Mitochondrial Dna Sequence Data Indicate Evidence For Multiple Species Within Peromyscus Maniculatus Author Bradley, Robert D. Department of Biological Sciences and the Museum Texas Tech University Lubbock, TX 79409 - 3131 robert.bradley@ttu.edu Author Francis, James Q. Department of Biological Sciences Texas Tech University Lubbock, TX 79409 - 3131 Author Platt II, Roy N. Department of Biological Sciences Texas Tech University Lubbock, TX 79409 - 3131 neal.platt@gmail.com Author Soniat, Taylor J. Department of Biological Sciences Texas Tech University Lubbock, TX 79409 - 3131 taylor.soniat@ttu.edu Author Alvarez, Daysi Author Lindsey, Laramie L. Department of Biological Sciences Texas Tech University Lubbock, TX 79409 - 3131 laramie.lindsey@ttu.edu text Special Publications of the Museum of Texas Tech University 2019 2019-10-10 70 1 59 journal article http://doi.org/10.5281/zenodo.7221903 19390c14-db95-4117-a068-a097ab5fab4d 7221903 Peromyscus sejugis Burt 1932 Peromyscus sejugis Burt, 1932:171 . Holotype .— California Institute of Technology (catalog number 50,632); adult male ; skin and skull. Original number W. H. Burt 3,530 . Type locality.— Mexico : Baja California Sur ; Santa Cruz Island , 25º 17’N , 110º 43’W ; collected 23 January 1932 . Subspecies.— P . sejugis is monotypic. Diagnosis.— Color of upperparts grayish with avellaneous and underparts white; tail bicolored with a narrow dorsal stripe. Skull arched antero-posteriorly; rostrum heavy; nasals broad, tapering posteriorly; relatively small auditory bullae ( Burt 1932 ). Average measurements ( Álvarez-Castañeda 2001 ): 160–197 mm ; (= 184 mm ) and a tail length that ranged between 65–94 mm ; (= 85 mm ). Larger in size than forms occurring on the mainland (specimens now assigned to P . gambelii ), especially in total length ( 184 mm versus 164 mm ) and tail length ( 85 mm versus 75 mm ). Distribution.— Known only from the Santa Cruz and San Diego Islands, Gulf of California, Mexico. Comparisons.— A member of the P. maniculatus species group. Burt (1932) associated P. sejugis with P. maniculatus and noted that it was larger in size compared to P. m. cooledgei (now P . gambelii ). The association with P . gambelii was confirmed based on phallic and allozyme data ( Hooper and Musser 1964 ; Avise et al. 1979 ). Avise et al. (1979) implied that P. sejugis is as different from P. maniculatus (now P . gambelii ) as it is from P. melanotis and P. polionotus . Hogan et al. (1997) , Walker et al. (2006) , and Greenbaum et al. (2017) reported low levels of mtDNA divergence between P. sejugis and P. maniculatus from Baja California but argued for retaining P . sejugis as a species based on unique morphometric and genetic characters (see Remarks below). Cyt b sequences (this study) indicated that P. sejugis differs from P. gambelii , P. keeni , P. labecula , and P. sonoriensis by 2.05%, 3.97%, 4.42%, and 4.42%, respectively. Given the sample of one individual, within species genetic variation could not be determined. Remarks.— A single sample was examined in this study that is assignable to P . sejugis . The specimen included herein was obtained from Mexico: Baja California Sur; Santa Cruz Island which is the type locality for P . sejugis . Based on our examination of only a single individual, and the unclear phylogenetic results obtained herein due to the fact that our sample of P . sejugis was paraphyletic with samples representing P . gambelii , we defer to the findings and synopses offered in Walker et al. (2006) and Greenbaum et al. (2017) who opined that based on the available data, it was best to retain P . sejugis as a species. Specifically, they presented six reasons for continuing to recognize P . sejugis as a species separate from mainland forms of P . maniculatus (referred to P . gambelii by Greenbaum et al. 2017 ). First, morphological evidence presented by Burt (1932) and Álvarez-Castañeda (2001) depicted external and cranial differences between samples of P . sejugis and mainland forms. Second, Avise et al. (1974) reported allozymic differentiation between P . sejugis and mainland populations. Third, Smith et al. (2000) , documented the appearance of a unique chromosomal inversion in P . sejugis . Fourth, Chirhart et al. (2005) reported a unique microsatellite allele in P . sejugis . Fifth, studies of mitochondrial DNA sequences ( Hogan et al. 1997 ; Walker et al. 2006 ; Cornejo-Latorre et al. 2017 ; Greenbaum et al. 2017 ) depicted samples of P . sejugis and P . maniculatus to form monophyletic clades, respectively. Sixth, given previous lines of evidence and based upon the insular and restricted distribution of P . sejugis ; as well as the surrounding conservation implications, demands careful treatment. Our data indicate that P. sejugis is allied closely with P. gambelii , similar to results generated in Greenbaum et al. (2017) . Genetic distance data generated herein suggest these populations diverged from P. gambelii found on Baja California Sur approximately between 0.44 and 0.67 mya (see Fig. 3 ).