Notes on the Osteology and Systematic Position of Hypoptychus dybowskii 
Steindachner and Other Elongate Perciform Fishes 1 
William A. Gosline 2 
Longer ago that can gracefully be admitted, 
Dr. Paul Kahsbauer of the Vienna Naturhis- 
historische Museum was kind enough to send 
me a specimen of Hypoptychus dybowskii from 
Steindachner’s (1880) original series taken off 
"Northern Japan.” Steindachner placed this fish 
alongside the Ammodytidae, and there has been 
a division of opinion ever since as to whether 
it should be included in or excluded from that 
family (cf, Regan, 1913; Jordan, 1923; Duncker 
and Mohr, 1939; Berg, 1940). In order to in- 
vestigate its relationships, the Vienna specimen 
has been stained and dissected, and its oste- 
ology compared with that of the ammodytids 
Bleekeria gilli (Fig. la) and Ammodytes tobi- 
anus. The specimen of Bleekeria is Hawaiian 
and was retrieved from tuna spewings. Am- 
modytes is represented by two series, sent to 
me from the U. S. National Museum and the 
Museum of Comparative Zoology through the 
courtesy of Dr. L. P. Schultz and Dr. G. W. 
Mead, respectively. 
That Hypoptychus belongs to the superfamily 
Ammodytoidae seems certain. The relationships 
of the superfamily Ammodytoidae are more 
obscure. A second objective of the present in- 
vestigation has been to look into this matter, 
and a preliminary discussion of certain of the 
problems involved here will serve as an intro- 
duction to the paper. 
In a typical percoid fish, e.g., Epinephelus, 
there are 24 vertebrae, and the dorsal fin is 
composed of an anterior spinous portion and a 
posterior soft portion. In such a fish the ma- 
jority of the basal supporting elements, i.e., 
pterygiophores, of the spinous dorsal have a 
one-to-one relationship with the vertebrae be- 
low them; the soft dorsal rays and their ptery- 
1 Contribution No. 1176 of the Hawaii Marine 
Laboratory and of the University of Hawaii Depart- 
ment of Zoology. Submitted July 25, 1961. 
2 Department of Zoology, University of Hawaii. 
giophores, in contrast, are more closely spaced so 
that there is more than one ray and pterygio- 
phore to each vertebra. Time and again, how- 
ever, the percoids and their derivatives have 
become elongate. This change in shape is fre- 
quently accompanied by a whole series of other 
alterations. Thus, the cranial crests become low 
or disappear, the number of vertebrae increases, 
the distinction between dorsal spines and rays 
becomes reduced, both types of dorsal (and 
anal) rays develop an approximately one-to-one 
relationship with the vertebrae, and the caudal 
fin becomes rounded and its principal rays re- 
duced in number. All of these changes are to be 
found among the percoids, e.g., the Cepolidae, 
trachinoids, ammodytoids, blennioids, schindler- 
ioids, and most gobioids. 
Indeed, it seems that all of these modifica- 
tions occur together in the majority of elongate 
percoid derivatives and that those forms, such 
as the ophidioids, where there is more than one 
dorsal and anal ray per vertebra are the excep- 
tion rather than the rule. On the other hand, 
the author is aware of no prepercoid teleost 
with a one-to-one relationship between soft dor- 
sal and anal rays and the vertebrae. If what 
has just been said is correct, it follows that any 
fish with such a relationship is a percoid deriva- 
tive, but that the unit correspondence between 
soft rays and vertebrae is of little use in dis- 
tinguishing the various lineages of percoid der- 
ivation. 
Here, the schindlerioids and gobioids will be 
dismissed from further consideration, as each of 
these groups has peculiarities by which it may 
easily be defined. However, Hawaiian specimens 
of the trachinoids Parapercis schauinslandi (Par- 
apercidae, Fig. 1 c) and Crystallodytes cookei 
(Trichonotidae, Fig. lb), and of the blennioid 
Tripterygion atriceps ( Tripterygiidae, Fig. Id) 
have been stained and dissected. These speci- 
mens will be used both for purposes of com- 
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