frogs which is categorized into two types. which is the forward burrowing, the rare movement amongst the species of frogs, and the backward burrowing, which we usually can observe on frogs.

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Description:

The attached picture is the illustrated external anatomy of Frogs. This evolutionary analysis and comparative analysis will focus on the External Burrowing of frogs, and its pupil morphology.