Most of the species within
the Gobiosoma are found in the Caribbean region, an area with
a complex geologic history. If the ancestors of Gobiosoma came
from the eastern Atlantic and Mediterranean regions, they would
most likely have traveled with the North and South American
plates when the Atlantic Ocean was forming. This assumes that
the ancestors were basically benthic species with short larval
stages which would have restricted their dispersal across the
Atlantic to their present locations. Past studies by Birdsong
et al. (1988), along with findings by Van Tassell 1998 support
a Mediterranean and eastern Atlantic origin for the group.
Their past evolutionary history
in the Americas would have been influenced by a number of vicariant
events such as 1) the movement of the Caribbean plate eastward
into the Atlantic; 2) the formation of the Caribbean island
systems and; 3) the biolide impact near the present Yucatan
peninsula 65 million years ago (Hedged, 1996). The separation
of the Pacific and Atlantic Oceans with the formation of Central
America, the resultant changes in oceanic circulation patterns,
and the formation of coral reefs in the Caribbean further divided
the species and provided additional niches for rapid evolution
of species. Rapid evolution of species within the group is particularly
evident among the species in the Elacatinus complex. The 13
species within this genus (as define by Van Tassell 1998) all
exhibit very similar color patterns and many readily hybridize
in the aquarium.
Additional readings:
Hedges, S.B. 1982. Caribbean biogeography: Implication of
recent plate tectonic studies. Syst. Zool. 31(4): 518-522.
Hedges, S.B., Hass, C.A. and L.R. Maxson. 1994. Reply: Towards
a biogeography of the Caribbean. Cladistics 10: 43-55.
Hedges, S.B. 1996. Historical biogeography of the West Indian
vertebrates. Ann. Rev. Ecol. Syst. 27: 163-196.
Page, R.D. and C. Lydeard. 1994. Towards a cladistic biogeography
of the Caribbean. Cladistics 10: 21-41.
