Mitogenomic phylogenetics of the wild silkmoth genus Samia Hübner, 1819
The wild silkmoth genus Samia Hübner, 1819 (Saturniidae) contains a
number of economically important species in industrial silk production.
However, the interspecific relationships within the genus remain
unclear. We sequence the mitogenomes of Samia watsoni Oberthür, 1914 and
Samia wangi Naumann & Peigler, 2001. Both mitogenomes are annotated and
found to be cyclized, with 37 genes (13 PCGs, 2 rRNA genes and 22 tRNA
genes). Using maximum likelihood and Bayesian inference methods, we
analyze these mitogenomes together with a further 68 downloaded from
GenBank (65 Bombycoidea and 5 Lasiocampidae as the outgroup) to
investigate both the phylogenetic relationships both within the genus
and those among the three families of the ‘SBS’ group: Bombycidae,
Saturniidae and Sphingidae. The results show that within Samia, S.
ricini is closely related to S. canningi, and not S. cynthia of which it
has been considered a subspecies. Although arguments have been proposed
to treat S. ricini and S. canningi as conspecific, we choose to accept
the morphological arguments and continue to treat them as two separate
species. Samia watsoni is corroborated as the sister group of all other
Samia species, but nevertheless should be included within Samia rather
than being placed in its own monobasic genus. Our analysis recovers the
following relationship among the three families of the ‘SBS’ group:
(Saturniidae + (Bombycidae + Sphingidae)). This agrees with previous
studies based on analysis of mitogenomes but continues to contradict the
results derived from phylogenomic analysis of nuclear genomes.