The sponge Dosilia brouni (Spongillidae) in Lake Baringo, Gregory Rift, Kenya

Abstract

Living specimens of the sponge Dosilia brouni (Kirkpatrick, 1906), which had previously been found only in its type locality on the White Nile, have been discovered in Lake Baringo (Kenya). The sponge also occurs as subfossil gemmules embedded in the sediment. Its description is completed using light and scanning electron microscopy and physicochemical data on the habitat are given. The paleogeographical significance of this observation is discussed.

Dosilia (Porifera, Demospongiae) redefined

“…The sponges encrust the seasonally flooded marginal vegetation (KIRKPATRICK, 1906). Similar habitat conditions are described for the specimens at Lake Baringo (WORTHINGTON & RICARDO, 1936;VACELET et al, 1991). A probable dispersion of the species from the White Nile to Lake Baringo along early and middle Holocene is suggested by VACELET et al (1991).…”

“…Similar habitat conditions are described for the specimens at Lake Baringo (WORTHINGTON & RICARDO, 1936;VACELET et al, 1991). A probable dispersion of the species from the White Nile to Lake Baringo along early and middle Holocene is suggested by VACELET et al (1991). These authors report oligohaline waters of the Na-bicarbonate type for this shallow lake with short alternations between wet and dry periods and so dry and death periods for the vegetation and allied fauna at its marginal areas.…”

“…So the slides of Gee were from this sample, presently designated holotype by monotypy. VACELET et al (1991) describes the microscleres as acanthomicroxeas that may assume the aster aspect according to the length of the perpendicular rays present in the central region of the spicule. This way the just refered authors passed over with no discussion the original definition proposed by GRAY (1867) for the genus.…”

“…VACELET et al (1991) extended the range of Dosilia brouni from Sudan to Kenya in the Ethiopian Region and enlarged the species description offering SEM images of gemmules and gemmoscleres, besides offering precise data on the species habitat and a review of the bibliography considering its dispersion routes and present distribution in eastern Africa.…”

Cyanobacterial toxins in Lake Baringo, Kenya

“…GREGORY (BEADLE 1932). Since then several studies on the physico-chemistry, phytoplankton, primary production, flora and fauna have been carried out (JENKIN 1929;BEADLE 1932;VACELET et al 1991;PATTERSON ~:;WILSON 1995;ODOUR 2000).…”