TWO NEW RIVULUS SP-abstract

Abstract

ABSTRACT.
Following new collections in coastal and inland north-western Colombia, Rivulus pacificus Huber, 1992, is redescribed based on live nearby topotypes, then redefined in a restricted sense, and two new cryptic congeners, also from the Colombia lowlands, are described as Rivulus gomesi n. sp., and Rivulus paradiseus n. sp., both from the north-western lowlands, in the Atrato river system, near Chigorodó, Antioquia for the former and in the Acandí river basin, facing the Caribbean coast near Acandí, close to the Panama border, for the latter. The three species form a group of closely related species, not morphologically related and not pattern-wise related to the elegans species group, dominant in the Northern Colombian Andes and inter-Andean valleys and vicariant. Instead, they are morphologically more related to the micropus species group with a huge distribution in northern and north-eastern South America. The three species are not separable by morpho-meristics but are diagnosed by a combination of pattern characters in male and female. R. gomesi is mainly separated from the similarly-morphed pacificus by the presence of a supracaudal ocellus in females and by body pattern (red lines faint and irregular vs. fully lineated in pacificus males) ; R. paradiseus mainly differs from R. gomesi, also with a supracaudal ocellus in female (unlike pacificus, missing one), by body pattern (5 to 6 evenly interrupted red lines vs. irregularly scattered red lines and by posterior Anal fin and basal Caudal fin with reticulated inner (green spots, not red) pattern vs. few red dots. R. gomesi and R. paradiseus do fit well into the micropus group according to latest evidence. On the contrary, the elegans species group differs in Colombia from all members of the micropus group by having a more forward set Dorsal fin relative to the Anal fin; truncated Caudal fin vs. rounded; a larger maximum size (up to 90 mm TL vs. 63 mm TL on average. The 3 species of the R. pacificus group are separated notably from vicariant R. elegans and its 3 allied (chucunaque, sucubti, that taxon being formally proposed as a junior synonym of chucunaque, and leucurus) by live pattern and morphology. Hypotheses to explain the present distribution are forwarded.

Key words: killifish, redescription, Rivulus pacificus group, misidentification, Cyprinodontiformes, coastal Colombia.

Full text

TWO NEW RIVULUS SP. FROM NORTH-
WESTERN COLOMBIA, AFTER A
REDESCRIPTION OF RIV. PACIFICUS
(CYPRINODONTIFORMES, RIVULIDAE).
Two new Rivulus sp. from north-western Colombia, after a redescription of
Riv. pacificus (Cyprinodontiformes, Rivulidae).
Jean H. Huber ¹, D.A. Mejía-Vargas ² & F.B.M. Vermeulen 3
1 Ichtyologie, Museum national d’Histoire naturelle, 43 rue Cuvier, 75231 Paris
Cedex 05, France | Private address for correspondence : 7 Boulevard Flandrin,
75116 Paris, France (corresponding author, mail through www.killi-data.org).
2 San Antonio del Tequendama, Cundinamarca, Colombia. E-Mail:
pyrrhura@gmail.com
3 Tanki Leendert 194 c, Aruba. E-Mail: vermeulen@setarnet.aw
ABSTRACT.
Following new collections in coastal and inland north-western Colombia, Rivulus
pacificus Huber, 1992, is redescribed based on live nearby topotypes, then
redefined in a restricted sense, and two new cryptic congeners, also from the
Colombia lowlands, are described as Rivulus gomesi n. sp., and Rivulus
paradiseus n. sp., both from the north-western lowlands, in the Atrato river
system, near Chigorodó, Antioquia for the former and in the Acandí river basin,
facing the Caribbean coast near Acandí, close to the Panama border, for the
latter. The three species form a group of closely related species, not
morphologically related and not pattern-wise related to the elegans species group,
dominant in the Northern Colombian Andes and inter-Andean valleys and
vicariant. Instead, they are morphologically more related to the micropus species
group with a huge distribution in northern and north-eastern South America. The
three species are not separable by morpho-meristics but are diagnosed by a
combination of pattern characters in male and female. R. gomesi is mainly
separated from the similarly-morphed pacificus by the presence of a supracaudal
ocellus in females and by body pattern (red lines faint and irregular vs. fully
lineated in pacificus males) ; R. paradiseus mainly differs from R. gomesi, also
with a supracaudal ocellus in female (unlike pacificus, missing one), by body
pattern (5 to 6 evenly interrupted red lines vs. irregularly scattered red lines and
by posterior Anal fin and basal Caudal fin with reticulated inner (green spots, not
red) pattern vs. few red dots. R. gomesi and R. paradiseus do fit well into the
micropus group according to latest evidence. On the contrary, the elegans
species group differs in Colombia from all members of the micropus group by
having a more forward set Dorsal fin relative to the Anal fin; truncated Caudal fin
vs. rounded; a larger maximum size (up to 90 mm TL vs. 63 mm TL on average.
The 3 species of the R. pacificus group are separated notably from vicariant R.
elegans and its 3 allied (chucunaque, sucubti, that taxon being formally proposed
as a junior synonym of chucunaque, and leucurus) by live pattern and
morphology. Hypotheses to explain the present distribution are forwarded.
Key words: killifish, redescription, Rivulus pacificus group,
misidentification, Cyprinodontiformes, coastal Colombia.
Zoobank.org:pub: AD44E336-EF70-442B-AC70-63A128F39E1