Tuesday,17 September 2019, 6 : 52 PM

Ptychochromis loisellei

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Ptychochromis loisellei
Image Credit: Melanie L.J. Stassiny

Introduction



Ptychochromis loisellei is a medium sized fish which is commonly found in its limited range situated in Maharana river and its tributaries in North eastern Costal Madagascar.


Taxonomy

(Click for details of Cichlid taxonomy)

Ptychochromis loisellei was first described by Stiassny & Sparks , in 2006.
The genus Ptychochromis was described by Steindachner in 1880.
The species name loisellei after Paul V loisellei, who collected the type series and in recognization of his many contributions to understanding and conservation of Madagascar fresh water fish.



Description

Ptychochromis loisellei reaches a standard length of about 3.9 ".
Body is moderately deep and laterally compressed.
Body depth is approx 45% of SL.
Snout outline is markedly pointed.
Lateral snout outline is straight to moderately curved.
Predorsal head profile is moderately convex from middle of eye to dorsal-fin origin.

Dorsal body profile from dorsal-fin origin is moderately curved.
Ventral(lower) body profile is straight.
Caudal peduncle is short, deep, and laterally compressed.
Dorsal-fin origin is located anterior to vertical through pectoral-fin insertion.
Pelvic-fin origin is located well posterior to vertical through pectoral-fin insertion.
Total vertebral count is 27 or 28, with 13 vertebra located on body and 13-14 located on caudal region.
Lower and upper jaws are similar (isognathous), in some cases the lower jaw can protrude slightly.
Teeth in jaws are bilaterally symmetrical and bicuspid, with crowns some what expanded distally and slightly recurved.
Outer row teeth of both jaws are enlarged and graded in size laterally.
Like all cichlids, P. loisellie have pharyngeal teeth.
Upper and lower pharyngeal tooth plates are well developed with strong teeth.
Body is covered with large, regularly imbricate, ctenoid scales from about level of mid orbit to proximal portion of caudal fin.
Scales above upper lateral line to about level of origin of soft dorsal fin are cycloid.
Scales on flanks becoming increasingly ctenoid posteriorly, but at most only weakly so.
Scales on nape are ctenoid, rest of scales in head region are cycloid.
There are 3-4 rows of cycloid scales on cheek.
Scales in front of chest and belly are cycloid, scales towards back of chest are ctenoid.
Scales on opercle and subopercle cycloid or weakly ctenoid.
Anterior chest scales are reduced in size and embedded.
Snout, and region near eyes does not have any scales.
Scales on caudal fin reduced in size,ctenoid anteriorly and much smaller and cycloid posteriorly.
Lateral line has 28 or 32 scales.
There are five scales in diagonal from lateral line to dorsal-fin origin.
There are four or five scale rows between bases of pectoral and pelvic fins.
No scale rows present along dorsal- and anal-fin bases.
Dorsal fin is placed vertically above pectoral fin base, slightly anterior and has XIII to XIV spines, 12-13 soft rays.
Anal fin has III spines and eight or nine soft rays. First anal spine is very short, second and third spines elongate and of similar length.
Caudal fin is slightly indented (emarginate), trailing margins of upper and lower lobes quite produced.
Pectoral fin is elongate and tapered distally.
Distal margins of soft dorsal and anal fins produced and markedly pointed in larger specimens.
Trailing margin of soft dorsal fin elongate and filamentous.
Pelvic fins are short, and extend to origin of anal fin.



Distribution & Habitat

Ptychochromis loisellei is known only from Maharana river and its tributaries in North eastern Costal Madagascar.

Habitat :



Colouration





Conservation Status & Threats



IUCN lists this as an un described species with voucher specimens held at MNHN. The fish is found in limited range in Tributaries of maharana river near town of Antsirabe-Nord. Its extant of occurrence is less than 5000 sq km, and area of accupancy is less than 500 sq m. The main impacts thought to have caused the decline of this species are deforestation leading to loss of habitat through increased sedimentation, competition from introduced tilapia and overfishing. This species is assessed as Endangered.
Major Threats:



Tank Size and setup:


No information was available regarding its upkeep in aquariums.

Species Snapshot

Species Card


Particulars Details
Scientific Name Ptychochromis loisellei
Common Name Garaka
Genus Ptychochromis
Subfamily Ptychochrominae
Geographical Origin Africa: Madagascar.
Diet
Gender Differences
Breeding
Temperament
Con Specific Temperament
Water hardness
Difficulty Level in Aquariums


Morphometric Data


Particulars Details
Total Length(inches)
Standard Length(inches) 3.90

Measurements as % of Total Length


Particulars Details
Body Depth 44.90 %
Head length 34.00 %
Pre Dorsal length 28.30 %
Pre Pectoral length  %
Pre Anal length 72.00 %
Pre Pelvic length 40.10 %
Caudal Peduncle Depth 17.70 %
Caudal Peduncle Length 14.50 %
Fork length  %
Length of Last Dorsal Fin Spine  %
Pectoral Fin Length 31.70 %
Pelvic Fin Length 32.10 %

Measurements as % of Head Length


Particulars Details
Head Width 16.50 %
Snout length 40.20 %
Eye diameter 28.70 %
Pre Orbital Length 22.80 %
Inter Orbital Width 29.90 %
Pre Orbital Depth 22.80 %



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