MULLIGAN ET AL.: OTOCONIA FROM FOUR NEW ZEALAND CHIMAERIFORMES 



A dense aggregation of otoconia occurred 

 within tiie otoliths oi Rhinochimaera sp., each 

 otoconia having a distinctive pockmari^ed sur- 

 face topogi'aphy (Fig. 3A). Surface otoconia (see 

 Figure 2A) lacked these pockmarked features. 

 At high magnifications, the pockmarked surface 

 could be seen more clearly (Fig. 3B). In some 

 cases the pockmarks resulted in enough material 

 being removed from the surface to show that 

 otoconia were deposited as layers (Fig. 3C). A 

 few otoconia showed small (- 1 ixm) spherules on 

 their surface and some indications of fusion of 

 the spherules into a distinct layer (Fig. 3B, D). 

 Broken otoconia showed the expected epitaxial 

 growth of crystals from a central point. The 

 growth of individual otoconia appeared to be 

 parallel to that of the otolith: small spherules (== 1 

 |jLm) continued to grow (1 ixm) and progi'essively 

 fuse into larger otoconia, which in turn fused to 

 the form of the otolith itself (Fig. 3E). 



The otoconia from H. novaezelandiae had a 

 greater size range than those of Rhinochimaera 

 sp. and H. raleighana and were more oval in 

 shape. Although small (- 1 |j.m) spherules oc- 

 curred on the surface of otoconia, they did not 

 assume the more coordinated, layered appear- 



ance seen on the otoconia from Rhinochimaera 

 sp. and may have represented recrystallization. 



At similar magnifications to Rhinochimaera 

 sp. and//, novaezelandiae, individual otoconia of 

 H. raleighana showed a smooth and unifoiTn sur- 

 face. However, numbers of small crystals with 

 variable shapes were commonly found in the 

 otoconial mass of H. raleighana. Among these 

 crystals were many rod-shaped and twinned 

 rod-shaped crystals, some of which had small, 

 surface recrystallizations on them (Fig. 4A). 

 Crystalline aggregations occurred amongst the 

 H. raleighana otoconia, which had the appear- 

 ance of being part spindle-shaped ai'agonite 

 crystal, part aragonite spherule, and part fused 

 rod-shaped crystal (Fig. 4B). 



The majority of otoconia observed from 

 Chiniaera sp. were regular spheres. On closer 

 examination, the surfaces of Chitnaera sp. 

 otoconia varied from smooth to crystaUine, and 

 some otoconia surfaces exhibited a highly tex- 

 tured, irregularly crenellated surface (Fig. 5A). 

 Deposits of irregularly formed otoconia occurred 

 in Chiniaera sp.; they were marked by the ab- 

 sence of any readily observable matrix binding 

 and by the appearance of partially eroded 



Figure 3A. — Otoconia from Rhinochimaera sp. have a distinctive pockmarked appearance, that shows possible 

 points of adhesion (closed arrows) and other occurrences on the surface of the otoconia (open arrows) Bar = 

 0.1 mm. 



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