Gazella arabica - lost and found?Abstract:
With this study we’ve set out to chase a mystery: Gazella arabica Lichtenstein,
1827. Based on only two specimens in the Museum für Naturkunde Berlin,
this taxon has puzzled researchers for more than a century. Its former
distribution, phylogenetic position and species status are unclear. The
taxon is now considered extinct, status “data deficient” (IUCN/SSC Antelope
Specialist Group 1996). We provide a first molecular characterization of the
type material, using sections of the mitochondrial cytochrome b gene and
the mitochondrial control region. Additional sequences, from other museum
specimens assigned to G. arabica, as well as living gazelles and previously
published sequences available on GenBank complement the data set. We
further sequenced parts of the mitochondrial 12S gene for several living
gazelle species in order to increase the overall amount of sequence data
available for investigating gazelle phylogeny.
Introduction:
Throughout the 19th century, G. arabica was used as the species name
for all gazelles living in Arabia (Groves 1983), until the presence of
several distinct species was acknowledged. Along with the other Arabian
gazelles, the status of G. arabica has repeatedly been changed from
a species to a subspecies of G. gazella, to a subspecies of G. dorcas
and back to a distinct species. Furthermore, the original type material
was later considered to consist of two distinct taxa: Neumann (1906)
designated the male specimen (Fig. 1) from the Farasan archipelago the
lectotype of G. arabica and erected a subspecies, G. arabica rueppelli,
for the female (Fig. 2) from Sinai, based on differences in coloration.
Here we test, using molecular phylogenetics, whether G. arabica is a
distinct species separate from all other gazelle species, or a synonym
of G. dorcas or G. gazella.
Conclusions:
With the newly sequenced molecular data we are able to re-evaluate the
systematic and taxonomic status of G. arabica: both type specimens do not
form a separate clade and the name is synonymous with G. dorcas. However,
as the name G. arabica was commonly used for the gazelles in Arabia, not all
specimens labeled “G. arabica” necessarily belong to G. dorcas, but could be
members of G. gazella, as previous authors have hypothesized (e.g., Rostron
1972; Wronski et al. 2010), and as ZMB 66104 and ZSM AM/1063 demonstrate.
The increased amount of sequence data clearly indicates four clades among
gazelles, but needs further investigations to resolve their interrelationships.
Results and Discussion:
Both type specimens, ZMB 2115 and ZMB 2108, are nested within a monophyletic
G. dorcas clade. This placement of ZMB 2108 supports Groves (1983) who concluded
that G. a. rueppelli is a junior synonym of G. dorcas isabella based on skull dimensions.
It is however surprising for ZMB 2115 which is morphologically more similar to
G. gazella (Baermann et al. in prep.) and remains to be verified.
The skin ZMB 66104 as well as the specimen labeled ZSM AM/1063 both belong to
G. gazella; the numberless skin (ZMB, a zoo specimen from 1965) seems to be a
misidentified G. subgutturosa.
G. bilkis Groves and Lay, 1985 which is sometimes considered a subspecies of
G. arabica (Groves 1996), is a synonym of G. gazella.
There are four monophyletic groups in Gazella (numbered clade 1-4 in Fig. 3) which
form the same unrooted tree (1,2,(3,4)) in all three separate analyses (data not
shown). However, this tree is rooted at different branches when outgroup species are
included. Using cytb, the outgroup (represented by the genera Nanger, Eudorcas, and
Antilope) roots the Gazella ingroup between clade 1 (G. dorcas + G. saudiya) and the
remaining species; in the separate 12S analysis, the outgroup roots the tree between
clade 3 (G. subgutturosa + G. bennetti) and the remaining species. In the combined
analysis (Fig. 3) the tree is rooted again between clade1 and the remaining species,
but the branch support from posterior probabilities is very low. Longer sequences and
additional markers as well as extended taxon sampling will be necessary to settle these
contradictory results.
Source:
people.pwf.cam.ac.uk/evb24/Baermann_et_al_DGS_Poster_Gazella_arabica.pdf 
;D
;D
