Revision of the Diploderma fasciatum (Mertens, 1926) Complex (Reptilia: Agamidae: Draconinae)
While taxonomic research of the genus Diploderma has made considerable progress in the past decade, far less attention was given to the arboreal species in the subtropical areas. Combining mitochondrial genetic and morphological data, we evaluated the current taxonomic hypotheses of one of the subtropical, arboreal species complexes, the D. fasciatum complex, based on examination of the type series and newly collected specimens. Mitochondrial genealogy shows that D. jinggangense, D. fasciatum, and D. szechwanense together form a monophyletic group, and D. jinggangense is paraphyletic to D. szechwanense. Although there are moderate genetic divergences among populations, such divergence differences are gradual geographically. Morphological comparisons of all commonly used diagnostic characters fail to differentiate the three species. In particular, the previously proposed diagnosis, the presence of transverse gular fold, is variable in this species complex. Our data support the previous taxonomic hypothesis that D. szechwanense and D. fasciatum are synonyms, and we also add D. jinggangense as another junior synonym of D. fasciatum. With newly available specimens, we revise the diagnostic characters of D. fasciatum, describe its coloration in life, and expand its distribution in southwestern and southern China. Our discovery of D. fasciatum in Guangdong Province represents a new provincial herpetofauna record. Finally, we highlight the taxonomic uncertainties on the species status of D. grahami with respect to D. fasciatum and discuss the issue on the recent unnecessary changes of the Chinese common names of the genus Diploderma, recommending maintaining stability of Chinese common names and continuous usage of “Long Xi” as the common name for Diploderma.
Distribution of the Diploderma fasciatum complex in China and Vietnam. Different colors code for different species, including D. grahami (orange) and D. fasciatum (blue). Stars and the shaded region indicate the type localities of recognized species, pentagons represents type localities of junior synonyms, and other shapes represent remaining sampling localities: circles indicate localities with both morphological and genetic data, rectangles indicate locality with only morphological or photographic evidence, and trapezoids indicate literature records. Specific localities include (1) Daweishan National Nature Reserve, Yunnan Province, China; (2) Lang Song, Vietnam (Nguyen et al., 2009); (3) Jinzhong Mountain, Baise City, Guangxi Zhuang Autonomous Region, China; (4) Cengwang Mountain, Guangxi Zhuang Autonomous Region, China; (5) Nanning, Guangxi Zhuang Autonomous Region, China; (6) Maoming City, Guangdong Province, China; (7) Nanling Nature Reserve, Guangdong Province, China; (8) Mangshan Nature Reserve, Hunan Province, China; (9) Fanjingshan, Guizhou Province, China (Zhang et al., 2011); (10) Chongqing Municipality, China; (11) Daguan County, Yunnan Province, China; (12) Tianquan County, Sichuan Province, China (E. Zhao, 2003); (13) Pengzhou (= Peng County), Sichuan Province, China (type locality of D. szechwanense); and (14) Jinggangshan, Jiangxi Province, China (type locality of D. jinggangense).
Mitochondrial genealogy of the genus Diploderma inferred from the 1032 bp coding region of the ND2 gene using both maximum likelihood (ML) and Bayesian (BI) analyses. ML bootstrap support values are mapped onto the BI topology. For each node, support values are given in the order of posterior probability/bootstrap value. “–” indicates inconsistent topology at the node in the ML analyses. All terminal nodes that unify recognized species are strongly supported (1.00/100), and hence the support values are omitted, except for those of the D. fasciatum complex. Enlarged inset shows details of the D. fasciatum complex, including population numbers of samples (which correspond to the ones in Fig. 1) and the status of the transverse gular fold of each individual specimen (A: absence; P: presence). Photo of live D. fasciatum is from Mangshan Nature Reserve in Hunan Province, photographed by Hang Zhou.
Comparisons of preserved specimens of the D. fasciatum complex, showing dorsal overview (1), ventral overview (2), lateral head (3), dorsal head (4), and ventral head view (5). (A) Holotype of D. fasciatum (SMF 9871); (B) specimen from the vicinity of the type locality of D. fasciatum from southeastern Yunnan, China (KIZ 040192); (C) holotype of D. szechwanense (CIB 2620); (D) holotype of D. jinggangense (SYS r00988); (E) male specimen from Guangdong, China (SYS r001441); (F) male specimen from northeast Yunnan, China (KIZ 044140); and (G) holotype of D. grahami (USNM 65500). Photos by Gunther Köhler, Shuo Qi, Kai Wang, and Chenqi Lu.
Comparisons of live coloration (1: dorsolateral; 2: lateral head and oral cavity/tongue; and 3: ventral head) among different populations of D. fasciatum in China. (A–E) Vouchered specimens, (F–H) non-vouchered individuals. (A) Topotypic D. fasciatum, young adult female, KIZ 040192 (population 1 in Fig. 1); (B) SYS r001583, adult male (population 6); (C) KIZ 037765, adult male (population 4); (D) KIZ 044140, adult male (population 11); (E) SYS r001847, adult male (population 13); (F) adult male (population 1); (G) adult female (population 6); and (H) adult female (population 10). Photos by Kai Wang, Jian Wang, Jianyue Qiu, Xinqiang Song, Yulong Li, and Chenqi Lu.
Contributor Notes
Associate Editor: B. L. Stuart.