Millerichthys robustus, Miller & Hubbs, 1974

History

See for more detailed info the Millerichthys introduction page.

Gordon mentionned the species as Rivulus robustus but it became a nomum nudum. (name not in use)

The description follwed in 1974 by Miller & Hubbs was also Rivulus robustus till Costa erected a new genus for it based on major abnormalties in osteology and meristic issues compared to those in the genus Rivulus.

The scientist Dr. Jean Huber did offer a grant for young researchers to re-locate the species as it was not possible to find it since the first report and description. The species is re-discovered just a short while ago. (2013)

The cyprinodontiform family Rivulidae is a diversified group of killifishes, with currently more than 324 valid species occurring between southern Florida and northeastern Argentina (Costa, 2008). A part of the rivulid taxa, known as annual killifishes (Myers, 1942), are uniquely found in swamps and isolated pools that seasonally dry (Nico et al., 1987; Costa, 1995, 1998). The ability to survive in seasonal swamps and pools is due to the thickened chorion eggs, which make eggs resistant to water loss, and a complex embryonic development including diapause (Wourms, 1972a-c). Three rivulids species are reported in Mexico: Rivulus (Cynodonichthys) tenuis, Kryptolebias marmoratus, and Millerichthys robustus (Huber, 1992; Costa, 2008). Millerichthys robustus is known from the Papaloapan and Coatzacoalcos River drainages (Miller & Hubbs, 1974), and was included in the subfamily Rivulinae in Costa (1998, 2008) but not
in Costa (2011). To date, there is no data available about its lifestyle (Huber, 1992; Costa, 1995, 1998).
The primary purpose of the present study is to describe its annual nature.(O. D. Castanedo et al 2013).

 
Millerichthys robustus - preserved male . This image was taken with permission from the manuscript by Dominguez O.C., M.A.C., Mosqueda S. Valdesalici, 2013.
Millerichthys robustus - preserved female. This image was taken with permission from the manuscript by Dominguez O.C., M.A.C., Mosqueda S. Valdesalici, 2013.

 

Millerichthys robustus survives in ephemeral pond habitats from Papaloapan river basin in Mexico by producing drought-tolerant diapausing embryos. Four stages in fertilized embryos were observed: Dispersion/re-aggrega- tion, Diapause I, Diapause II, and Diapause III confirming its annualism. Eggs extracted from soil when the pool was completely dry were found in Diapause I. The chorion surface ornamentation is reported for this species for the first time.


Reproduction

No data yet.

 

 


Variations
© Drawing is made and donated by Ruud H. Wildekamp, The Netherlands from his AKA publication "A World of Killies, Vol. 2." The material is being reprinted with permission of both, Ruud Wildekamp and the American Killifish Association. This diagram may not be copied or used on any other web site.

Map

   

Meristics

Max. size SL 4.0 cm.
Dorsal 12.0,
Anal 15.0,
D/A 6.0,
LL scale count (average) 32.0
Pre- dorsal length to % SL – 69.0 %
Depth to % SL – 24.0 %

   

Literature

Miller, R.R. & C.L. Hubbs. 1974. Rivulus robustus, a new Cyprinodontid Fish from Southeastern Mexico. Copeia: 865, figs. 1-3.

Dominguez O.C., M.A.C., Mosqueda S. Valdesalici, 2013. First Observations of Annualism in Millerichthys robustus (Cyprinodontiformes: Rivulidae).
Ichthyol. Explor. Freshwaters, 24 (1) (July): 15 - 20, 3 figs., 1 tab.(PDF) right click to open in new window

Dominguez, O.C. & M.C. Uribe. 2019. Ovarian Structure, Folliculogenesis and Oogenesis of the annual killifish Millerichthys robustus (Cyprinodontiformes: Cynolebiidae). * Journal of Morphology (J. Morphol.), 13 pp.,