Micromoema xiphophora, Thomerson & Taphorn, 1992

History

In 1992 the authors of the descriptin of Pterolebias xiphophorus named this species referring to the sword- like caudal fin. ( xiphophorus = bearing a sword)

Costa placed the species in the special for this fish erected new genus named Micromoema and by that it became Micromoema xiphophorus.

Seegers (2000) renamed it in Micromoema xiphophora.

The original terra typica was situated alon the right bank of the Ventuari river, about 5,5 km upstream from the spot where the Rio Yureba comes into the Ventuari. Other habitats are found in the upper Orinoco region along the border of Venezuela and Colombia near Porto Ayacucho and near the remote village San Juan de Manapiare.

I myself found the species in Januari 2009, together with my German friend Siegmund Sladkowski not far from Porto Paez together with Rachovia aff. maculipinnis in a pool covered by trees and with athick layer of grey clay.

At the upper right side you see a varity found at Isla Raton by Dr. Roger Brousseau. It differs from the original description by having a more dense pattern of spots and stripes that form lines. This is not seen at the original species which is shown beneath.

 
Micromoema xiphophora - male. Isla Raton. Image made by F.Vermeulen.
Micromoema xiphophora - female. Isla Raton. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - male. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - female. Image made by F.Vermeulen.

Reproduction

Micromoema spawns their eggs by diving in a layer of soft pH neutral clay in their natural habitat but also spawn at the surface of the bottom.

The strain from Isla Raton is not to difficult to breed as eggs stay in good condition for the 4-5 months they need to eye-up. It is wise to store them at high temperatures like 26-30 C. as they will need many months more if kept at lower temperatures. The new strain VSV 2009-04 from near Puerto Paez is problematic to breed. The eggs, all of them almost, get white within the first 10 days and die. I did try all kind of spawning media like cocopeat, peat, peat with clay, only clay, wet- or dry storage, hot or cool storage, all you can think of. Only a few eggs survived and of more than 1000 eggs I could get 3 juveniles. These became 2 males and one female that did produce eggs now that stay alive for 30 %. Let's see what this will bring.

 

Normally the eggs should be stored in damp medium for about 4 months. Check than for eyed up eggs. After the first watering the peat should be re-dried and stored for another period of 2 - 4 weeks to take advantage of the eggs that did not develop as quick as the other ones.

 


Variations
Micromoema xiphophora - male. Isla Raton. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - male. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - pair. Image made by F.Vermeulen.
Biotope of Rachovia maculipinnis VSV 2009-04 and Micromoema spec. SVS 2009-04 author collecting. Image made by Siegmund Sladkowski, Germany.
Micromoema xiphophora - adult male. Isla Raton. Image made by F.Vermeulen.
Micromoema xiphophora - juvenile male. Isla Raton. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - female. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - male. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - male. Image made by F.Vermeulen.
Micromoema spec. VSV 2009-04 - male. Image made by F.Vermeulen.

Map
   

Meristics

Max. size 6.0 cm.
Dorsal 8.9,
Anal 12,6
D/A 8,0
LL scale count (average)29.7
Pre- dorsal length to % SL – 72.5 %
Depth to % SL – 18.9 %

   

Literature
Thomerson, J.E. & D.C. Taphorn. 1992. Two new annual Killifishes from Amazonas Territory, Venezuela (Cyprinodontiformes: Rivulidae). Ichthyol. Explor. Freshwaters, 3 (4): 378, figs. 1-2. PDF (rightclick to open in new window)