Cyprinodon desquamator MARTIN & WAINWRIGHT, 2013

Scale-eating pupfish

Etymology

Cyprinodon: from the Ancient Greek κυπρῖνος (kuprinos), meaning ‘carp’, and ὀδούς (odous), meaning ‘tooth’.

desquamator: from the Latin squamare, meaning ‘one who removes scales from fishes’.

Classification

Order: Cyprinodontiformes Family: Cyprinodontidae

Distribution

Endemic to San Salvador Island in the Bahamas where it’s known from six hypersaline lakes; Crescent Pond, Osprey Lake, Oyster Lake, Little Lake, Mermaid Pond and Great Lake.

Type locality is ‘San Salvador Island, Bahamas: Crescent Pond, 1 km SE of the Gerace Research Centre, lat 24°06’45″N, long 74°27’28″W’.

Habitat

The lakes inhabited by this species are shallow and rarely exceed 3 metres in depth, with the fish most abundant in mats of macroalgae (Batophora, Acetabularia and Cladophora) and wigeongrass (Ruppia maritima) in the littoral zones.

C. desquamator occurs sympatrically alongside the congener C. variegatus in all of them, and with C. brontotheroides in four of the six.

Although Cyprinodon spp. inhabit a diverse range of environments, from freshwater rivers and lakes to brackish estuarine waters, isolated springs and hypersaline lagoons, almost all of them have a diet composed of algae and organic detritus and present allopatric patterns of distribution.

However, those inhabiting San Salvador and Lake Chichancanab in Quintana Roo state, Mexico have evolved into groups of species occurring in sympatry and exploiting diverse but specific resources with some spectacular morphological adaptations (see ‘Notes’).

Unfortunately several of the Chichancanab species are now extinct in the wild due to introduction of Oreochromis spp. (tilapia) and Astyanax affinis during the 1990s, and Martin and Wainwright (2013b) warn of a similar situation on San Salvador since Oreochromis is already present in at least two water bodies.

Maximum Standard Length

The largest individual known to date measured 30.7 mm.

Diet

This species is a specialised lepidophage with approximately 50 % of the diet comprising the scales of other fishes.

Physical adaptations to this behaviour include its elongate body and jaw mechanism permitting a fast biting action.

Sexual Dimorphism

Mature males possess a metallic blue anterodorsal region but lack the typical black margin on the caudal-fin, this being replaced by black pigmentation on the
median fins.

Nuptial males display grey or black ventral colouration, versus orange in the majority of congeners.

Females and juveniles have a black and white ocellus on the dorsal-fin.

Reproduction

Males have been observed guarding breeding in water of 0.05 to 1 m depth, and although breeding has been observed year-round it seems to be most common in summer.

NotesTop ↑

This species was referred to as C. sp. ‘lepidophage’ or C. sp. ‘scale-eater’ prior to description.

It differs from congeners by possession of large supra-terminal jaws and an elongated body shape, plus the colour pattern in adult males which consists of solid black pigmentation throughout the entire body and median fins.

No other Cyprinodon species are adapted to feeding on fish scales so research has been conducted to establish whether unique mechanisms have driven the evolution of such ecological novelty. Click here for further information.

References

1. Martin, C. H. and P. C. Wainwright, 2013b - Bulletin of the Peabody Museum of Natural History 54(2): 231-240
   Remarkable Species Flock of Cyprinodon Pupfishes Endemic to San Salvador Island, Bahamas.
2. Martin, C. H. and P. C. Wainwright, 2013a - Science 339(6116): 208-211
   Multiple Fitness Peaks on the Adaptive Landscape Drive Adaptive Radiation in the Wild.
3. Martin, C. H. and P. C. Wainwright, 2011 - Evolution 65(8): 2197-2212
   Trophic novelty is linked to extremes rates of morphological diversification in two adaptive radiations of Cyprinodon pupfishes.