Morphology of the buccal apparatus and related structures in four species of Carapidae

Abstract

The aims of this study were (1) to compare the morphology of the buccal apparatus, the suspensorium and the opercle in four species of Carapidae (Carapus acus, Encheliophis boraborensis, Encheliophis homei and Encheliophis gracilis) and (2) to investigate the relationships between their cranial anatomy, their carnivorous diet, and their well known ability to enter holothurians. The complex and strong dentition and the wide hyomandibular with thickenings that seem to suit the constraints of the adductor mandibulae muscles partly inserted on the neurocranium are signs of a carnivorous diet. C. acus, E. boraborensis and E. homei have extremely strong buccal pieces and can protrude their upper jaws. However, in E. gracilis, the jaws are more slender, and the insertions of the A 1 along the entire length of the maxillary associated with the lack of mobility between the maxillary and the premaxillary prevent buccal protrusion. These differences could be related to the diet: C. acus, E. boraborensis and E. homei can feed on fishes and crustaceans, whereas E. gracilis feeds only on holothurian tissue. The cephalic morphology of the four species is not incompatible with entering the host. However, the neutralisation of the suboperculum spine by ‘cartilaginous’ tissue could be considered to be a particular adaptation to this behaviour.

Unique morphologies of Encheliophis vermiops (Carapidae) with revised diagnosis of the genus

“…As in other Encheliophis, E. vermiops has a uniserial set of teeth on the jaws and displays no wide mouth opening because of the lack of mobility between the maxillaries and premaxillaries and the insertion of the adductor mandibulae A 1 directly on the premaxillary. The adductor mandibulae A 2 appear to be even less developed, and it was not possible to discern different bundles, as is the case in other Carapini species (Parmentier et al 1998). These characters support the parasitic lifestyle of E. vermiops.…”

“…In all other Encheliophis (and Carapidae) in which this character has been examinated, the anterior insertion of this muscle is usually on the orbital roof, on the inner face of the frontal (Parmentier et al 2002). In Carapini, the distinction between commensal species (Carapus) and the parasitic species (Encheliophis) has been corroborated by comparisons of their morphological features (Parmentier et al 1998(Parmentier et al , 2000Parmentier and Das 2004). The Carapus species have retained an apparatus enabling them to grasp and retain hard and elusive prey: strong jaws, high coronoid processes, a considerable dentition, a slight protraction of the upper jaws, the capacity to open the mouth wide and the presence of well-developed adductor mandibulae (Markle and Olney 1990;Parmentier et al 1999Parmentier et al , 2000.…”

“…5245) and paratype (AMS IB. The cephalic morphology of the genus Encheliophis has been thoroughly described by Markle and Olney (1990) and by Parmentier et al (1998Parmentier et al ( , 2000. The sound-producing apparatus is described in detail in Parmentier et al (2003).…”

“…The species that belong to the genus Encheliophis are parasites of holothurians (Parmentier et al 2000;Parmentier and Das 2004). Encheliophis is diagnosed by 11 autapomorphies (Parmentier et al 2000), among which are two characters easily observable in the field: the maxillaries and premaxillaries are united by short connective fibres to function as a unit, and both elements are bound to the skin, preventing a large gape (Parmentier et al 1998). Five Encheliophis are recognised: Encheliophis gracilis (Bleeker 1856), Encheliophis sagamianus (Tanaka 1908), Encheliophis vermiops Markle and Olney 1990, Encheliophis vermicularis Müller 1842, and Encheliophis chardewalli Parmentier 2004.…”

HSV (Herpes Simplex Virus)

“…De telles associations sont courantes entre poissons et gastéropodes (Parmentier et al, 1998 ;Hamel et Mercier, 1999 ;Flammang et al, 2002) et entre crustacés et bivalves (Takeda et al, 1997 Les Pseudomonas pourraient aussi favoriser dans le lait la croissance de pathogène humain comme Staphylococcus aureus (Seminiano et Frazier, 1966). Dans le poisson fumé avarié, une baisse de la concentration en oxygène par certaines bactéries Gram-négatives permettrait la croissance de bactéries anaérobies strictes tel que Clostridium botulinum (Huss et al, 1979).…”