Choisir une autre famille AcartiidaeAegisthidaeAetideidaeArctokonstantinidaeArietellidaeAugaptilidaeBathypontiidaeBoholinidaeCalanidaeCandaciidaeCentropagidaeClausidiidaeClausocalanidaeClytemnestridaeCorycaeidaeDiaixidaeDiscoidaeEctinosomatidaeEpacteriscidaeEucalanidaeEuchaetidaeEuterpinidaeFosshageniidaeGiselinidaeHyperbionychidaeKyphocalanidaeLubbockiidaeLucicutiidaeMecynoceridaeMegacalanidaeMegapontiidaeMesaiokeratidaeMetridinidaeMiraciidaeMisophriidaeMonstrillidaeMormonillidaeNullosetigeridaeOithonidaeOncaeidaePalpophriidaeParacalanidaeParalubbockiidaeParapontellidaeParkiidaePhaennidaePlatycopiidaePontellidaePontoeciellidaePseudocyclopidaePseudocyclopiidaePseudodiaptomidaeRataniidaeRhincalanidaeRidgewayiidaeRostrocalanidaeRyocalanidaeSapphirinidaeScolecitrichidaeSpeleoithonidaeSpeleophriidaeSpinocalanidaeStephidaeSulcanidaeTemoridaeThalestridaeTharybidaeThaumatopsyllidaeTisbidaeTortanidaeUrocopiidaeincertae sedis (Calanoida)incertae sedis (Cyclopoida)

Calanoida ( Ordre )

détails

    Arietelloidea ( Superfamille )

détails

 Abréviations ou symboles

issued from : S. Ohtsuka, H.Y. Soh & S. Nishida in J. Crustacean Biol., 1997, 17 (4). [p.589, Fig.8].
Cladogramm showing phylogenetic relationships between genera of the family Heterorhabdidae generated with PAUP when all characters are set unordered.
The numbers corresopnd to characters in Table 3 (following figure). Underline = multistate character; * = reversal; cross = convergence.
Diss = Disseta; Micr = Microdisseta; Meso = Mesorhabdus; Hets = Heterostylites; Hemi = Hemirhabdus; Neo = Neorhabdus; Hete (Para) = Heterorhabdus (Paraheterorhabdus); Hete (Hete) = Heterorhabdus (Heterorhabdus).

issued from : S. Ohtsuka, H.Y. Soh & S. Nishida in J. Crustacean Biol., 1997, 17 (4). [p.587].
Characters used in the cladistic analysis (in the matrix) for genera on the family Heterorhabdidae.
Codes 0-4 refer to transformation series of multistate characters. o = plesiomorphic state, 1 = advanced (apomorphic) state, 2-4 = further advanced states, 9 = missing data.

issued from : S. Ohtsuka, H.Y. Soh & S. Nishida in J. Crustacean Biol., 1997, 17 (4). [p.590, Fig.9].
Two cladograms showing phylogenic relationships between genera of the family Heterorhabdidae generated with PAUP when all characters are set-ordered.
The numbers, symbols, and abbreviated generic names as in Fig. 8 and Table 3 (above).
For the authors gut content analyses partly support Heptner's (1972) conclusion on the feeding habits of the family. The phylogenetic relationships among the genera of the family generated in the present study are almost identical with the noncladistic evolutionary tree of Hepner (1972), which was not based on detailed observations of the mandibular ventralmost teeth and the posterior surface of the labrum. The particle-feeder Disseta is the first to diverge from the main lineage, while the carnivores Hemirhabdus-Neorhabdus-Heterorhabdus are the terminal branch. Microdisseta is the second off-shoot in the evolution of the family. Mesorhabdus and Heterostylites are intermediate between these suspension feeders and the carnivores. The relative position of Heterostylites in the cladograms is equivocal.
The specialization of the mandibular ventralmost tooth and the supposed paralytic-substance-releasing gland openings on the labrum are shared by Heterorhabdus and the Hemirhabdus-Neorhabdus clade.
The evolutionnary transformation from particle feeders to pure carnivores has been accomplished by a combination of reductions or losses and specializations of several elements on the mouthpart appendages and the conversion of a lateral pair of labral secretory glands into a venom- or anaesthetic-realising system. Only in Heterorhabdus the relative elongation of the maxillary (Mx2) praecoxa is added to these transformations (length of Mx2 praecoxa in relation to body length female = 19.7). The elongation supposedly guarantees effective capture of prey animals (see in Ohtsuka, 1991). The remarkable elongation of the Mx2 praecoxa is found separately in Heterorhabdus and Heterostylites (ratio length of Mx2 praecoxa in relation to body length female = 14.4 in the latter) is not involved in the cladistic analysis.
The lateral pair of large gland openings (type-1) on the posterior surface of labrum of Hemirhabdus-Neorhabdus-Heterorhabdus seem not be novel structures, but a conversion of two outer pores of two pairs of openings of ancestral type-3 glands into type-1 gland openings. In Disseta, Mesorhabdus, and Heterostylites, which lack type-1 glands, there are two pairs of openings of type-3 glands of almost equal size, while in Hemirhabdus, Neorhabdus, and Heterorhabdus, which possess type-1 glands, there is only one pair of openings of type-3 glands. This interpretation is supported by the fact that both type-1 and type-3 glands have one-paired gland cells and a common opening (see in Nishida & Ohtsuka, 1996); the conversion may be accompanied by an increase in the size of the gland system and the lateral movement of the position of the openings.
In the Md, the reductions or losses of dorsal teeth and of daggerlike spinules have occurred throughout the evolution of the family. Heterostylites and Heterorhabdus may have independently developped the most advanced condition, the complete absence of these elements. The specialization of the ventralmost tooth and its isolation from the remaining teeth are evidently associated with the acquisition of the type-1 glands, and facilitate its protrusion from between the labrum and paragnath to inject a paralytic substance into prey (see in Nishida & Ohtsuka, 1996). The complete tubular structure of the ventralmost tooth of Heterorhabdus seems to be much effective in injecting a paralytic substance into prey than the semitube of Hemirhabdus and the groove of Neorhabdus. To avoid leaking the labral paralytic substance, the postrior side of the labrum presumably functions as an operculum to close the groove of Neorhabdus and the semitube of Hemirhabdus during injection of the substance into prey via the ventralmost mandibular tooth. The central teeth also appear to have become relatively elongate and slender in an evolutionary spep from Disseta to Mesorhabdus.
In the Mx2, the transformations in the family can be explained by both developments and reductions of elements. Two setae on the basis and the first endopod segment are highly specialized into a grasping organ in the carnivores, with heavy sclerotization of the setae with hooked tips and an inner row of stout spinules. Reductions of setae on the second to fourth endopod segments are exhibited by all carnivores. Similar specializations and reductions of the Mx2 elements have convergently occurred also in the deep-sea predatory family Hyperbionychidae (see in Ohtsuka & al., 1993).