Taxonomy

Chaudhuria ritvae has an elongate, eel-like body with greatest depth at the dorsal-fin origin.

Features include:

  • the body is anteriorly round in cross-section and laterally compressed in the caudal region
  • the head is elongate and cylindrical
  • it has small eyes, situated dorsolaterally in the anterior third of head, covered by skin
  • the mouth is terminal
  • the snout is short and rounded
  • the  tube of the anterior nostril is short, situated at the tip of snout and projecting slightly from it
  • lips are fleshy and well-developed on upper and lower jaws
  • the postorbital part of the head is elongate, with 6 long branchiostegal rays supporting prominent gill membrane covering the base of the pectoral fin
  • scales and lateral line canals are absent, therefore myomeres and myosepta along the body are visible

Dorsal and anal fins are long and separate from the caudal fin, and have the following:

  • dorsal-fin rays: 40–43
  • anal-fin rays: 40–43
  • caudal-fin rays: 4+4
  • pectoral-fin rays: 7–10
  • pelvic fin absent

The fish has 74–76 vertebrae, comprising 27–28 abdominal and 46–49 caudal vertebrae:

  • the neural arches of vertebrae are without any fenestration, but show small round depressions or openings
  • abdominal vertebrae have median triangular process of membrane bone coming off the roof of the neural arch
  • there are well-developed stout ribs on vertebrae 4-26, 4-27, or 4-28
  • the first dorsal-fin pterygiophore is inserted behind neural spine of vertebra 25 or 26, and last dorsal-fin pterygiophore is inserted behind neural spine of vertebra 66, 67 or 68
  • anal-fin pterygiophores are in front of first haemal spine 2 or 3
  • last anal-fin pterygiophore is inserted behind haemal spine of vertebra 67 or 68

Colouration

The body of the fish is light cream when preserved in alcohol, with numerous minute black spots on head, and sparsely scattered minute spots along the body. All median fins and pectoral fins are unpigmented and translucent.

Look-alikes

The 3 described species of the genus Chaudhuria look alike at first glance, but are distinguishable in a number of ways.

Chaudhuria ritvae differs from C. caudata as it has:

  • a greater number of caudal vertebrae (46–49 vs 42–45)
  • a smaller mouth with the posterior angle of the lips situated front of vertical through anterior margin of posterior nostril
  • broad and large ribs
  • neural arches of vertebrae without fenestration
  • no spots associated with base of dorsal and anal fin rays
  • sparse body pigmentation, consisting of only minute widely separated melanophores - in C. caudata body pigmentation is well-developed with numerous densely distributed melanophores that form lines or blotches
  • absence of pigmentation along pectoral-fin rays

Chaudhuria ritvae differs from C. fusipinnis in the following ways:

  • dorsal and anal fins separate from the caudal fin
  • a smaller number of dorsal- fin rays (40–43 vs 44–48)
  • a smaller number of anal-fin rays (40–43 vs 44–48)
  • a greater number of caudal-fin rays (4+4 vs 3+3)
  • teeth on hypobranchial 3
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Glossary
Branchiostegalrays

Elongate bones that support the gill membrane.

Ethmoid

The ethmoid bone in the skull separates the left and right nasal cavities.

Fenestration

Holes or openings.

Melanophores

Pigment cells containing a black pigment, melanin, that appears brown or black.

Myomeres

Short bundles of muscle fibres.

Myosepta

Thin layers of connective tissue that separate myomeres.

Pterygiophores

Fin supports. A series of bones with which the fins articulate and are further attached by muscle.