CYPRINODONTIFORMES

Phillip, Dawn A. T., Taphorn, Donald C., Holm, Erling, Gilliam, James F., Lamphere, Bradley A. & López-Fernández, Hernán, 2013, Annotated list and key to the stream fishes of Trinidad & Tobago, Zootaxa 3711 (1), pp. 1-64 : 20-21

ORDER CYPRINODONTIFORMES

FAMILY POECILIIDAE

Poecilia boesemani Poeser 2003 [liberty Molly (in Trinidad)]

Brackish and fresh water (Kenny 1995). Endemic to Trinidad, but possibly also present on adjacent mainland Venezuela; described from the Maraval River, Trinidad (Poeser 2003). Internal fertilisation; livebearer; capable of breeding in oceanic water (Kristensen 1970). Omnivore. 40 mm.

Recent work by Poeser (2003) has resulted in the division of previous, supposedly widespread, Poecilia “species" into several more locally distributed species, among them P. boesemani from Trinidad. Before this, P. boesemani in Trinidad was identified as P. sphenops , with populations in Diego Martin (immediately west of Maraval) and St. Augustine, but Poeser did not include samples from these other populations. It is believed that P. sphenops may have been introduced (Kenny 1995).

Poecilia picta Regan 1913 [millions, swamp guppies]

Lowland, fresh, and brackish (Reznick et al. 1992; Kenny 1995), stagnant and flowing, clear and turbid water (Kenny 1995), in habitats including stream mouths, lagoons and sluggish-flowing water (Reznick et al. 1992), penetrating far inland in low-elevation streams in Trinidad and Tobago (Kenny 1995). Native. Internal fertilisation; livebearer (Reznick et al. 1992). Omnivore. 50 mm.

Poecilia reticulata Peters 1859 [millions, rainbow fish, seven colours, guppy, mosquitofish, big belly fish]

Various habitats, from clear headwaters to turbid lowland streams, standing waters and drainage ditches, throughout Trinidad (Kenny 1995); also some streams in southwest Tobago (Phillip 1998). Native. Viviparous with continuous, year-long reproduction (Alkins-Koo 2000). Omnivore, feeding on algae and insects (Dussault & Kramer 1981). 65 mm.

Schories et al. (2009), based a molecular phylogenetic analysis using mitochondrial DNA, split P. reticulata , describing a new, cryptic species, Poecilia (Acanthophacelus) obscura , from part of the North Oropuche drainage in east Trinidad. Baillie (2012) rejects this position based on an analysis of genetic differentiation of P. reticulata throughout T&T, citing insufficient genetic separation between the Oropuche and other guppies; there is evidence of gene flow and introgression between the Oropuche guppies and those from other parts of the island. We follow Baillie (2012) in not recognising P. obscura as a valid species.

Poecilia vivipara Bloch & Schneider 1801 [swamp guppy, swamp millions]

Rarely in fresh water, preferring brackish water (Kenny 1995); canals and ditches near swamps (Kenny 1995), in upper, middle, and lower reaches of stream catchments (Figueiredo Medeiros et al. 2006). In Trinidad, it is found in brackish reaches of streams on all but the north coast (Kenny 1995). Native. Internal fertilisation; livebearer. Omnivore. 50 mm.

FAMILY RIVULIDAE

Anablepsoides hartii (Boulenger 1890) [jumping guabine, jump and bend, madfish, small guabine] Widely distributed in streams throughout Trinidad (Kenny 1995, Phillip 1998), from headwater streams to drainage ditches and swamps, and from fresh to weakly brackish water; also in some streams accross Tobago (Kenny 1995, Phillip 1998). Tolerant of low dissolved oxygen conditions; can tolerate exposure to moist air, and move short distances over land. Native. Sticky eggs deposited on various substrates including living or dead vegetation and gravel. Carnivore. 110 mm.

Removed from the genus Rivulus to Anablepsoides by Costa (2011). Although we here refer to all Rivulus (= Anablepsoides ) from Trinidad as A. hartii , recent genetic work (Walter et al. 2011) indicates that differentiation has occurred, some of which warrants taxonomic recognition.

Kryptolebias marmoratus (Poey 1880) [mangrove rivulus ]

Salt marshes, estuaries, ditches, and puddles with salt to fresh water; tolerant of habitats with low dissolved oxygen; can tolerate long exposure to air (Abel et al. 1987, Sayer 2005). Southwestern peninsula, Trinidad. Native. Simultaneous, self-fertilising hermaphrodite (Harrington 1961), though there are true males and sexual reproduction in some populations (Mackiewicz et al. 2006); eggs attached to various surfaces. Carnivore/ omnivore. 80 mm.