51813_Sturgeon biodioversity an.PDF

Figure 13. Map of eastern Europe and Asia showing a region of high diversity for Acipenseridae. Three of the f our extant genera ...

Figure 15.Color photograph of an aquarium specimen of the large Amu-Darya shovelnose sturgeon, Pseudoscaphirhynchus kaufmanni. T ...

Figure 17.Preliminary cladogram of acipenseriform interrelationships. Character numbers correspond to Tables 6 and 7. Arrangemen ...

ter populations (e.g., A. fulvescens Vladykov & Greeley 1963, A.baeriiin Lake Baikal, Ruban 1997 this volume). while stocks ...

certainly warrants much additional systematic re- come extinct in the recent decades, and the third search. One important point, ...

Pseudoscaphirhynchusare available in systematic collections outside Russia and Uzbekistan, and there has never been a modern spe ...

Figure 19. Lateral views of the opercular series of four taxa of Acipenseriformes to show loss of the opercle in Acipenseroidei ...

Character 3. Body scaling reduced to tiny isolated elements or absent This character was defined by Patterson (1982), noted by G ...

Figure 20. Scanning electron micrographs of Polyodon spathula larva: a -Lateral view of the head. The infraorbital lateral line ...

Grande & Bemis 1991) have regarded the bone on the leading edge of the upper jaw of Acipenseri- formes as homologous to the ...

atic because acipenseriform larvae and juveniles possess jaw teeth. Figure 20 shows the oral region of a Polyodon larva, with tw ...

posterior tips. This condition also occurs in †Sti- chopterus. Specimen based study is needed before proposing it as a synapomor ...

defining Acipenseroidei, which we modify and sup- plement here. Character 14. Loss of opercle This character was defined by Gran ...

morphic features because the bones more or less closely ensheath the underlying endochondral ros- trum. For now we accept these ...

other Acipenseriformes, is present in all Acipense- riformes (character 8, above), but the fan of rod- like ossifications in com ...

Character 26. Pectoral fin spine The presence of a pectoral fin spine was accepted by Grandc & Bemis (1991, character 13) as ...

Figure 22. Functional morphology of jaw projection in a juvenile white sturgeon, Acipenser transmontanus. In the photograph, an ...

Figure 23. Functional morphology of feeding in North American paddlefish, Polyodon spathula. The top photograph shows a juvenile ...

acter 15). One to three branchiostegals are present in Acipenseridae. whereas there is consistently a single branchiostegal in P ...

Feeding systems, jaw protrusion and ram ventilation The feeding system derived for all Acipenseri- formes is based on a jaw proj ...