Sunday,21 January 2018, 6 : 36 AM    

IUCN Freshwater Fish Specialist Group- Madagascar Chair

 

 
Library > Cichlids > General Articles > Taxonomy of Cichlids > Sub Family Ptychochrominae > Genus Ptychochromis
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Genus Ptychochromis
       
Scientific classification
     
Kingdom : Animalia
Phylum : Chordata
Class : Actinopterygii
Order : Perciformes
Suborder : Labroidei
Family : Cichlidae
Sub Family :
   
Subfamilies

Introduction

Ptychochromis is a genus of cichlids endemic to rivers and lakes in Madagascar.

These are restricted to lakes and rivers in Madagascar, and the majority are threatened.

Taxonomy

The genus was described by Steindachner in 1880.

However an exhaustive study was made by John S Sparks and Smith in 2004.

They considered 21 morphological features considered analysis of 4 gene fragments.

Description

Stiassny and Sparks described the genus in details in a paper in 2006.

Some of the major features of this genus are

Configuration of median frontal pores:

All cichlids have sensory pores around central sensory line on their head.

These are either grouped around the middle or can be set apart.

The sensory pores of cichlids belonging to genus Ptychochromis are setup very far apart.

 

Tooth Form :

All cichlids in this genus have bicuspid teeth ( having two points.
These are set in a bilateral symmetrical shape in the jaw.

 

Anterior dorsal-fin

There is well developed pro current spur on the first dorsal fin.

This feature is also found in South American genus Gymnogeophagus.

 

Supra neural shape:

The supra neural bone is in shape of inverted L.

This feature is more marked in first supra neural bone, the second supra neural bone is more recurved in shape.

 

Anal Spines :

The first anal spine is extremely short while succeeding two spines are long and more or less same in length.

 

Shape of inner margin of the fourth ceratobranchial

The fourth ceratobranchial is these cichlids has a characteristically elongate process and has deeply rounded indentation on its inner margin.
These feature is also shared by genus katria.

 

Enlarged latreosensory Canals :

Sensory canals which are placed laterally on head ( neuro-cranium,preopercle and mandible) are enlarged and sensory pores are markedly expanded.
This trait is also seen in closely related genus Katria and non ptychochorminae genus Heterochromis.

 

 

 

Supra neural pattern:

Cichlids of this genus have the two Supra neural elements placed before First neural spine.

In all other genus with two supra neural elements are separated by an intervening spine.

This trait is also seen in closely related genus Katria.

 

Lateral ethmoid process of the palatine:

The palatine bone of Ptychochromis bears a well developed, expansive, and dorsally elevated lateral ethmoid process on the dorsal margin of the palatine head.
There is a broad articulation surface on the medial face.

 

Free second epibranchial tooth plate:

Cichlids belonging to genus Ptychochromis have a free second epibranchial tooth plate.
This feature is not found in other closely related genus like Katria or Oxylapia.

 

Palatine type

The palatine bone in Ptychochromis shows two distinct morphology.

The first one is referred as "Western type" which has a has a compact palatine head and the ethmoid process is elevated and has a upright orientation.

The second one is referred as "Eastern Type" which has an elongate palatine prong and a markedly horizontal orientation, also the ethmoid process is less prominent.

 

Ctenoid Scales :

Ptychochromis have ctenoid scales. Ctenoid scales have small spine like projections at one side of scale called cteni.
They have weak cteni, although two species P. insolitus and P.inornatus have extremely developed cteni.

 

Distribution & Habitat:

Cichlids of genus Ptychochromis were widely distributed in fresh waters throughout much of northwestern, southwestern,and eastern Madagascar .

However, recent surverys indicate that populations throughout the island, especially in the south western and north western regions, have become increasingly rare and highly restricted in distribution or, in the case of the south western Onilahy drainage population,may have become extinct .

 

SPECIES:

At present 9 species are recognized in this genus.

 
         
SPECIES SNAPSHOT
 
     
Scientific Name :
Ptychochromis onilahy
   
Common Name :
Origin :
Africa: Madagascar.,Other African,AFRICA
Habitat :
benthopleagic: Freshwater: Brackish
Diet :
Breeding:
Standard Length: 3.1 "
Total Length:
   
   
   
     
     
Scientific Name :
Ptychochromis makira
   
Common Name :
Origin :
Africa: Madagascar.,Other African,AFRICA
Habitat :
benthopleagic: Freshwater: Brackish
Diet :
Breeding:
Standard Length: 5.2"
Total Length:
   
   
   
     
     
Scientific Name :
Ptychochromis loisellei
   
Common Name :
Garaka
Origin :
Africa: Madagascar.,Other African,AFRICA
Habitat :
benthopleagic: Freshwater: Brackish
Diet :
Breeding:
Standard Length: 3.9"
Total Length:
   
   
   
     
AUTHOR    
Sandeep Raghuvanshi    
     

REFERENCES

   
Froese, R. and D. Pauly. Editors: Fishbase, World Wide Web electronic publication.www.fishbase.org, version (10/2013),2013, ISBN :
ITIS: Integrated Taxonomic Information System, http://www.itis.gov,, ISBN :
Melanie L.J. Stassiny, John S. Sparks: Phylogeny and Taxonomic Revision of the Endemic Malagsy Genus Ptychochromis with the description of Five New species and a Diagnosis for Karia, New Genus,2006,American Muesum of Natural History ISBN :