Herman, J.

Stehmann, M.

Open Marine Archive

BULLETIN DE L'INSTITUT ROYAL DES SCIENCES NATURELLES DE BELGIQUE, BIOLOGIE, 57: 41-42, 1987 
BULLETIN VAN HET KONINKLIJK BELGISCH INSTITUUT VOOR NATUURWETENSCHAPPEN. BIOLOGIE, 57: 41-42, 1987 
Contributions to the study of the comparative morphology of teeth 
and other relevant ichthyodorulites in living supraspecific taxa 
of Chondrichthyan fishes* 
Editor: M. STEHMANN 
General introduction 
by J. HERMAN 
The main aim of this series is to present a large variety 
of photographic material with very concise comments 
only. It will include several fascicles, which will deal 
with three subdivisions: Selachians, Batoids and Chi-
maeroids. 
The order of publishing the consecutive fascicles will 
depend on the completion of the scanning pictures. 
Each fascicle will deal with one or more families, 
eventually with a whole order, but they will not neces-
sarily appear in systematic order. 
In addition to the oral teeth the other ichthyodoruUtes 
of the Batoids and Chimaeroids, such as spinules, 
thornlets, and thorns will also be presented. 
The systematic concepts of the following authors will 
be considered: A.J. BASS, J.D. d'AUBREY & N. KlST-
NASAMY, H . B . BIGELOW & WC SCHROEDER, J. 
CADENAT, L . J . V . COMPAGNO, G . DINGERKUS, 
J.A.F. GARRICK, G . KREFFT, J.D. MCEACHRAN, 
S. SPRINGER, M . STEHMANN, J . H . WALLACE. 
PART A: SELACHII 
The Selachian micro-teeth of one representative per 
supraspecific taxon, that have not been fully studied 
yet, will be figured and described. The large teeth of 
which an abundant iconography exists, will be des-
cribed as concisely as possible. 
An odontological systematic will be proposed in the 
form of identification keys that include both large and 
micro-teeth. 
For each taxon, a series of scanning pictures will illus-
trate the different characteristic forms of teeth in func-
tion at their position in the jaws (symphysis, anterior, 
lateral, commisural, upper and lower...), and an even-
tual sexual dimorphism. 
' This series is dedicated to the memory of Dr E CASIER (1904 -
1976). 
As far as possible the teeth of mature specimens of 
medium size of the supraspecific taxon concerned, 
were selected, as they are most typical. 
Whenever different types of tooth morphology are 
observed among the species of a genus (e.g. Triakis), 
not only teeth of the type species will be presented 
and commented on, but in addition also those of spe-
cies representing the extremes of natural and/or inter-
specific variation and differences. 
The detailed study of the tooth morphology of thou-
sands of specimens representing all the living genera, 
or some 550 species of Chondrichthyans confirmed 
that teeth are a fundamental systematical tool. 
The dermal denticles and fin spines of the Selachians 
will not be dealt with. Dermal denticles of Selachians 
were the object of an important monography (W. 
Reiff, 1985). 
As for the litigious cases (doubtful validity of genera 
or subgenera, such as e.g. Lepidorhinus, Centrosela-
chus, Rhinotriacis...), the odontological observations 
will be more elaborated on, and the degree in which 
they contribute to validate or invalidate certain 
hypotheses, will be demonstrated. 
Scientific rigour imposes to mention some rare excep-
tions, such as the difficult odontological distinction 
between isolated teeth of a few species of Squatina, 
or of Mustelus. However, at the superspecific level, 
tooth morphology is an infallible key character. 
The objective of this long-term research is to give 
evidence that paleontological determinations based on 
isolated chondrichthyan teeth, which are fairly com-
mon fossils, are not merely possible but are reliable. 
The scientific work of M. LERICHE brilliantly illus-
trated their stratigraphical, paleo-ecological and 
paleo-biogeographical importance. 
C. ARAMBOURG enhanced the importance of such 
studies and E. CASIER developed the study method, 
and the evolutive implications of the root structures. 
Both these eminent successors of LERICHE, as well as 
all the later disciples, have had difficulties in ascertain-
ing the generic assignment of their fossils because of 
their lack of knowledge of the dentition of living species. 
42 J. HERMAN 
The zoological literature giving elaborated anatomical 
and physiological information, or more recently also 
on social behaviour, sensorial abilities and ecological 
details, remains very insignificant as far as the mor-
phology and micro-structure of chondrichthyan teeth 
are concerned. 
Though the general shape of the crown may have 
been superficially described, or illustrated and the 
number of the tooth rows occasionally determined, 
further details of ornamentation and micro-ornamen-
tation of the crown, of morphology, vascularization 
and innervation of the roots, which is fundamental 
information, are never mentioned. This is particularly 
true for the small-sized species, which represent more 
than 90% of this group of fish. 
This series of fascicles will try to fill this gap, offering 
any researcher a commented photographic catalogue 
of the different types of tooth morphology of all the 
living supraspecific taxa of the Chondrichthyans. It 
may enable researchers to detect a link between fossil 
teeth and a living taxon or to be convinced of their 
generic uniqueness, respectively to grasp their affini-
ties and to formulate hypotheses concerning their phy-
logeneses. 
The material required for this investigation was pro-
vided by recent and ancient collections of European 
and American institutions, private collections, expedi-
tions made by the authors along the American, Afri-
can and European coasts, and by donations from 
friends, who are fishermen. 
The North Atlantic deepwater specimens came from 
many fishermen friends in Brittany, especially P. GUE-
GUEN, Lorient, whom I accompanied many times. 
Thanks to them, certain species that had been consi-
dered as very rare were collected relatively frequently. 
The preparation and cleaning of all this material, — 
for which solutions of pancreatine, pepsine, antifor-
mine were very useful —, required benevolent colla-
boration of a lot of friends and other researchers. 
I would like to point out that fundamental help to 
obtain basic material was offered by J.V.L. COM-
PAGNO, and that the practical materialization of this 
study is due to M. STEHMANN. 
The helpfulness of X. MISONNE, director of the I.R. 
S.N.B. - Brussels, enabled me to obtain the numerous 
scanning pictures indispensable to launch this project. 
I would also Hke to express my gratefulness to D. and 
M. HOVESTADT for their permanent intense collabo-
ration and friendship. 
I am also deeply indebted to H. STOUT, Brussels for 
the careful printing of the thousands of photographs 
for this study. 
The figured teeth will be deposited in the following 
institutions: 
— Institut Royal des Sciences Naturelles de Belgique 
(LR.S.N.B.), Bruxelles, Belgium. 
— Natur-Museum und Forschungsinstitut Sencken-
berg (S.M.F.), Frankfurt/M., F.R. of Germany. 


Contributions to the study of the comparative morphology of teeth and other relevant ichthyodorulites in living supraspecific taxa of Chondrichthyan fishes. General introduction

Contributions to the study of the comparative morphology of teeth and other relevant ichthyodorulites in living supraspecific taxa of Chondrichthyan fishes. General introduction

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