Amphilophus globosus

The most recent discovery from Lake Apoyo is Amphilophus globosus. Amphilophus globosus stands out from other Midases by its characteristic shape, his bright yellow-green colour and the absence of the cross bands outside of the mating season.

Description

Etymology

Globosus is Latin for round or spherical, referring to the crest shaped build of this species.

Description

The most recent discovery in Lake Apoyo is Amphilophus globosus. Its discovery is the sixth and therefore currently last described Midas cichlid from this caldera lake. Amphilophus globosus can be easily separated from other Midases by his characteristic shape, the bright yellow-green colouring and the lack of cross band markings outside of the breeding season. The only items remaining from the seven cross bands are the two very remarkable spots. One of these is mid-lateral, on the third band and a smaller spot on the caudal peduncle toward the root of caudal fin. Both male and female are equal in colouring and marking. The pelvic fin is transparent yellow and the anal fin is light coloured. One of the few existing photo’s (which we can’t disclose with you) shows a specimen pictured of which the bottom section of the caudal fin has vague reddish colouring.

Because the species discovered in Lake Apoyo are still recent and not well defined, regularly hybrids are formed. Scientists find evidence of this often in the genes of the fish. Of all Midases in Lake Apoyo, it seems that Amphilophus astorquii is often the dominant species (by preference with Amphilophus flaveolus). Amphilophus astorquii is however the most spread species of the pack so this explains the dominance in the hybridisation. On the other side of the spectrum we can find Amphilophus globosus. Of all species in Lake Apoyo, Amphilophus globosus is the most faithful to its own phenotype. This is the reason why genetically this Midas is one of the most isolated and best-defined species in Lake Apoyo besides the Amphilophus zaliosus.

As this is a recent discovery (2010) there is not much known in regards to this species. We will keep ourselves to providing the necessary and general information regarding these fish.

Habitat

This fish is endemic to the Laguna de Apoyo in Nicaragua. This caldera lake is situated in a near round shaped volcanic caldera, roughly 4 kilometres west of Lake Nicaragua. The surface is 5 kilometres across in length, is 21 km2 and its 178 metres in depth. The caldera has formed after a series of volcanic eruptions of which the last occurred 23.000 years ago. The lake is situated 70 metres above sea level, has no other links with other bodies of water and the level has dropped with 15 metres since the 1950’s. The water is poor in nutrients, warm (27 – 29,5°), alkaline (pH = 8.1) and brackish (Na +640mg/l).

Biodiversity in the lake is low. It contains he Midas-cichlids; Amphilophus zaliosus, Amphilophus astorquii, Amphilophus chancho, Amphilophus flaveolens, Amphilophus supercilius and Amphilophus globosus. Parachromis managuensis, also a cichlid, the salmon Atherinella sardina, the livebearer Poecilia sphenops and non-indigenous species Oreochromis niloticus and Gobiomorus dormitor. The lake itself has hardly any vegetation besides a few grass like species (Typha and Scirpus) and starting at a depth of 3 metres Chara sp. (musk grasses).

Behaviour

As this species is new, there is no information regarding its behaviour when drafting this article.

Diet

This species surprisingly does not eat snails. Pyrgophorus coronatus is a widely spread, little snail of Lake Apoyo. It’s so numerous that the beaches of the lake mostly are formed from fragments of this snail. As this prey animal is so easily available, it’s common for most Midases to have it as their main food source. Amphilophus globosus however is the exception. No snail remains have been found in their stomachs.

Breeding

It’s observed that Amphilophus globosus prefers to breed between the musk grasses at a depth of 4 to 8 metres. The couples show more of their cross band patterns during the mating season. This however consists of some more nuances in the mid lateral colouring. Seven spots on a row with the caudal spot form this irregular cross band marking.

The tank

As there a no fish kept in captivity there is currently no information available.

References

Geiger M. et al. 2010. Description of two new species of the Midas cichlid complex from Lake Apoyo, Nicaragua.

Holotype ZSM 38822: volwassen man van 16 cm, gevangen aan de Noord-Westkust op 17-04-2009.

Literature

– Estation Biologica 2011. http://lagunadeapoyo.blogspot.nl/2011/04/nesting-amphilophus-globosus.html

– Geiger M. et al. 2010. Description of two new species of the Midas cichlid complex from Lake Apoyo, Nicaragua.

– Geiger M. et al. 2013. Crater Lake Apoyo Revisited – Population Genetics of an Emerging Species Flock.

 

Author

Rene Beerlink

Copyright sketch

Rene Beerlink

Additional information

Family

Genus

Species

Breeding behaviour

Origin

Ecosystem

Temperature minimum

Temperature maximum

pH minimum

pH maximum

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