Leptocardii |
Not assigned |
Branchiostomatidae
Environnement : milieu / zone climatique / profondeur / gamme de distribution
Écologie
Benthic; profondeur 229 - ? m (Réf. 766). Deep-water
Northwest Pacific: Japan.
Longueur à la première maturité / Taille / Poids / Âge
Maturité: Lm ? range ? - ? cm
Description synthétique
Morphologie
Body, 14.7 mm long and up to 1.5 mm high, elongated longitudinally and much flattened laterally, tapering gradually towards both ends; preatrioporal region 10.9 mm, atriopore to anus 1 .0 mm, postanal 1.8mm, and urostyloid process 1.0 mm. Rostral fin extensive and semi-circular, clearly separable from other part by dorsal
and ventral notches. Dorsal fin very low in anterior two-thirds of body, while becoming much higher posterially. Left metapleuron terminated abruptly and markedly just behind atriopore, while the right confluent with well-developed ventral fin, followed by thin and high caudal fin, somewhat higher than dorsal fin. Urostyloid process separable from dorsal and caudal fins by its own lower dorsal and ventral fins. Dorsal fin-chambers 270, relative length to width for posterior tall ones up to 3.3; preanal fin-chambers indiscernible, but instead, an elongated vacuole detected along ventral side of rectum between atriopore and anus. Myotomes 83 in total, consisting of 58 in preatrioporal region, 9 in region from atriopore to anus, and 16 in postanal, thus giving the myotome formula of 58+9+16=83. A black pigment spot detectable in neural tube just anterior to first myotome. Tentacular ring composed of Ca. 30 tentacles (including a few dorsal-most minute ones), its anterior margin situated at level of axial (=proximal) part of 5th myotome; intertentacular membrane extremely higher in span of 6 tentacles next to much shorter midventral tentacle than elsewhere. Mid-gut coecum elongated, ranging at level from 20th to 48th myotomes. No gonad.
Cycle de vie et comportement reproducteur
Maturité | Reproduction | Frai | Œufs | Fécondité | Larves
Members of the class Cephalochordata are gonochoric. Life cycle: Eggs develop into planktotrophic larva and later on to benthic adults.
Nishikawa, T. 2004 A new deep-water lancelet (Cephalochordata) from off Cape Nomamisaki, South West Japan, with a proposal of the revised system recovering the genus Asymmetron. Zoological Science 21:1131-1136. (Réf. 766)
Statut dans la liste rouge de l'IUCN
(Réf. 130435: Version 2025-2 (Global))
statut CITES (Réf. 108899)
Not Evaluated
Not Evaluated
Menace pour l'homme
Harmless
Utilisations par l'homme
FAO - Publication: search | FishSource |
Outils
Plus d'informations
Écologie trophiqueAliments (proies)
Composition du régime alimentaire
Consommation alimentaire
Prédateurs
Dynamique des populationsCroissance
Âges / tailles maximales
Longueur-poids rel.
Rel. longueur-longueur.
Fréquences de longueurs
Conversion de masse
Abondance
Cycle de vieReproductionMaturitéFéconditéFraiŒufsDéveloppement de l'œufLarves PhysiologieConsommation d'oxygène
Liées à l'hommeTimbres, pièces de monnaie, divers
Sources Internet
Estimations basées sur des modèles
Vulnérabilité de la pêche
(Réf. 71543) |
(0 of 100). |
Catégorie de prix
(Réf. 80766): |
Unknown. |
