Prorivulus auriferus, Costa, Lima, Suzart in Costa, 2004

History

Prorivulus auriferus is monotypic. Till now only one species belongs to the genus which was erected the same time with this species.

The name auriferus refers to the display of golden spots at the lower lateral sides of the body. auri (Aurum= gold) and ferus (Fero = bearing).

The species was first discovered by A.O. LIma and Rogrio R. Suzart, 28 June 2003.

Holotype is a male (30.3 mm standard lenght) from Valenca in the state Bahia, Northern Brasil.

Abstract

Prorivulus auriferus, new genus and species, from the coastal plains of northeastern Brazil, is described. It is a member of a monophyletic unit, including Rivulus and the clade comprising all annual fish rivulid genera, diagnosed by two unambiguous synapomorphies: unossified interhyal and distal process of the second epibranchial absent. Prorivulus is hypothesized to be the sister group of the monophyletic assemblage including Rivulus and the clade comprising all annual fish rivulid genera, which is defined by four unambiguous synapomorphies: shortened uncinate process of the third epibranchial, articular face of the distal edge of first hypobranchial anteriorly expanded, ventral process of angulo-articular narrowed, and posterior flange of cleithrum absent. Prorivulus is distinguished from other basal rivulid taxa by having five branchiostegal rays. (i.e., bony rays supporting the gill membranes behind the lower jaw).

The presence of five branchiostegal rays in Prorivulus is interpreted as autapomorphic. Other aplocheiloids have six branchiostegal rays, except the cynolebiatine Megalebias wolterstorffi (Ahl) with eight rays, the Plesiolebiatini genus Stenolebias and Rivulus romeri also with five rays (Costa, 1998, 2003b). Stenolebias is an annual fish genus, member of the Plesiolebiatini clade, which

 
Prorivulus auriferus - male. Image by Lee van Hyfte, USA.
 

includes other genera with six rays (Costa, 1998), and R. romeri is a member of the Rivulus atratus species group, which also includes several species with 6 rays (Costa, 2004b). Therefore, reduction to five branchiostegal rays is considered a homoplastic condition, occurring in three distinct rivulid lineages.

Diagnosis:

A non-annual fish genus, similar to Rivulus and Kryptolebias, and distinguished from the remaining rivulid genera by having anal-fin rays soft in both sexes (vs. hardened in females), urogenital papilla minute in males (vs. prominent and tubular), and absence of a dark bar on iris (vs. presence). Similar to Kryptolebias and distinguished from Rivulus by possessing frontal E-scales overlapped (vs. not overlapped), third epibranchial with distinct uncinate process (vs. short indistinct process), distal cartilage of the first hypobranchial restricted to articulation with first ceratobranchial (vs. cartilage expanded anteriorly), ventral process of angulo-articular broad (vs. narrow), and posterior flange of cleithrum absent (vs. present). Similar to Rivulus and distinguished from Kryptolebias by having unossified interhyal (vs. ossified) and by the absence of the distal process of second epibranchial (vs. presence). Differs from other rivulids, except the two species of Stenolebias and Rivulus romeri Costa, by having five branchiostegal rays (vs. six).


Reproduction

Keeping and breeding will be as easy as most Rivulus but a good cover of the aquarium is necessary because there ability to jump, even true the smallest opening, is unbelievable.

This species can, if there is enough space for them, housed in a tank with more males than one only and several females. If separated before and brought together again however, they can be very agressive to each other and fight to become dominant to others. The best way to have much offspring is to put a pair or an trio in a small tank from 10 liters with a small filter in it or with some airation. On the bottom some peat moss or dark gravel and a floating "mop" to give space for laying there eggs. The fish will, if they become a rich varity of life food, spawn during there whole adult life and produce daily between 5 to 15 eggs.

The eggs should be collected by hand and stored for about 14 days in a small container. Eggs are 1.6 mm and amber colored. It is wise, to add to the water you store the eggs in, some acryflavine to provent fungus coming up.

 

After hatching the young fry can eat fresh artemia nauplii without any problem. It takes 4 to 5 months to raise them to maturity.

There lifespan can be up to 3 years in captivity.

Remarks :

 


Variations
     

Map
     

Meristics

Max. size 4.0 cm.
Dorsal 9.5,
Anal 14.5,
D/A 8.5,
LL scale count (average) 32.5
Pre- dorsal length to % SL – 76.8 %
Depth to % SL – 20.0 %

   

Literature
Costa W.J.E.M 2004. A new Killifish Genus and Species from the coastal Plains of Northeastern Brsil (Teleostei: Cyprinodontiformes: Rivululidae). Zootaxa, 642: 3, fig 1-2. PDF