DesDescriptioncription
Redescription of the seasonal killifish species Nothobranchius
ocellatus and description of a related new species Nothobranchius
matanduensis, from eastern Tanzania (Teleostei:
Nothobranchiidae) Ichthyological Exploration of Freshwaters: IEF-
1149: 28 pp
Abstract:
The description of Nothobranchius ocellatus was based on a
unique holotype, comprising an immature male, and a photograph
of a female. The holotype is apparently lost. The species is here
redescribed in detail, and a neotype designated from a site near
the original type locality. The range of distribution of the species is
within the lower Rufiji and lower Ruvu river systems, contained
within intersecting, tectonically-controlled and
hydrologicallylinked graben structures, the Rufiji Depression and
Ruvu Valley Trough, and at relatively low elevations. Disjunct
populations in the Matandu River drainage, previously regarded as
the same species, are described as Nothobranchius matanduensis
Watters, Nagy & Bellstedt, new species. The latter species occurs at
significantly higher elevations than those of N. ocellatus and
appears confined to a part of coastal Tanzania that has been
tectonically relatively stable. The two species comprise the
‘Nothobranchius ocellatus species group’. Differences in diagnostic
characters between N. matanduensis and N. ocellatus are
presented, the most obvious of which are grey scale margins and
black spots on the head of males of the former (vs. red-brown scale
margins and red-brown spots on the head of the latter). Further
differences in colour pattern and morphology of both males and
females of the two species are described in detail, and differences
in cephalic sensory systems are also noted. Genetic divergence in
partial sequences of the mitochondrial genes, ND2 and COI, and
three nuclear genes, Glyt, MyH6 and SNX33, supports the genetic
distinction of the two species within a well-defined N. ocellatus
Clade, which is deeply rooted in Nothobranchius, thereby also
confirming the subgenus status of Paranothobranchius. The
ecology and biology of the species group is reviewed; both species
are relatively large and piscivorous in nature, occupy seasonal
habitats, and always occur syntopically with various other,
smaller, Nothobranchius species.
Clasification
Genus: Nothobranchius
Subgenus: Paranothobranchius
Group:
Geographical Distribution
Maps
Tanzania
Type locality:TMatandu drainage: floodplain between Liwale and
Makubwa tributary systems: small pool on the north side of the road at a
culvert, 45 km northeast of Liwale in the direction of Kilwa, 09°32.7' S,
38°10.4' E.
Locations/codes
PK 45 Liwale
TAN 97-29,
Notes
Status specie: Not unanimously confirmed
Bibliography
Related: