Caecilians: Species

Summary: This little known amphibian has 200 different species in its ranks. Join Kiersten as she takes you on a quick tour of the different caecilian species.

 

 For my hearing impaired listeners, a complete transcript of this podcast follows the show notes on Podbean.

 

Show Notes:

The Amphibian Class by Rebecca Stefoff

https://www.britannica.com/animal/caecilian-amphibian/classification

 

Music written and performed by Katherine Camp

 

Transcript

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Kiersten - This is Ten Things I Like About…a ten minute, ten episode podcast about unknown or misunderstood wildlife.

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Welcome to Ten Things I Like About… I’m Kiersten, your host, and this is a podcast about misunderstood or unknown creatures in nature. Some we’ll find right out side our doors and some are continents away but all are fascinating. 

This podcast will focus ten, ten minute episodes on different animals and their amazing characteristics. Please join me on this extraordinary journey, you won’t regret it.

This episode continues caecilians and the fourth thing I like about this unknown animal is the number of species that we know about.

I have to admit as I was doing my research into the caecilian I was amazed to discover that we actually know of about 200 species of this amphibian. Most of my friends and family looked at me with blank faces when I mentioned that I wanted to do the next series of Ten Things I Like About on caecilians. I had a few people ask me if it was going to be about people from Sicily. (laughs) Clearly not.

This episode will include a lot of scientific names so I apologize in advance but most caecilians don’t have common names since they are not very well known. 

Let’s start off with a little taxonomy, that’s the scientific classification of all living things. All caecilians are in Kingdom Animalia, as are humans, Phylum Chordata, because they are vertebrates with a skeletal system, Class Amphibia, because they are amphibians, Subclass Lissamphibia, and Order Gymnophiona also known as Apoda which is Latin for “without foot”. Within this Order there are ten Families of caecilians.

The different Families of caecilians are distinguished from each other based on physical characteristics and life history. The extant, or living species, are classified by the absence or presence of a tail, the amount of fusion of the skull bones, the degree of movement in the skull, the nature of the annular grooves (these are the cutaneous grooves that circle the body), and the structure of the phallodeum (which is the male’s sex organ). Classification is also based on whether an aquatic larval stage is present in the life history of the caecilian and whether they lay eggs or have live birth.

The youngest family of caecilians is Family Caeciliidae. The species in this family date from the Paleocene era which is 65 to 55 million years ago to today. They have no tails and most have no aquatic larval stage. There are 42 species in Family Caeciliidae. They are native to Central and South America and as adults they range in size from 4 to 60 inches.

The next seven families all date from the Cretaceous period which is 145 to 65 million years ago to today.

Family Dermophiidae includes 13 species. They have secondary annuli with annular scales. They are viviparous which means they give live birth and they are found in Africa and Central and South America.

Family Herpelidae, commonly known as the African caecilians, is native to Africa and includes 9 species of caecilian.

Family Ichthyophiidae species have tails, an aquatic larval stage and are native to Southeast Asia, peninsular India, Sri Lanka, Sumatra, Borneo, and the Philippines. There are 50 species in this family that range in size from 16 to 20 inches as adults. This family is also known as the Asiatic tailed caecilians or the fish caecilians. I couldn’t  determine why they are called fish caecilians but they do have an aquatic larval stage. 

Family Indotyphlidae is native to Africa, the Seychelles, and India. There are 21 speices in this family. Some of them are viviparous and some of them are oviparous which means they lay eggs to reproduce. The viviparous species do not have scales or secondary annuli. The characteristics that bond these species together are their non-perforated ear bone and the presence of teeth in the lower jaw.

Family Rhinatrematidae has tails and aquatic larvae. The 11 species of this family are native to South America and range in size from 10 to 13 inches as adults. This family is also known as the Neotropical tailed caecilians, the American tailed caecilians, or the beaked caecilians. 

Family Siphonopidae, also known as common caecilians, have non-perforated ear bones and no teeth in the lower jaw. The 19 species of this South American caecilian family are oviparous. 

Our last family originating in the Cretaceous period is Family Typhlonectidae. These caecilians have no tails. Adults are aquatic, so these caecilians live their entire lives in the water. The young have gills but the adults breathe through tracheal lungs. There are 13 species in this family and adults range in size from 20 to 28 inches. Family Typhlonectidae is native to South America and are also known as rubber eels. 

Our last two families are our two oldest species and originate in the Jurassic period which is 200 to 145 million years ago. 

Family Scolecomorphidae is native to Africa and only contains 6 species. They have no tail and no aquatic larval stage. Adults range in size from 16 to 18 inches. They are also known as tropical caecilians, the buried-eyed caecilians, or the African caecilians. 

Family Chikilidae is the most recently discovered family but they are one of the two oldest living caecilians. The seven species of this family have two rows of teeth on their lower jaw and are native to northeastern India. The year 2012 brought this terrestrial caecilian into the light and is named after chikila, the northeastern Indian tribal name for this amphibian. 

Now that we’ve talked a bit about the different families of caecilians let’s talk about colors! In the anatomy episode we learned that all capelins essentially look like earthworms, They have no legs, they have annuli that make their skin look segmented, and they are covered in slimy mucus. But we didn’t discuss what colors they come in. Yes! I said colors. 

Many caecilians, actually a lot of caecilians, are a gray to black color, but not all. Some caecilians are blue, some are red or orange, some have accentuated annuli that gives them a two-toned ringed appearance. Some even have bright yellow striping that runs from their head to their tails! Considering all caecilians are blind and live in mostly dark places, we’re not entirely sure why they have different colors, but boy are they pretty. 

Siphonops annulatus is a beautiful azure blue color, the sticky caecilian is dark gray with a yellow stripe down the midline of their body, the Sao Tome caecilian is bright yellow all over, the Panamanian caecilian is lime green! With 200 different species their color possibilities are quite varied.

They vary drastically in size as well. The largest caecilian is Caecilia thompsoni and this species measures in at a whopping 5 feet long! Holy Smokes! They can weigh up to 2.2 lbs. If you’d live to get a chance to see this caecilian plan a visit to Columbia, as this is their native country. 

The smallest caecilian is a tie between Idiocranium russeli from West Africa and Grandisonia brevis, from the Seychelles. These two species grow to only 4 inches. That is quite a difference in size! Boy caecilians sure as fascinating.

Well that’s it for caecilian species, try saying that five times fast, and I know you had a great time with this episode because it’s my fourth favorite thing about caecilians.  

 

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Join me next week for another thing I like about caecilians!

 

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This has been an episode of Ten Things I like About with Kiersten and Company. Original music written and performed by Katherine Camp, piano extraordinaire.