1. 엔사티나 에슈솔치 Ensatina eschscholtzii
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아종 Subspecies
* Ensatina : L. ensatus "sword shaped" and L. -ina "similar to" — poss. ref. to the teeth
(참고) L. sensis "sword (검 劍, 군도 軍刀, 긴 칼)"
* croceater : L. croceus "saffron colored" (짙은 황금색의) and L. -ater "black" — ref. color pattern
* eschscholtzii : honors Johann F. Eschscholtz
* klauberi : honors Laurence M. Klauber
* oregonensis : belonging to the state of Oregon — ref. distribution
* picta : L. picta "painted or embroidered" — ref. bright dorsal coloration painted
* platensis : belonging to the Rio La Plata, Uruguay — Espada named this salamander Urotropis platensis because he thought it came from Montevideo, Uruguay
* xanthoptica : Gr. xanthos "yellow" and Gr. ops "eye" and Gr. -ika "belonging to" — ref. eye color
(범례) GR = Greek ; L.= Latin ; ref. = refers to/reference to ; poss. = possible
2. 도롱뇽의 이야기 The Salamander's Tale
Names are a menace in evolutionary history. It is no secret that palaeontology is a controversial subject in which there are even some personal enmities. At least eight books called Bones of Contention are in print. And if you look at what two palaeontologists are quarrelling about, as often as not it turns out to be a name. Is this fossil Homo erectus, or is it an archaic Homo sapiens ? Is this one an early Homo habilis or a late Australopithecus ? People evidently feel strongly about such questions, but they often turn out to be splitting hairs. Indeed, they resemble theological questions, which I suppose gives a clue to why they arouse such passionate disagreements. The obsession with discrete names is an example of what I call the tyranny of the discontinuous mind. The Salamander's Tale strikes a blow against the discontinuous mind.
The Central Valley runs much of the length of California, bounded by the Coastal Range to the west and by the Sierra Nevada to the east. These long mountain ranges link up at the north and the south ends of the valley, which is therefore surrounded by high ground. Throughout this high ground lives a genus of salamanders called Ensatina . The Central Valley itself, about 40 miles wide, is not friendly to salamanders, and they are not found there. They can move all round the valley but normally not across it, in an elongated ring of more or less continuous population. In practice any one salamander's short legs in its short lifetime don't carry it far from its birthplace. But genes, persisting through a longer timescale, are another matter. Individual salamanders can interbreed with neighbours whose parents may have interbred with neighbours further round the ring, and so on. There is therefore potentially gene flow all around the ring. Potentially. What happens in practice has been elegantly worked out by the research of my old colleagues at the University of California at Berkeley, initiated by Robert Stebbins and continued by David Wake.
In a study area called Camp Wolahi, in the mountains to the south of the valley, there are two clearly distinct species of Ensatina which do not interbreed. One is conspicuously marked with yellow and black blotches. The other is a uniform light brown with no blotches. Camp Wolahi is in a zone of overlap, but wider sampling shows that the blotched species is typical of the eastern side of the Central Valley which, here in Southern California, is known as the San Joaquin Valley (pronounced San Wahkeen). The light brown species, on the contrary, is typically found on the western side of the San Joaquin. Non-interbreeding is the recognised criterion for whether two populations deserve distinct species names. It therefore should be straightforward to use the name Ensatina eschscholtzii for the plain western species, and Ensatina klauberi for the blotched eastern species — straightforward but for one remarkable circumstance, which is the nub of the tale.
If you go up to the mountains that bound the north end of the Central Valley, which up there is called the Sacramento Valley, you'll find only one species of Ensatina . Its appearance is intermediate between the blotched and the plain species: mostly brown, with rather indistinct blotches. It is not a hybrid between the two: that is the wrong way to look at it. To discover the right way, make two expeditions south, sampling the salamander populations as they fork to west and east on either side of the Central Valley. On the east side, they become progressively more blotched until they reach the extreme of klauberi in the far south. On the west side, the salamanders become progressively more like the plain eschscholtzii that we met in the zone of overlap at Camp Wolahi.
This is why it is hard to treat Ensatina eschscholtzii and Ensatina klauberi with confidence as separate species. They are a ‘ring species’. You'll recognise them as separate species if you only sample in the south. Move north, however, and they gradually turn into each other. Zoologists normally follow Stebbins's lead and place them all in the same species, Ensatina eschscholtzii, but give them a range of subspecies names. Starting in the far south with Ensatina eschscholtzii eschscholtzii, the plain brown form, we move up the west side of the valley through Ensatina eschscholtzii xanthoptica and Ensatina eschscholtzii oregonensis which, as its name suggests, is also found further north in Oregon and Washington. At the north end of California's Central Valley is Ensatina eschscholtzii picta, the semi-blotched form mentioned before. Moving on round the ring and down the east side of the valley, we pass through Ensatina eschscholtzii platensis which is a bit more blotched than picta, then Ensatina eschscholtzii croceater until we reach Ensatina eschscholtzii klauberi (which is the very blotched one that we previously called Ensatina klauberi when we were considering it to be a separate species).
Stebbins believes that the ancestors of Ensatina arrived at the north end of the Central Valley and evolved gradually down the two sides of the valley, diverging as they went. An alternative possibility is that they started in the south as, say, Ensatina eschscholtzii eschscholtzii, then evolved their way up the west side of the valley, round the top and down the other side, ending up as Ensatina eschscholtzii klauberi at the other end of the ring. Whatever the history, what happens today is that there is hybridization all round the ring, except where the two ends of the line meet, in the far south of California.
As a complication, it seems that the Central Valley is not a total barrier to gene flow. Occasionally, salamanders seem to have made it across, for there are populations of, for example, xanthoptica , one of the western subspecies, on the eastern side of the valley, where they hybridise with the eastern subspecies, platensis . Yet another complication is that there is a small break near the south end of the ring, where there seem to be no salamanders at all. Presumably they used to be there, but have died out. Or maybe they are still there but have not been found: I am told that the mountains in this area are rugged and hard to search. The ring is complicated, but a ring of continuous gene flow is, nevertheless, the predominant pattern in this genus, as it is with the better-known case of herring gulls and lesser black-backed gulls around the Arctic Circle.
- 도킨스,조상이야기, 336페이지-
아종 Subspecies
- Yellow Blotched Ensatina — E. e. croceater (Cope, 1868)
- Monterey Ensatina — E. e. eschscholtzii Gray, 1850
- Large Blotched Ensatina — E. e. klauberi Dunn, 1929
- Oregon Ensatina — E. e. oregonensis (Girard, 1856)
- Painted Ensatina — E. e. picta Wood, 1940
- Sierra Nevada Ensatina — E. e. platensis (Jiménez de la Espada, 1875)
- Yellow Eyed Ensatina — E. e. xanthoptica Stebbins, 1949
* Ensatina : L. ensatus "sword shaped" and L. -ina "similar to" — poss. ref. to the teeth
(참고) L. sensis "sword (검 劍, 군도 軍刀, 긴 칼)"
* croceater : L. croceus "saffron colored" (짙은 황금색의) and L. -ater "black" — ref. color pattern
* eschscholtzii : honors Johann F. Eschscholtz
* klauberi : honors Laurence M. Klauber
* oregonensis : belonging to the state of Oregon — ref. distribution
* picta : L. picta "painted or embroidered" — ref. bright dorsal coloration painted
* platensis : belonging to the Rio La Plata, Uruguay — Espada named this salamander Urotropis platensis because he thought it came from Montevideo, Uruguay
* xanthoptica : Gr. xanthos "yellow" and Gr. ops "eye" and Gr. -ika "belonging to" — ref. eye color
(범례) GR = Greek ; L.= Latin ; ref. = refers to/reference to ; poss. = possible
2. 도롱뇽의 이야기 The Salamander's Tale
Names are a menace in evolutionary history. It is no secret that palaeontology is a controversial subject in which there are even some personal enmities. At least eight books called Bones of Contention are in print. And if you look at what two palaeontologists are quarrelling about, as often as not it turns out to be a name. Is this fossil Homo erectus, or is it an archaic Homo sapiens ? Is this one an early Homo habilis or a late Australopithecus ? People evidently feel strongly about such questions, but they often turn out to be splitting hairs. Indeed, they resemble theological questions, which I suppose gives a clue to why they arouse such passionate disagreements. The obsession with discrete names is an example of what I call the tyranny of the discontinuous mind. The Salamander's Tale strikes a blow against the discontinuous mind.
The Central Valley runs much of the length of California, bounded by the Coastal Range to the west and by the Sierra Nevada to the east. These long mountain ranges link up at the north and the south ends of the valley, which is therefore surrounded by high ground. Throughout this high ground lives a genus of salamanders called Ensatina . The Central Valley itself, about 40 miles wide, is not friendly to salamanders, and they are not found there. They can move all round the valley but normally not across it, in an elongated ring of more or less continuous population. In practice any one salamander's short legs in its short lifetime don't carry it far from its birthplace. But genes, persisting through a longer timescale, are another matter. Individual salamanders can interbreed with neighbours whose parents may have interbred with neighbours further round the ring, and so on. There is therefore potentially gene flow all around the ring. Potentially. What happens in practice has been elegantly worked out by the research of my old colleagues at the University of California at Berkeley, initiated by Robert Stebbins and continued by David Wake.
In a study area called Camp Wolahi, in the mountains to the south of the valley, there are two clearly distinct species of Ensatina which do not interbreed. One is conspicuously marked with yellow and black blotches. The other is a uniform light brown with no blotches. Camp Wolahi is in a zone of overlap, but wider sampling shows that the blotched species is typical of the eastern side of the Central Valley which, here in Southern California, is known as the San Joaquin Valley (pronounced San Wahkeen). The light brown species, on the contrary, is typically found on the western side of the San Joaquin. Non-interbreeding is the recognised criterion for whether two populations deserve distinct species names. It therefore should be straightforward to use the name Ensatina eschscholtzii for the plain western species, and Ensatina klauberi for the blotched eastern species — straightforward but for one remarkable circumstance, which is the nub of the tale.
If you go up to the mountains that bound the north end of the Central Valley, which up there is called the Sacramento Valley, you'll find only one species of Ensatina . Its appearance is intermediate between the blotched and the plain species: mostly brown, with rather indistinct blotches. It is not a hybrid between the two: that is the wrong way to look at it. To discover the right way, make two expeditions south, sampling the salamander populations as they fork to west and east on either side of the Central Valley. On the east side, they become progressively more blotched until they reach the extreme of klauberi in the far south. On the west side, the salamanders become progressively more like the plain eschscholtzii that we met in the zone of overlap at Camp Wolahi.
This is why it is hard to treat Ensatina eschscholtzii and Ensatina klauberi with confidence as separate species. They are a ‘ring species’. You'll recognise them as separate species if you only sample in the south. Move north, however, and they gradually turn into each other. Zoologists normally follow Stebbins's lead and place them all in the same species, Ensatina eschscholtzii, but give them a range of subspecies names. Starting in the far south with Ensatina eschscholtzii eschscholtzii, the plain brown form, we move up the west side of the valley through Ensatina eschscholtzii xanthoptica and Ensatina eschscholtzii oregonensis which, as its name suggests, is also found further north in Oregon and Washington. At the north end of California's Central Valley is Ensatina eschscholtzii picta, the semi-blotched form mentioned before. Moving on round the ring and down the east side of the valley, we pass through Ensatina eschscholtzii platensis which is a bit more blotched than picta, then Ensatina eschscholtzii croceater until we reach Ensatina eschscholtzii klauberi (which is the very blotched one that we previously called Ensatina klauberi when we were considering it to be a separate species).
Stebbins believes that the ancestors of Ensatina arrived at the north end of the Central Valley and evolved gradually down the two sides of the valley, diverging as they went. An alternative possibility is that they started in the south as, say, Ensatina eschscholtzii eschscholtzii, then evolved their way up the west side of the valley, round the top and down the other side, ending up as Ensatina eschscholtzii klauberi at the other end of the ring. Whatever the history, what happens today is that there is hybridization all round the ring, except where the two ends of the line meet, in the far south of California.
As a complication, it seems that the Central Valley is not a total barrier to gene flow. Occasionally, salamanders seem to have made it across, for there are populations of, for example, xanthoptica , one of the western subspecies, on the eastern side of the valley, where they hybridise with the eastern subspecies, platensis . Yet another complication is that there is a small break near the south end of the ring, where there seem to be no salamanders at all. Presumably they used to be there, but have died out. Or maybe they are still there but have not been found: I am told that the mountains in this area are rugged and hard to search. The ring is complicated, but a ring of continuous gene flow is, nevertheless, the predominant pattern in this genus, as it is with the better-known case of herring gulls and lesser black-backed gulls around the Arctic Circle.
3. 보충 자료
Ensatina phylogeny based on mitochondrial DNA. Notice that oregonensis is composed of four separate evolutionary lineages, which happen to be morphologically similar to one another. Similarly, platensis is made up of two distinct lineages. In this case, Ensatina's DNA reveals distinct evolutionary histories that morphology alone did not.
4. 참고
엔사티나
http://en.wikipedia.org/wiki/Ensatina
센트럴 밸리
http://en.wikipedia.org/wiki/Central_Valley_(California)
샌와킨 계곡
http://en.wikipedia.org/wiki/San_Joaquin_Valley
새크라멘토 계곡
http://en.wikipedia.org/wiki/Sacramento_Valley
Johann F. Eschscholtz
http://en.wikipedia.org/wiki/Johann_Friedrich_von_Eschscholtz
Laurence M. Klauber
http://en.wikipedia.org/wiki/Laurence_Monroe_Klauber
Camp Wolahi
a privatley held enclave in Rancho Cuyamaca State Park, Sandiego County.
Camp Wolahi, operated by the Campfire Girls, is located on the south side of Bouder Creek, along the north-facing slopes of Middle Peak(5,893 ft. elev.), 1 kim to the south.
위치
http://www.lat-long.com/Latitude-Longitude-270232-California-Camp_Wolahi.html
Rancho Cuyamaca State Park
http://en.wikipedia.org/wiki/Cuyamaca_Rancho_State_Park
the University of California Museum of Paleontology
http://evolution.berkeley.edu/
California Salamanders
http://www.californiaherps.com/salamanders/salamanderspics.html
