Pituophis melanoleucus (gopher, bull, and pinesnake) is among the most widely di
ID: 65096 • Letter: P
Question
Pituophis melanoleucus (gopher, bull, and pinesnake) is among the most widely distributed polytypic species complexes in North America, with most authors recognizing from a single transcontinental species (the melanoleucus complex, composed of 15 subspecies) to four (monotypic and polytypic) species. We used mitochondrial gene sequences from the two middle American species, P. deppei and P. lineaticollis, and from 13 subspecies from most of the range of the melanoleucus complex to test various phylogenetic hypotheses for Pituophis.
FIG. 1. Approximate distribution of the subspecies of the Pituophis melanoleucus complex in Canada, the United States, and Mexico (after Conant and Collins, 1991; Reichling, 1995; Stebbins, 1985; Sweet and Parker, 1990; Tennant, 1984). Numbers indicate the approximate localities of the specimens included in this study. The black bar across central Baja California indicates the inferred location of the hypothesized Pleistocene midpeninsular seaway (after Upton and Murphy, 1997). The four islands indicated with arrows are not drawn to scale.
1. How many species of snake are represented in these pictures (1 – 6 )? Use morphological characteristics to group these snakes into species. _______
FIG. 6. Maximum likelihood tree (LnL5 25539.18903) for 42 mtDNA haplotypes of Pituophis. Branche lengths are proportional to amount of DNA sequence change estimated by the maximum likelihood algorithm. The proposed specific taxonomy is indicated for each taxon.
Discussion questions.
2. Compare species pictures and geographic ranges to this molecular tree. How many species are present in this tree?
3. Pituophis ruthveni is highly endangered. Does knowing this population/species is endangered make a difference in how you delineate species?
4. Examine the clade containing P. vertebralis and P. biramus. Suppose your laboratory experimentation showed that P. vertebralis and P. biramus do not produce viable offspring. If you are using the Biological SC to delineate species how many species would you identify in this clas? What if you were using the Phylogenetic SC/ evolutionary SC/ or unified SC? How many species would you identify then?
5. The authors of this study commented that “We therefore recognize three distinct species in the melanoleucus complex, P. melanoleucus (sensu stricto), P. catenifer, and P. ruthveni; whether additional species should be recognized within P. catenifer remains questionable.” Do you agree with their species delineation? How many species should be recognized in P. catinifer?
6. What additional data might we use to start answering this question of # of species in P. catinifer?
Explanation / Answer
As in the content of the Q. it is talked about some figures, but not mentioned, so it would be better to mention the figure so that the Q could be answered exactly.