Western Pond Turtle
Emys marmorata
![[Western Pond Turtle]](/images/8ds.jpg)
Description
Physical
Our only native turtle species, it is a medium sized turtle that rarely exceeds 20 centimeters (8 inches) in length. The carapace does not arch as much as many other species. Face more blunt shaped than many other species.
Color and Pattern
Olive or brown above usually with lines and dashes radiating from the center of the carapace shields. Plastron shields yellow, young specimens often have a dark blotch at center of plastron. Head and limbs are typically olive with black spots.
Sexual Dimorphism
Males typically have a lighter throat and flatter shell than females, and longer rear claws.
Habitat
Primarily a pond turtle, it also inhabits pools in slower moving streams. Generally avoids large lakes and rapid moving water. Aquatic vegetation is necessary, likes to bask on logs. Females need suitable habitat away from the pond where they can dig nests and deposit their eggs. Some ponds that are boxed in by roads and concrete still support turtles, but successful breeding is rare at those locations.
Diet
Pond turtles feed on a variety of insects, small amphibians and fish, and aquatic vegetation.
Distribution Range
General range map taken from CWHR.
Museum records taken from following institutions: MVZ Herps, NMNH VZHerps.
Found throughout most of Shasta County. Absent from much of the south eastern portion.
Typical Elevation
We do not yet have enough records from distinct localities to calculate typical elevation. We need 18 more distinct localities.
Reproduction and Young
Females often leave the water and travel some distance to deposit their eggs. Lays 3 to 14 eggs from April to August (Stebbins 2003 pg 250). Young have yellow pigment on legs and head.
Taxonomy
The Western Pond Turtle (Emys marmorata) was originally described in 1852 by Baird and Girard as Emys marmorata.
The subspecies that occurs in our area traditionally is the Northwestern Pond Turtle (Emys marmorata marmorata). However, some do not currently recognize any subspecies.
Pronunciation
The assumed IPA pronunciation of this species: /ˈɛm is/ /mɑr mɔr ˈɑ tɔ/
Taxonomic Etymology
Emys is from the Greek ??? and means freshwater turtle (Beltz 2006).
marmorata is from the Latin marmor which means marble. It is a reference to the marbled appearance of the carapace pattern (Beltz 2006).
Taxonomy Notes
In 1862 this species was placed in the genus Clemmys (Strauch, Ref. Needed). It stayed there for a long time, Clemmys marmorata is the taxonomy used in a lot of literature. However, it does not seem to belong there.
Within the family Emydidae four currently described extant species make up the clade Emys:
- European Pond Turtle (Emys orbicularis) - type species for genus Emys
- Sicilian Pond turtle (Emys trinacris)
- Western Pond turtle (Emys [=Clemmys,Actinemys] marmorata)
- Blanding’s Turtle (Emys [=Emydoidea] blandingii)
The Spotted Turtle (Clemmys guttata), which is the type species for genus Clemmys, is not part of this clade. Thus the Western Pond Turtle does not belong in the genus Clemmys.
Within the Emys complex, taxonomy is a bit confusing. The two European species are undisputably very closely related. When looking at the mitochondrial phylogeny, the Western Pond Turtle appears to be monophyletic with Blanding’s Turtle to the exclusion of the two European species. However when looking at nuclear phylogeny, Blanding’s Turtle appears to be monophyletic with the two European species to the exclusion of the Western Pond Turtle (Spinks and Shaffer 2009 Abstract).
As if that does not complicate things enough, morphological differences also come into play. The two European species and Blanding’s Turtle have hinged plastra while the Western Pond Turtle does not (Spinks and Shaffer 2009 pg 2).
There are two schools of thought with respect to the Emys complex. In Holman and Fritz 2001 the close relationship between the members of the clade is recognized, but they argued for placing the Western Pond Turtle into its own monophylic genus Actinemys rather than Emys or Emydoidea to avoid a genus that contained both hinged and unhinged species (pg 323). They did not address taxonomic rearrangement for Blanding’s Turtle, keeping it in the genus Emydoidea.
This is the school of thought currently followed by the SSAR (Crother 2008) resulting in the taxon Actinemys marmorata for the Western Pond Turtle and is currently used in some literature.
The second school of thought put forth in Spinks and Shaffer 2009 notes the morphologic difference with plastral kinesis (pg 2) but does not place such emphasis on the impact of that morphological difference on proper taxonomy. Rather, it addresses the apparent conflict between mtDNA and nuDNA trees within the complex. They hypothesize that Blanding’s Turtle is a sister taxon the the European Emys. After the nuDNA split with the European Emys, a second warming period allowed secondary contact between Blanding’s Turtle and the Western Pond Turtle resulting in hybridization and intogression between the two populations, allowing for Western Pond Turtles to capture Blanding’s mtDNA. They then argue that using three different genera for the member species of this complex obscures the phylogenetic relationship and biogeographical history of the complex, suggesting that they all be placed in the genus Emys. Of interesting note, that is the genus used in the original description for each species of the complex.
Under this hypothesis, Actinemys and Emydoidea become junior synonyms of Emys. This is the school of thought currently followed by the CNAH and is the relationship hypothesis for the complex that I personally prefer.
Additional Information
Images
Unless otherwise noted, all images are of wild specimens in Shasta County.
Please be kind, do not hotlink images and do not use images without permission of the copyright owner.
![[Western Pond Turtle]](/images/8sm.jpg)
![[Western Pond Turtle]](/images/9sm.jpg)
©Michael A. Peters
The larger turtle is the Western Pond Turtle. The smaller turtle is a Pond Slider. Redding, CA
![[Western Pond Turtle]](/images/82sm.jpg)
©Michael A. Peters
The Western Pond Turtle is on the left. A Pond Slider is on the right. Note the different carapace shape. Pond adjacent to the Sacramento River Trail near the Sun Dial Bridge. Redding, CA
Habitat Shots
Unless otherwise noted, these habitat shots are from within Shasta County where this species is known to occur.
![[Western Pond Turtle habitat]](/images/66sm.jpg)
Species of Special Concern
This species is listed as a Species of Special Concern by the State of California Department of Fish & Game.
If you come across this species, please note that it may be a violation of state law to collect it or even touch it. Federal laws may also apply.
If you can, please do the following:
- Accurately record the location where the animal was found. The best way to do this is with a GPS device.
- Photograph the specimen. Take as many photographs as you can without causing too much stress to the animal.
- Take note of the habitat and its condition. Photographs are good for this, but do not always tell the entire story.
- Take note on any possible threats to the population. For example, if it is one of our threatened native frog species, is there an American Bullfrog population in the immediate vicinity? Are you aware of an American Bullfrog population in a nearby aquatic system? What about erosion? Introduced trout?
- Report the sighting to the California Natural Diversity Database.
It takes a little effort to file a report, but your report may help the necessary agencies protect that population. It is difficult for them to protect populations they do not know about or populations they think are extirpated. Even species of special concern that are currently doing well in Shasta County should be reported. When population declines happen, they tend to happen very fast. Reports of specific localities where a species is known to have occured may help researchers determine survey sites if our population of one of these species does crash.
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