ANL arnoulti NUC nuchimaculatus No photos exist. From Paul Loiselle's review of Pachypanchx: Guichenot (1866) described Poecilia nuchimaculata from a single specimen collected by J. P. Goudot, a French resident of Madagascar from 1835 until his death in the early 1860's. The specimen lacks precise locality data and as Goudot’s journals were lost when he disappeared while in the field (Dorr, 1997), subsequent efforts to determine its provenance have proved fruitless. Published data (Huber, 1998) indicate that with regard to both morphometric and meristic characters the type falls within the range that defines the Malagasy representatives of the genus Pachypanchax. He noted that the prefrontal scales of this specimen are smaller than those of other Pachypanchax species, while the lateralis system consists of open rather than enclosed pores. The caudal squamation is rather light, with scales present only on the basal third of the fin (de Soutter, pers. com.), a feature shared with only one other Malagasy congener. Radiographic examination of the caudal skeleton confirms Huber’s observation that a shallow notch separates the upper plate, formed by the fusion of third, fourth and fifth hypural bones and the lower plate, formed by the fusion of the first and second bones. This condition is more reminiscent of ZOOTAXA that found in many representatives of the Nothobranchidae (upper and lower plates separated by a deep groove), than that seen in Aplocheilus (hypural skeleton made up of three independent elements, the upper- and lowermost comprising the fused fourth and fifth and first and second hypural bones respectively). In the absence of additional material of P. nuchimaculatus, there is no way to determine whether the observed anomalies in squamation and caudal skeleton of the type specimen are idiosyncratic or reflect significant population-level differences. Pending the acquisition of additional material of this species, it seems advisable to follow Parenti (1981) and provisionally assign Poecilia nuchimaculata to the genus Pachypanchax OMO omalonotus OMO has been around a very long time but Loiselle when he went back to collect from the original collection point he found a different fish actually a new species he named ARN. OMO and ARN don't live anywhere near each other. PLA playfairii PTC patriciae SAK sakaramyi

SPK sparksorum VRT varatraza breeding care evolution

"The most primative of all killies they are in every sense of the word living fossils". - Paul Loiselle
Distribution in Madagascar

P. playfairi is from the Seychelles Islands which are just north of Madagascar the other species are all endemic to Madagascar.

Madagascar is a fragment of the southern tip of the ancient super-continent Gondwanaland that split off from continental Africa about 120 million years ago, India split off from this fragment 65 million years ago.

Completely isolated from all other life evolution slowed down as there were far fewer things to adapt to. The Pachypanchax that were in India where were the same as the ones in Madagascar before the split began changing in their new surroundings and became Aplocheilus while Pachypanchax still in Madagascar didn't really change.

The geography of Madagascar is fairly simple, it's a thousand miles long and there's mountains in the middle. The east coast is a permanent rain forest because of the moisture laden air blowing from the Indian Ocean. Bedotia are found here. The west cost is dry and sandy. Pachypanchax live here except for the one location where one species lives on the other coast.

Madagascar is home to the Tenerec, the insectivore that is the smallest mammal known and the most primitive of primates: the lemurs.

Or as Loiselle refers to them: "tree poodles".

I have a problem with the Lemurs, not that I do not like the Lemur, in fact I've never met a Lemur I didn't like, they're very amiable animals. But, mention you work in conservation in Madagascar and the first thing anybody says is "we have to save the Lemur". Well let me tell you something. Every Lemur known to science in 1900 is with us today and that is not true of the fish of Madagascar."

- Paul Loiselle

Two species of Pachypanchax seem to have gone extinct in the same time frame as have other Malagasy fish.

Aplocheilus Pachypanchax Upper Jaw: mobile immobile Haemal Arches: expanded unexpanded Hypural Bones: not fused fused Caudal: ovoid rounded Caudal Median Rays: prolonged not prolonged Caudal Base: unscaled 1/3 - 3/4 scaled Pineal Spot: present absent	Aplocheilus Photos roughly 5:2	Pachypanchax Photos roughly 5:3
Aplocheilus are just narrow Pachypanchax

"Myers (1933) based the genus Pachypanchax upon four diagnostic characters: (1) limited mobility of the maxilla, resulting from its attachment posteriorly by the skin to the postorbital region of the skull; (2) presence of unexpanded haemal arches; and (3) a rounded caudal fin whose (4) basal half is heavily scaled, the scales in straight rows, one scale wide, each series covering the interspace between two caudal rays. Myers placed particular emphasis on the caudal squamation of Pachypanchax, which he found to be unique among Old World aplocheilid cyprinodonts examined by him, and matched only by that of the Neotropical genus Austrofundulus."
Loiselle 2006

Thus Austrofundulus is another missing link, it has not yet evolved any further with regard to caudal scalation any more than the Pachypanchax it evolved from.

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Map from
From Loiselle 2006 -
"A review of the Malagasy Pachypanchax (Teleostei: Cyprinodontiformes, Aplocheilidae), with descriptions of four new species
by Paul V. Loiselle

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This shows the breakup of the Gondwanaland super-continent and the origin of Madagascar, India and the Seychelles where P. playfairi is the sole freshwater fish.

150 million years ago a piece the the Antarctic continenal mass split off.

120 million years ago it had totally separated from Antarctica.

105 mya and Africa and the Indian subcontinent moved north.

90 MYA was a big time for killies. By now the Indian subcontinent was at the equator. We believe the greatest amont of divestidicauton began about 80-90 mya. This is when modern killifish began to emerge. India and Magagascar split.

65 MYA ago. Magagascar and the Seychelles split.

50 MYA

Present day