Bairdiella ronchus

Super Group: 
Opisthokonta
Phylum: 
Chordata
Sub-Phylum: 
Vertebrata
Class: 
Actinopteri
Order: 
Perciformes
Sub-Order: 
Percoidei
Family: 
Sciaenidae
Genus: 
Bairdiella
Species: 
ronchus
Authority: 
Cuvier 1830
Synonym(s): 
Corvina ronchus (Cuvier 1830)

Diagnosis

Diagnosis_Genus: Bairdiella Gill. Body oblong, compressed, with the dorsal outline rapidly descending in a nearly straight line from the dorsal fin, and with the abdominal outline nearly straight. Head compressed, conical, with the muzzle scarcely convex, and with the lower jaw ascending. Mouth terminal and oblique. Supramaxillary bones mostly exposed, and ceasing under or slightly behind the pupil of the eyes. Preoperculum with no distinct crest; its posterior margin and rounded angle denticulated, the teeth increasing in size towards the angle. Two lateral pores of each ramus of the jaw small; the two symphyseal ones rudimentary. Anterior row of stout and recurved conical teeth in each jaw, behind which, in the upper, is a narrow band of villiform ones. Anterior dorsal fin sustained by nine or ten spines. Anal fin with the second anal spine more than two-thirds as long as the longest branched ray. Caudal fin subtruncated. Lower pharyngeal bones combined form a lanceolate, or very deeply ex-cavated triangle ; each separately is semi-claviform. Their upper surface is covered with small teeth, and along the internal margin with a row of scarcely recurved more elongated ones. The upper pharyngeals are also clothed with small teeth, besides which, on the median bone, are conical ones like those of the lower bones. The first branchial arch is externally furnished with compressed setae, which are muricated on their internal borders; internally, they have transverse thick ridges with villiform teeth, like those of the other arches ; the external rows of ridges are larger than the internal. The scales of this genus are arranged in much less oblique lines than in most of the other representatives of the subfamily of Sciaenidae. An oblique row in the typical species extends from the commencement of the second dorsal to that of the anal. This genus has been established for the Perca argyroleuca of Dr. Mitchill, or the Corvina argyroleuca of Cuvier and Valenciennes, and the allied species chiefly found in the Caribbean and neighboring seas. The Homoprion xanthurus of Holbrook, or Homoprion subtruncatus, perhaps belongs to this genus also, but as it is said to have " two or three series of small, pointed, recurved, cardlike teeth, with an outer row of larger, conical, pointed teeth" in both jaws, it is not deemed advisable to positively place it there. The specimens referred to under that name by Dr. Girard, in the "Report on the Ichthyology of the Mexican Boundary Survey," as preserved in the Smithsonian Institution, belong to the Bairdiella argyroleuca. We have examined five of the specimens labelled as Homoprion xanthurus, and have counted the number of rays of the second dorsal fin. There are one spinous and twenty or twenty-one articulated rays, the last of which is double. They therefore agree in the number of rays, as well as in appearance, with the Bairdiella argyroleuca. The Homoprion subtruncatus has thirty-two articulated dorsal rays. A variation equalling a third of the greatest number of rays is rarely found in the same natural genus. Yet there is a very close resemblance between that species and the type of Bairdiella. It certainly shows much more affinity to the latter externally than to the Homoprion lanceolatus. This genus is less nearly allied to Corvina; it differs in form, squamation and the dentation of the margin of the preoperculum. The genus Stellifer of Cuvier is founded on the Bodianus stellifer of Bloch, a species supposed to belong to this group, but which cannot be positively identified.

Diagnosis_Species: Corvina ronchus Cuvier. This species is much look like the previous one (Corvina argiroleuca), especially by the teeth that arm its preopercle. Two or three of the angle, and especially the third are high: it is directed downward and a little forward; but the anal spine is much higher, as much as in the corb solado. The fin is a little cut in the wrong. D. 10 - 2/23 ou 24; A. 3/8; C. 17; P. 18; V. 1/5. We have individuals from six to eleven inches in length. The liver of Corvina ronchus is very small. The stomach forms a sharped cul-de-sac, long enough and with pretty thick walls. The esophagus is short. The ascending branch fits almost under the diaphragm and it is very short. There are six short and slender ecoecums. The intestine, with is also very narrow, has only two mediocre folds. The swim bladder is large, elongated, scalloped forward, pointed backward, she has no horns. The protruding and spare arcades of his skull are not very numerous, and it is moderately curved below. The terraced ridge of the occiput is considerable and reinforced by two lateral and longitudinal edges. There are twenty-four vertebrae. The first interspinous anal attaches to the eleventh, and eventually far behind. There are three interspinous without rays before the ridge.

Body_adults_length_mean: 25 cm
Body_adults_length_max: 35 cm
Body_larvae_length: 2.29-4.66 mm (estuarine system, Porcaro et al., 2014)
Body_juvenile_length: < 15.8 cm (Fishbase)
Sequence_16sRNA: JX903962, KJ907197, KJ907198, KJ907199 (Barbosa, 2014)
Sequence_COI: KJ907229, KJ907230, KJ907231, KJ907232 (Barbosa, 2014), JK903995 (Santos et al. 2013)
Sequence_TMO-4C4: JX904028, KJ907267, KJ907268, KJ907269 (Barbosa, 2014)
Sequence_RHOD: KJ907299, KJ907300, KJ907301, KJ907302 (Barbosa, 2014)
Sequence_RAG-1: KJ907335, KJ907336, KJ907337 (Barbosa, 2014)

Type species

The type species of the genus Bairdiella is Bodianus argyroleucus (Mitchill, 1815).

Ecology

Bairdiella ronchus lives in Western Atlantic: Caribbean Sea southward to Brazil (Fishbase).
Habitat: estuarine
Substrate: water
Salinity: marine
Salinity: brackish
Depth: 16-40 m (Fishbase)
 

Life cycle

This species has a very short life; only a few individuals, 3.5% of the population, exceed the age of 2 years and only 0.7% attained 3 years (Louis 1985). Bairdiella ronchus is an heterochronous species whose reproductive cycle lasts 8-9 months. The breeding season is from March to October with three peaks of maximum reproductive activity in March, May and September-October (Louis, 1985).
There is no sexual dimorphism.
Longevity: 1-3 years (Louis, 1985)
Reproduction_mode: sexual (oviparous)
Fertility_period: seasonal (spring to summer) (March to October in Guadeloupe, Louis, 1985)
Spawning_method: external fertilization in the water column

Feeding behaviour

Carnivorous

Mode of locomotion

Motility: motile_swimming

Reference(s)

Observation site(s)

SYMBIONTS

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Association with... Region origin Name of site In reference...
Amyloodinium ocellatum Laguna de la Restinga