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A high diversity in fossil beaked whales (Mammalia, Odontoceti, Ziphiidae) recovered by trawling from the sea floor off South Africa

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Cited By (since 1996):11, Export Date: 4 July 2013, Source: Scopus, Language of Original Document: English, Correspondence Address: Bianucci, G.; Dipartimento di Scienze della Terra, Università di Pisa, via S. Maria, 53, I-56126 Pisa, Italy; email: bianucci@dst.unipi.it, References: ABEL, O., Les odontocètes du Boldérien (Miocène supérieur) des environs d'Anvers (1905) Mémoires du Musée royal d'Histoire naturelle de Belgique, 3, pp. 1-155;
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561
GEODIVERSITAS • 2007 • 29 (4)
© Publications Scientiques du Muséum national d’Histoire naturelle, Paris. www.geodiversitas.com
A high diversity in fossil beaked whales
(Mammalia, Odontoceti, Ziphiidae) recovered by
trawling from the sea oor off South Africa
Giovanni BIANUCCI
Dipartimento di Scienze della Terra, Università di Pisa,
via S. Maria, 53, I-56126 Pisa (Italy)
bianucci@dst.unipi.it
Olivier LAMBERT
Institut royal des Sciences naturelles de Belgique,
Département de Paléontologie, rue Vautier, 29, B-1000 Brussels (Belgium)
olivier.lambert@naturalsciences.be
Klaas POST
Natuurhistorisch Museum Rotterdam, P.O. Box 23452,
NL-3001 Rotterdam (The Netherlands)
klaas@skano.nl
Bianucci G., Lambert O. & Post K. 2007. — A high diversity in fossil beaked whales (Mam-
malia, Odontoceti, Ziphiidae) recovered by trawling from the sea oor off South Africa. Geo-
diversitas 29 (4) : 561-618.
ABSTRACT
Eight new genera and 10 new species of fossil beaked whales (Cetacea, Odon-
toceti, Ziphiidae) are described on the basis of cranial material recovered by
trawling from the sea floor off South Africa. Although no exact stratigraphic
information is known for these fossils, most are strongly phosphoritised (some
even have phosphorite concretions attached), indicating that their fossilization
could be related to one or more of the phosphogenic episodes that occurred in
the South African coastal waters since the latest Oligocene. Considering the
main phosphogenic epochs and the evolutionary level of the majority of the
ziphiids here described, a middle-late Miocene age may be suggested for most,
but not all, of these fossils. e new genera named here more than double the
known diversity of the fossil beaked whales and represent more than one third of
the total diversity of this family (fossil and extant). A parsimony analysis within
the family including the Recent taxa reveals that some of the new fossil taxa
belong to three extant subfamilies redefined here, while the others are outside
these subfamilies; this indicates the presence in the past of some ziphiid line-
ages now extinct. In detail, Microberardius africanus n. gen., n. sp. is placed in
the subfamily Berardiinae together with the Recent Berardius; Izikoziphius rossi
n. gen., n. sp. and
I. angustus n. gen., n. sp. are related to the Recent Ziphius in-
side the subfamily Ziphiinae and Khoikhoicetus agulhasis n. gen., n. sp., Ihlengesi
saldanhae n. gen., n. sp., and Africanacetus ceratopsis n. gen., n. sp. belong to
562
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
the Hyperoodontinae together with the Recent Hyperoodon, Mesoplodon, and
Indopacetus. However, Nenga meganasalis n. gen., n. sp., Pterocetus benguelae
n. gen., n. sp., and Xhosacetus hendeysi n. gen., n. sp., together with the Recent
Tasmacetus, do not fit in any of the three subfamilies mentioned above. Taking
into account the high number of unnamed fragmentary specimens, the fossil taxa
listed above, together with Mesoplodon slangkopi n. sp. and Ziphius sp., probably
represent only a part of the South African fossil ziphiid fauna(s), revealing an
unexpected high diversity for the previously poorly known southern hemisphere
fossil beaked whales. Such a high ziphiid diversity might be locally related to
the upwelling system and resulting high productivity linked to the northward
running cool oceanic Benguela Current entering the shallower waters along the
south-west coast of South Africa and Namibia since the middle Miocene.
SU
Une grande diversité de baleines à bec fossiles (Odontoceti, Ziphiidae) remontées
du fond de la mer au large de l’Afrique du Sud.
Huit nouveaux genres et 10 nouvelles espèces de baleines à bec fossiles (Cetacea,
Odontoceti, Ziphiidae) sont décrits sur base de matériel crânien remonté du
fond de la mer au large de l’Afrique du Sud. Même si aucune information strati-
graphique exacte n’est connue pour l’ensemble de ces fossiles, la plupart sont forte-
ment phosphoritisés (certains montrent même des conctions de phosphorite
attachées), ce qui indique que leur fossilisation/enfouissement pourrait être lié à
l’un ou l’autre des épisodes de phosphogenèse se produisant dans les eaux tières
d’Afrique du Sud depuis l’Oligocène terminal. Considérant les principales épo-
ques de phosphogenèse et le degré d’évolution des ziphiidés décrits ici, un âge
Miocène moyen à supérieur peut être propopour la plupart de ces fossiles. Les
nouveaux genres décrits doublent la diversité connue des baleines à bec fossiles
et représentent plus du tiers de la diversité totale de la famille. Une analyse de
parcimonie au sein de la famille incluant les taxons actuels révèle qu’une partie des
nouveaux taxons fossiles appartiennent aux trois sous-familles actuelles redéfinies
ici alors que les autres taxons restent en dehors de ces sous-familles, ce qui indique
la présence dans le passé de lignées de ziphiidés maintenant éteintes. En détail,
Microberardius africanus n. gen., n. sp. se place dans la sous-famille Berardiinae
avec le genre actuel Berardius ; Izikoziphius rossi n. gen., n. sp. et I. angustus n. gen.,
n. sp. sont regroupés avec le genre actuel Ziphius dans la sous-famille Ziphiinae
et Khoikhoicetus agulhasis n. gen., n. sp., Ihlengesi saldanhae n. gen., n. sp., et
Africanacetus ceratopsis n. gen., n. sp. appartiennent à la sous-famille Hyperoodon-
tinae avec les genres actuels Hyperoodon, Mesoplodon, et Indopacetus. Cependant,
Nenga meganasalis n. gen., n. sp., Pterocetus benguelae n. gen., n. sp., Xhosacetus
hendeysi n. gen., n. sp. et le genre actuel Tasmacetus ne rentrent dans aucune des
sous-familles mentionnées ci-dessus. En tenant compte du grand nombre de spéci-
mens trop fragmentaires pour être nommés, la liste de taxons fossiles ci-dessus ne
représente probablement avec Mesoplodon slangkopi n. sp. et Ziphius sp. qu’une
partie de la ou des faune(s) de ziphiidés fossiles d’Afrique du Sud, ce qui révèle une
diversité étonnament élevée pour les baleines à bec de l’hémisphère sud, jusqu’ici
très mal connues. Une telle diversité de ziphiidés pourrait se corréler localement
avec le système d’upwelling et la haute productivité résultante liés à la remontée
du courant océanique froid Benguela dans les eaux moins profondes de la côte
sud-ouest d’Afrique du Sud et de Namibie depuis le Miocène moyen.
MOTS CLÉS
Mammalia,
Cetacea,
Odontoceti,
Ziphiidae,
baleines à bec,
Berardiinae,
Hyperoodontinae,
Ziphiinae,
fossile,
Néogène,
Miocène,
Afrique du Sud,
phylogénie,
phosphorites.
KEY WORDS
Mammalia,
Cetacea,
Odontoceti,
Ziphiidae,
beaked whales,
Berardiinae,
Hyperoodontinae,
Ziphiinae,
fossil,
Neogene,
Miocene,
South Africa,
phylogeny,
phosphorites.
563
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
South Africa
200
m
30°S
35°
15° 20° 25°E
1000
m
St. Helena Bay
Saldanha Bay
Cape Columbine
Cape Town
Cape Point
Cap
e Agulha
s
Agulhas Bank
Slangkop
Port Elizabeth
Benguela Curr
en
t
Africa
Fishing vessels
Research vessels
Fig. 1. — Map of South African coast showing mainland localities near which fossil ziphiid skulls have been recovered by trawling.
Marine locations of precisely recorded (with geographic coordinates) sites where ziphiid skulls were recovered by shing and research
vessels are also indicated.
INTRODUCTION
e fossil history of the beaked whales (Ziphiidae)
is poorly known. Although the sheer amount of
described fossil species might seem impressive, the
lack of fossils from large areas of the world (especially
the entire southern hemisphere) and long geological
periods (late Pliocene to early Holocene) prevents
a comprehensive view.
From the northern hemisphere currently eight
Miocene to Pliocene fossil genera are recognised
on the basis of cranium material, with 12 species
described. e North Sea area (mainly from Bel-
gium) yielded most descriptions with members of
the genera Aporotus du Bus, 1868, Archaeoziphius
Lambert & Louwye, 2006, Beneziphius Lambert,
2005, Caviziphius Bianucci & Post, 2005, Chone-
ziphius Duvernoy, 1851, and Ziphirostrum du
Bus, 1868. From the Mediterranean (all from
Italy) Messapicetus longirostris Bianucci, Landini &
Varola, 1992 and Tusciziphius crispus Bianucci,
1997 were reported. Choneziphius macrops (Leidy,
1876) was first described from the east coast of the
USA and Messapicetus longirostris and Tusciziphius
crispus have been recognised there (Whitmore et
al. 1986; Fuller & Godfrey 2007; Post pers. obs.).
e Pacific coast of the USA yielded Squaloziphius
emlongi Muizon, 1991 from the early Miocene of
Washington State (in its original description this
species was considered as the oldest known ziphiid,
but scholars still debate whether or not this species
should be considered a basal ziphiid or belonging to
a separate family [Fordyce & Barnes 1994; Lambert
2005]). Lastly, a series of undetermined ziphiids
including a possible fossil member of the genus
Berardius (Takahashi et al. 1989) and an unnamed
ziphiine (Horikawa et al. 1987) are mentioned from
the Pacific coast of Japan.
Contrary to the multitude of fossil species from
the northern hemisphere, only one fossil species
has been described from the southern hemisphere:
Ninoziphius platyrostris Muizon, 1983 from the
564
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
early Pliocene of Peru. A few more ziphiid fos-
sils have been mentioned in the literature (e.g.,
Glaessner 1947; Mead 1975), but none of these
fossils showed diagnostic characters enabling a
more precise identification.
All the above-mentioned fossil members of the
ziphiid family come from Miocene to early Pliocene
strata and, to date, only a few fragmentary ziphiid
remains have been recovered from younger strata
(Oishi & Hasegawa 1994; Cozzuol 1996). Given
the extant record of the family at least 21 known
species in six genera (Dalebout
et al. 2002) more
fossils from Pliocene and Pleistocene strata are to
be expected.
e purpose of this work is to describe several
fossil ziphiid skulls recovered by trawling from the
Neogene strata outcropping on the sea floor off the
South African coasts (Fig. 1). Ten new species of
ziphiids belonging to nine genera (of which eight
are new to science) are reported. ese taxa greatly
increase our knowledge of the fossil ziphiids and
reveal the high diversity of Mio-Pliocene ziphiids
from the southern hemisphere. ese preliminary
results also yield new insights concerning the phy-
logeny of the family.
Most fossils examined here are strongly phos-
phatised and have phosphorite concretions attached.
e worldwide phenomenon of phosphatised,
glauconised, and/or cemented fossil ziphiid remains
dredged from sea floor is often mentioned in the
literature. Isolated fossil rostra occur remarkably
abundantly within middle-late Miocene and/or
early Pliocene marine transgression gravels, together
with phosphorite nodules, bones from other marine
mammals, and shark teeth. Such fossils are trawled
from the sea floor near the ornton Bank in the
North Sea off the Netherlands and in the North
Atlantic off the Canary Islands (Post pers. obs.);
from the Miami Terrace in the Northern Strait
of Florida, the Blake Plateau off the east coast of
Florida, off San Clemente Island California, the
Clarion-Clipperton Fracture zone in the Pacific,
and othe Peruvian coast in the South Pacific
(Whitmore et al. 1986); about 1200 km south of
Tasmania in the South Pacific Ocean (Fordyce &
Cullen 1979); and off Sado Island in the sea off
Japan (Horikawa et al. 1987; Tazaki et al. 1987).
e striking abundance of these fossils in South
African waters and many seas worldwide, combined
with their petrologic appearance and the fact that
these faunas are characterised by unusually high
and dominant ziphiid diversity illustrates the need
of further study of this interesting and worldwide
phenomenon.
A
bbreviAtions
IGF Museo di Geologia e Paleontologia, Università
di Firenze;
IRSNB Institut royal des Sciences naturelles de
Belgique, Brussels;
MNHN Muséum national d’Histoire naturelle, Paris;
MSNTUP Museo di Storia Naturale e del Territorio,
Università di Pisa;
MZUF Museo di Zoologia, Universi di Firenze;
NMR Natuurhistorisch Museum Rotterdam;
NNML Nationaal Natuurhistorisch Museum Natu-
ralis, Leiden;
PEM Port Elizabeth Museum, Port Elizabeth,
South Africa;
SAM Iziko South African Museum, Cape Town;
USNM United States National Museum, Smithsonian
Institution, Washington D.C.;
ZMA Zoölogisch Museum Amsterdam.
MATERIAL AND METHODS
s
pecimens
Although some fragmentary rostra were already
listed and referred to extant genera Mesoplodon
and Ziphius by Haughton (1956), all fossil ziphi-
ids examined in this article are described for the
first time. e fossils are kept in SAM except the
holotypes of Izikoziphius rossi n. gen., n. sp. and
Africanacetus ceratopsis n. gen., n. sp. kept respec-
tively in PEM and in NMR.
During this study and from previous works on
fossil ziphiids (Bianucci 1997; Lambert 2005), we
realized that the regularly found isolated rostra
of fossil beaked whales are poorly diagnostic. For
example, the Mesoplodon-like heavy rostra with a
mesorostral groove filled by the vomer are generally
referred to several fossil species of the Recent genus
Mesoplodon (e.g., Owen 1870; Capellini 1885) but
morphological characters or arguments have never
been presented. ese nominal species have some-
times been grouped into Cuvier’s species Mesoplo-
565
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
don longirostris (Abel 1905; Bianucci 1997). Mead
(1975) and Bianucci (1997) already predicted that
similar rostral morphologies with strong mesorostral
ossification, today mostly observed in the genus
Mesoplodon, might be present in some unknown
fossil genera of this family. e well preserved and
diversified material from South Africa confirms this
hypothesis. In fact, among these fossils there are
clearly some well preserved skulls with a peculiar
vertex unlike all other known beaked whales, but
with a Mesoplodon-like rostrum. So in this study
for the description of new taxa and for comparison
we decided to use only those specimens including
at least the more diagnostic dorsal surface of the
cranium with the vertex.
e South Africa fossil ziphiids described here are
compared with most significant described taxa of
fossil beaked whales, all directly examined by us, and
with the skulls of most Recent ziphiid species, mostly
available in the SAM collection (see Appendix 1).
s
ystemAtics
e systematic classification used in the following
section anticipates the results of our phylogenetic
analysis (see below), where the three subfamilies of
the Ziphiidae (Berardiinae, Hyperoodontinae, and
Ziphiinae) are redefined. Some new genera here
described do not fit in these subfamilies and are
considered as Ziphiidae incertae sedis.
SYSTEMATICS
Order CETACEA Brisson, 1762
Suborder ODONTOCETI Flower, 1867
Family ZiphiidAe Gray, 1850
Subfamily berArdiinAe Moore, 1968
type genus. — Berardius Duvernoy, 1851.
o
ther
generA
included
. — Archaeoziphius Lambert &
Louwye, 2006 and Microberardius n. gen.
emended diAgnosis. — Berardiinae differ from all other
Ziphiidae in the presence of a nodular protuberance
formed by the interparietal or the frontals on the vertex
Berardius spp. are further characterized by two pairs of
apical and subapical enlarged teeth on the mandible; this
character still needs to be confirmed in Archaeoziphius
and Microberardius n. gen.
Other characters differentiating Berardiinae from more
derived taxa are mostly symplesiomorphies: narrow and
thin premaxillary crest on the low vertex; supraoccipital
lower than the frontals on the vertex.
discussion
e content of the subfamily Berardiinae as defined
here is more similar to the subtribe Berardiina of
Moore (1968) (only including Berardius) than to
the tribe Berardiini of Muizon (1991) (including
Berardius, Ninoziphius, and Tasmacetus) or to
the subfamily ?Berardiinae of Lambert (2005)
(including Berardius and Tasmacetus). Additional
specimens of Ninoziphius with a well preserved
vertex could clarify the relationships of this ge-
nus in the proposed framework. A fragmentary
cranium from the Neogene of Japan is referred
to Berardius sp. (Takahashi et al. 1989); despite
general shape similarities with Berardius, the vertex
might be too incomplete to provide diagnostic
characters.
e presence of an ossified mesethmoid filling
a significant portion of the mesorostral groove,
observed in Berardius, but not verifiable in Micro-
berardius n. gen., is also noted in SAM PQ 69676
(see below, Nenga n. gen.).
Genus Microberardius n. gen.
t
ype
species
. — Microberardius africanus n. gen., n. sp.,
by present designation.
e
tymology
.From the Ancient Greek mikros”, small
and Berardius, a Recent ziphiid genus. Microberardius
n. gen. for the small size of the species and its cranial
similarities with Berardius spp. Gender masculine.
d
iAgnosis. — Same as for the species.
Microberardius africanus n. sp.
holotype. — SAM PQ 3003, a partial skull including
the anteriorly worn rostrum, most of the dorsal surface
of the cranium and the nearly complete vertex.
e
tymology
.africanus” for the African origin of
the holotype.
566
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
mesethmoid
antorbital notch
maxillary foramen
maxillary crest
maxillary crest
premaxillary crest
premaxillary crest
premaxillary foramen
premaxillary sac fossa
premaxillary sac fossa
vomer
vomer
vomer
vomer
vomer
maxilla
maxilla
maxilla
maxilla
maxilla
premaxilla
premaxilla
deep lateral sulci on the vomer
mesorostral groove
frontal
nasals
nasal
interparietal
interparietal
frontals
frontal
frontal
frontal
bony nares
dorsal infraorbital
foramen
dorsal infraorbital foramen
infraorbital foramen
lacrimal
mark of maxilla-palatine suture
mark of maxilla-palatine suture
worn sulci for major palatine foramina
worn sulci for major palatine foramina
worn lateral margin
phosphorite concretion
antorbital notch
lacrimal
cerebral cavity
choana
A
B
C
n. gen., n. sp.
Fig. 2. — Skull of Microberardius africanus n. gen., n. sp. (SAM PQ 3003, holotype): A, dorsal view; B, lateral view; C, ventral view.
Scale bar: 10 cm.
567
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
premaxillary
crest
premaxillary crest
premaxilla
lacrimal
maxillary crest
maxillary foramen
ascending process
of premaxilla
premaxillary
crest
maxilla
maxilla
maxilla
maxilla
premaxilla
nasal
nasal
nasals
vomer
interparietal
frontals
frontal
bony nares
mesethmoid
mesethmoid
A B
C
D
Fig. 3. — Skull of Microberardius africanus n. gen., n. sp. (SAM PQ 3003, holotype): A, detail of the vertex in dorsal view; B, corre-
sponding line drawing; C, anterior view; D, corresponding line drawing. Scale bars: A, B, 5 cm; C, D, 10 cm.
t
ype
locAlity
. — No data. Trawled off the South
African coast.
d
iAgnosis. — Microberardius africanus n. gen., n. sp.
differs from Berardius in: smaller size; thickening of the
vomer in the anterior portion of the mesorostral groove;
rostrum higher than wide along most of its length; nar-
rower rostrum base and maxillary crest not extended
on the rostrum base. It differs from Archaeoziphius in:
slightly concave premaxillary sac fossa; higher maxillary
crest; more anteriorly pointed nasals; larger distance
between the maxillae across the vertex and the nodular
bone in the posterior vertex being the interparietal in-
stead of the frontals.
description (Figs 2; 3; tAble 1)
Considering the height of the preserved apex of the
rostrum, a significant part of the anterior portion
is probably missing. Where preserved, the rostrum
height is larger than the width at the same level,
except along the base. e dense vomer lls the
anterior part of the mesorostral groove, leaving a
widely open space posteriorly for the presumed
anterior extension of the ossified mesethmoid.
Among Recent ziphiids, a lengthened ossied
portion of the mesethmoid is only observed in
Berardius spp. (e.g., B. arnuxii, SAM ZM 39296;
B. bairdii in True 1910: pl. 26). A marked sulcus
laterally separates the thickened vomer from the
premaxilla.
e premaxillary sac fossa is slightly concave. e
ascending process of the premaxilla lacks a constric-
tion under the premaxillary crest in anterior view.
e moderate elevation towards the vertex does not
reach vertical. e premaxillary crest is transversely
oriented without a distinct dorsal thickening or
568
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
premaxilla
maxilla
maxilla
maxilla
premaxilla
nasal
nasal
nasals
supraoccipital
supraoccipital supraoccipital
interparietal
interparietal
interparietal
frontal
frontal
frontal
A
B C
Fig. 4. — Vertex of skull of Berardius arnuxii (SAM ZM 39296): A, dorsal view; B, posterior view; C, lateral view. Note the nodular inter-
parietal between the frontals and the supraoccipital that does not reach the vertex dorsally. Scale bar: 10 cm.
widening, similar to Archaeoziphius and Berardius.
e right crest is somewhat wider than the left. e
large maxillary foramen just posterior to the level
of the antorbital notch is anteriorly followed by a
wide and short groove. Both right premaxillary and
maxillary foramina are located more posteriorly than
their left side counterparts. A high maxillary crest
culminating on the preorbital process adjoins the
maxillary foramen laterally. Unlike in Berardius, the
crest does not extent onto the rostrum base.
e dorsal surface of the nasals is damaged.
eir outline is pentagon-shaped, their anterior
point reaches the level of the premaxillary crest
and the anterolateral corner does not thrust into
the premaxillary crest. e anteromedian groove
between the nasals seen in dorsal view is probably
caused by erosion. e naso-frontal suture is ir-
regular with a posteriorly longer right nasal. e
frontals are more transversely compressed and
lower than the nasals on the vertex. Posterior to
the frontals, lower and slightly shifted to the right,
is a nodular uneven bone interpreted as an inter-
parietal. Its low position relative to the vertex in
lateral view suggests that the supraoccipital did
not reach the vertex dorsally. Such a bone is at
least occasionally observed in a similar position in
Berardius arnuxii (e.g., SAM ZM 39296, Fig. 4;
Moore 1968: figs 19, 23). In other specimens of
Berardius spp. and in Archaeoziphius, the frontals
themselves form a nodular eminence between the
lower supraoccipital and the nasals.
Berardiinae indet.
reFerred specimen. — SAM PQ 2198, a partial skull
including the rostrum base, the premaxillary sac fossae,
and the vertex.
l
ocAlity
. — No data. Trawled off the South African
coast.
description And discussion (Fig. 5; tAble 1)
is specimen shows a severely worn rostrum and
a damaged vertex with poorly preserved premaxil-
lary crests. e rostrum base is similar to that of
Nenga n. gen. (see below). However, differences
within the cranium prevent an attribution to the
latter genus: the premaxillary sac fossa is much
longer (quantified as the distance between the
anterior margin of the bony nares and the pre-
maxillary foramen); the elevation of the premaxilla
towards the lower vertex is more progressive and
the nasals are longer and transversely narrower.
Posterior to the nasals, the sutures between the
transversely compressed frontals and a median
rounded bone could be distinguished. As in Berar-
dius arnuxii and Microberardius n. gen., this bone
is interpreted as the interparietal. is character
569
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
mesethmoid
maxillary crest
maxillary crest
marks of maxilla-frontal suture
premaxillary crest
premaxillary crest
premaxillary
crest
premaxillary
crest
maxillary foramen
premaxillary foramen
premaxillary sac fossa
premaxillary sac fossa
vomer
vomer
vomer
maxilla
maxilla-palatine suture?
maxilla
maxilla
maxilla
maxilla
maxilla
worn anterior portion
of the rostrum
worn anterior portion
of the rostrum
ascending
process of
premaxilla
premaxilla
premaxilla
nasals
nasal
nasal
nasal
interparietal?
interparietal?
frontals
frontals
frontal
bony nares
bony nares
A
B
D E
C
Fig. 5. — Skull of Berardiinae indet. (SAM PQ 2198): A, dorsal view; B, anterior view; C, lateral view; D, detail of the vertex in dorsal
view; E, corresponding line drawing. Scale bars: A-C, 10 cm; D, E, 5 cm.
570
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
is our main reason to include SAM PQ 2198 in
the subfamily Berardiinae.
Subfamily ZiphiinAe Gray, 1850
type genus. — Ziphius Cuvier, 1823.
o
ther
generA
included
. — Aporotus, Beneziphius,
Caviziphius, Choneziphius, Messapicetus, Tusciziphius,
Ziphirostrum and Izikoziphius n. gen.
e
mended
diAgnosis
. — e subfamily Ziphiinae differs
from all other Ziphiidae in having the contact between
nasal and premaxillary crest reduced and the transverse
premaxillary crest directed anterolaterally. It further
differs from the Berardiinae in the lack of a nodular
interparietal on the vertex, from the Hyperoodontinae,
Khoikhoicetus n. gen., Pterocetus n. gen., Xhosacetus n. gen.
(three new genera described below), and Tasmacetus in
the lack of an intrusion of the nasal into the narrow
premaxillary crest.
Genus Izikoziphius n. gen.
t
ype
species
. — Izikoziphius rossi n. gen., n. sp., by
present designation.
other species included.Izikoziphius angustus
n. gen., n. sp.
e
tymology. — Iziko is the network of South African
museums, which includes the South African Museum
where most of the specimens studied here are stored,
Ziphius is a Recent ziphiid genus. Gender masculine.
d
iAgnosis. — Izikoziphius n. gen. differs from all the
other members of the Ziphiinae in the presence of a
fossa on the anterior surface of the ascending process
of the premaxilla distinct from the premaxillary sac
fossa. It differs from Ziphius in: longer rostrum; lack of
a prenarial basin; lesser asymmetry of the premaxillary
sac fossae (< 0.40) and longer contact between nasal
and premaxillary crest. It differs from Tusciziphius in:
the barely concave premaxillary sac fossa and the ante-
rior part of the nasal not contacting the premaxillary
crest. It differs from Choneziphius in: longer rostrum;
premaxillae medially separated on the rostrum by the
thickened vomer and barely concave premaxillary sac
fossa. It differs from Caviziphius in: premaxillae medial-
ly separated on the rostrum by the thickened vomer;
lower rostrum base and less asymmetric and barely
concave premaxillary sac fossa. It differs from Aporotus,
Beneziphius, Messapicetus, and Ziphirostrum in: longitu-
dinally elongated nasals; premaxillae medially separated
on the rostrum by the thickened vomer and lack of a
constriction of the ascending process of the premaxilla
(last character less clearly present in Messapicetus). Both
species of Izikoziphius n. gen. have a somewhat smaller
cranium size than Ziphius cavirostris.
Izikoziphius rossi n. sp.
holotype. — PEM N 3265, a partial skull including
the rostrum, the anterior part of the cranium, and the
vertex.
r
eFerred specimen. — SAM PQ 2086, a partial skull
including the rostrum, the anterior part of the cranium,
and the vertex, trawled off the South African coast
e
tymology. — Honouring Dr. Graham J. B. Ross, a
cetologist formerly at the PEM who studied in detail
extant cetaceans, including the ziphiids, of South Af-
rican waters.
t
ype
locAlity
. — No data. Trawled off the South
African coast.
d
iAgnosis
. — Izikoziphius rossi n. gen., n. sp. differs
from I. angustus n. gen., n. sp. in: rostrum wider than
high at mid-length; wide rostrum base; maxillary crest
extending on the rostrum base; wide fossa on the anterior
surface of the ascending process of the right premaxilla
excavating the nasal; anteromedian depression of the
dorsal surface of the nasals and a distinctly more elevated
right side of the vertex.
description (Figs 6-9; tAble 2)
e rostrum is wider than high at mid-length. e
rostrum base is particularly wide (more prominent
in the holotype); the lateral margin of the subhori-
zontal platform of the maxilla present from mid-
way along the rostrum progressively diverges and
rises to a crest towards the antorbital notch. e
highest dome-like portion of the crest is located
on the preorbital process. Medially to this dome,
the large maxillary foramen opens anterolaterally
with a circular section.
e premaxilla is longer anteriorly than the max-
illa. e alveolar groove is either absent or much
reduced.
e mesorostral groove is filled with the thickened
vomer, but a wide median groove is retained poste-
riorly. e maximum elevation of the vomer is around
two thirds of the length of the rostrum in SAM PQ
2086, less pronounced in PEM N 3265.
571
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
antorbital notch
maxillary foramen
maxillary crest
maxillary crests
premaxillary crest
premaxillary crest
premaxillary
foramen
premaxillary sac fossa
vomer
vomer
maxilla
maxilla
maxilla
maxilla
premaxilla
premaxilla
premaxilla
premaxilla
nasals
nasals
frontals
bony nares
vomer
vomer
maxilla
infraorbital foramen
marks of maxilla-palatine suture
antorbital notch
choana
A
B
C
Fig. 6. — Skull of Izikoziphius rossi n. gen., n. sp. (PEM N 3265, holotype): A, dorsal view; B, lateral view; C, ventral view. Scale bar: 10 cm.
e narrow premaxillary foramen, posterior to
the antorbital notch, is depressed compared to the
slightly concave premaxillary sac fossa. e elevated
lateral margin of the fossa overhangs the maxilla
along its posterior half. e lateral margins of the
ascending processes of the premaxillae are parallel
until the elevated vertex. e vertical anterior sur-
face of each ascending process is hollowed out by
572
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
premaxillary
crest
premaxillary crest
premaxillary crest
fossa on
premaxilla
and nasal
fossa related
to terminal
foramen
premaxillary
crest
maxilla
maxilla
maxilla
premaxillapremaxilla
premaxilla
nasal
nasal
nasals
frontals
bony nares
bony nares
mesethmoid
ascending process
of premaxilla
A B
D
C
Fig. 7. — Vertex of skull of Izikoziphius rossi n. gen., n. sp. (PEM N 3265, holotype): A, dorsal view; B, corresponding line drawing;
C, anterior view; D, corresponding line drawing. Scale bars: A, B, 5 cm; C, D, 10 cm.
a deep elliptical fossa, extending medially on the
anterolateral surface of the nasal. e right fossa is
wider than the left. In relation to the morphology of
the air sacs connected to the nasal passages and the
surrounding bony configuration in Recent ziphiids
and other odontocetes (Heyning 1989; Cranford et
al. 1996), this fossa corresponds to the location of
the posterior nasal sac (sensu Heyning 1989, more
generally the caudal sac in Cranford et al. 1996).
We suggest that in Izikoziphius n. gen. a homo-
logous air sac was located in this elliptical fossa.
A pair of smaller fossae is present ventromedially
at the naso-mesethmoid suture (best seen in SAM
PQ 2086), probably related to the foramina of the
terminal nerve. e mesethmoid is weakly or not
keeled under the nasals.
e relatively thin premaxillary crests are antero-
laterally directed. e right crest is twice longer than
the left (best preserved in PEM N 3265).
e large nasals, widest at mid-length and slightly
longer than wide, are anteriorly longer than the
premaxillary crests. eir dorsal surface is slightly
anteromedially depressed. e naso-frontal suture
is posteriorly irregularly convex with the right nasal
longer than the left. e frontals were originally
probably short.
In anterior view, the right side of the vertex is
considerably higher than the left side.
573
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
mesethmoid
antorbital notch
maxillary foramen
premaxillary foramen
premaxillary
crest
maxillary crest
maxillary crest
premaxilla
premaxilla
premaxilla
premaxillary sac fossa
vomer
vomer
vomer
maxilla
maxilla
maxilla
marks of maxilla-palatine suture
marks of maxilla-palatine suture
premaxilla
premaxilla
premaxilla
nasals
nasals
frontals
bony nares
vomer
vomer
maxilla
infraorbital foramen
major palatine
foramina
choana
A
B
C
D
Fig. 8. — Skull of Izikoziphius rossi n. gen., n. sp. (SAM PQ 2086): A, dorsal view; B, anterior view; C, lateral view; D, ventral view.
Scale bar: 10 cm.
Izikoziphius angustus n. sp.
holotype. — SAM PQ 3004, a partial skull including
the rostrum and most of the dorsal surface of the cra-
nium with the vertex.
etymology. — From Latin angustus”, narrow, for the
transversely compressed rostrum, narrower than in the
type species I. rossi n. gen., n. sp.
type locAlity. Trawled at 34°39’82S, 18°0331E, south-
west of Cape Town, Atlantic Ocean, depth of 450 m.
d
iAgnosis
. — Izikoziphius angustus n. gen., n. sp. differs
from I. rossi n. gen., n. sp. in: longer rostrum higher than
wide; narrower rostrum base; more elevated maxillary
574
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
premaxillary
crest
premaxillary
crest
premaxillary crest
fossa on
premaxilla
and nasal
fossa related
to terminal
foramen
premaxillary
crest
maxilla
maxilla
maxilla
premaxilla
premaxilla
nasal
nasal
nasals
frontals
bony nares
mesethmoid
mesethmoid
ascending
process of
premaxilla
A B
D
C
Fig. 9. — Vertex of skull of Izikoziphius rossi n. gen., n. sp. (SAM PQ 2086): A, dorsal view; B, corresponding line drawing; C, anterior
view; D, corresponding line drawing. Scale bars: 5 cm.
crest, not extending on to the rostrum; mesethmoid
distinctly keeled under the nasals; nasals much longer
than wide and right side of vertex less elevated.
description (Figs 10; 11; tAble 2)
e only known specimen is a well preserved skull
including the complete rostrum, most of the dorsal
surface of the cranium, and the vertex.
e moderately elongated rostrum is higher
than wide at mid-length and the dorsal surface
of the maxilla is narrow. e rostrum base is nar-
rower than in Izikoziphius rossi n. gen., n. sp.; the
widening toward the antorbital notch is abrupt.
e thickened vomer completely fills the meso-
rostral groove and is slightly higher than the
premaxilla for its entire length. Only the apical
premaxillary portion of the rostrum shows a
concave dorsal surface. No alveolar groove could
be detected.
e premaxillary foramen is posterior to the
antorbital notch, roughly in line with the large,
but transversely compressed, maxillary foramen.
e slightly concave premaxillary sac fossa, as in
Izikoziphius rossi n. gen., n. sp., overhangs the
maxilla along its posterior part. e vertical ante-
rior surface of the ascending process of the right
premaxilla is excavated by a fossa less developed
medially than in Izikoziphius rossi n. gen., n. sp.,
only contacting the nasal for a short distance.
e left premaxilla is too damaged to determine
575
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
mesethmoid
antorbital notch
maxillary foramen
maxillary crest
maxillary crest
premaxillary
crest
premaxillary foramen
premaxillary sac fossa
vomer
maxilla
maxilla
premaxilla
nasals
frontals
bony nares
dorsal infraorbital
foramen
vomer
vomer
vomer
maxilla
maxilla
maxilla
premaxilla
premaxilla
nasal
marks of maxilla-palatine suture
marks of maxilla-palatine suture
palatine foramina
marks of maxilla-jugal suture
maxilla
frontal
infraorbital foramen
marks of maxilla-jugal suture
antorbital notch
lacrimal
choana
A
B
C
Fig. 10. — Skull of Izikoziphius angustus n. gen., n. sp. (SAM PQ 3004, holotype): A, dorsal view; B, lateral view; C, ventral view. Scale
bar: 10 cm.
576
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
premaxillary
crest
premaxillary
crest
vertical
foramina
infraorbital
foramen
lacrimal
maxilla
maxilla
maxilla
premaxilla
nasal
nasal
nasals
frontals
frontal
bony nares
mesethmoid
mesethmoid
A B
C
D
maxillary
foramen
maxillary crest
premaxillary
sac fossa
fossa on
premaxilla
premaxillary crest
vomer
ascending
process of
premaxilla
premaxilla
maxilla
Fig. 11. — Skull of Izikoziphius angustus n. gen., n. sp. (SAM PQ 3004, holotype): A, detail of the vertex in dorsal view; B, correspon-
ding line drawing; C, anterior view; D, corresponding line drawing. Scale bars: A, B, 5 cm; C, D, 10 cm.
the presence of a fossa. e keeled mesethmoid
nearly completely covers the anterior surface of
the nasals.
At the level of the preorbital process, the dome-
like maxillary crest is more elevated than in Iziko-
ziphius rossi n. gen., n. sp. and does not extend into
the rostrum base.
On the elevated vertex the premaxillary crests
are anterolaterally directed, similar to Izikoziphius
rossi n. gen., n. sp. e nasals are longer compared
to their width than in the latter species and their
dorsal surface is flat.
Genus Ziphius Cuvier, 1823
t
ype
And
only
species
. — Ziphius cavirostris Cuvier,
1823, by monotypy.
Ziphius sp.
reFerred specimen. SAM PQ 2826, a fragment of
cranium including most of the vertex, the right and part
of the left premaxillary sac fossae.
l
ocAlity. — Trawled at 35°11’S, 23°26’E, south coast
of South Africa, Indian Ocean, depth of 1000 m.
577
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
right premaxillary
crest
right premaxillary
crest
left premaxillary
crest
left
premaxillary
crest
right premaxillary
sac fossa
premaxillary
sac fossa
nasals
nasals
mesethmoid
ascending
process
of premaxilla
A B
C D
E
Fig. 12. — Skull fragment of Ziphius sp. (SAM PQ 2826): A, dorsal view; B, corresponding line drawing; C, lateral view; D, anterior
view; E, corresponding line drawing. Scale bars: A, B, 5 cm; C-E, 10 cm.
description And discussion
(F
ig. 12; tAble 3)
e anterior surface of the ascending process
of the premaxilla is distinctly concave up to its
dorsal portion, overhanging the premaxillary sac
fossa. e highly asymmetric premaxillary crests
(the right crest two times wider than the left) are
anterolaterally directed. e nasals are greatly
elongated anteriorly, being almost twice longer
than wide. eir median suture is anteriorly shifted
to the left.
SAM PQ 2826 only differs from the Recent
Ziphius cavirostris in: its larger size (see comparison
of measurements with the largest skull of Z. cavi-
rostris from the SAM collection, Table 3), the longer
contact between nasal and premaxillary crest (a
condition intermediary between Z. cavirostris and
the Pliocene Tusciziphius crispus), and the relatively
smaller nasals.
Considering the strong similarities with Z. cavi-
rostris at the level of the vertex, this specimen
should be referred to the same genus. Because
of its clearly larger size it may represent a new
species of Ziphius, but in view of its fragmentary
preservation diagnosis at specific level is not cur-
rently possible.
578
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
Subfamily hyperoodontinAe Gray, 1866
type genus. — Hyperoodon Lacépède, 1804.
o
ther
generA
included
. — Indopacetus Moore, 1968,
Mesoplodon Gervais, 1850, Ihlengesi n. gen., Africanacetus
n. gen., and Khoikhoicetus n. gen.
e
mended diAgnosis. — Hyperoodontinae differ from
all the other Ziphiidae in the deep anteromedian excava-
tion of the nasals.
discussion
Hyperoodontinae as defined here follows the content
of the subfamily suggested by Muizon (1991); they
correspond neither to the tribe Hyperoodontini sensu
Moore 1968, including Hyperoodon, Indopacetus,
Mesoplodon, and Tasmacetus nor to the subtribe
Hyperoodontina sensu Moore 1968, only including
Hyperoodon and Mesoplodon.
Genus Khoikhoicetus n. gen.
type species. — Khoikhoicetus agulhasis n. gen., n. sp.,
by present designation.
e
tymology
. — Khoikhoi is one of the ethnic groups oc-
cupying south-western Africa, closely related to the Bush-
men, “cetus” from Latin, whale. Gender masculine.
d
iAgnosis. — Same as for the species.
Khoikhoicetus agulhasis n. sp.
holotype. — SAM PQ 2678, partial skull including
most of the rostrum, the anterior part of the cranium,
and the vertex.
e
tymology. — e holotype was found offshore from
Cape Agulhas, a locality on the south coast of South Africa.
e oceanic current running along the south-east coast
of South Africa is also named Agulhas Current.
type locAlity. — No exact locality. Trawled west of Cape
Agulhas, south coast of South Africa, Indian Ocean.
d
iAgnosis
. — Khoikhoicetus agulhasis n. gen., n. sp.
differs from all the other Hyperoodontinae in lacking
the posterolaterally directed premaxillary crest. It differs
from Indopacetus in: smaller size; narrow rostrum base;
narrower premaxillary crests and nasals longer than
the frontals on the vertex. It differs from Africanacetus
n. gen., Hyperoodon, Ihlengesi n. gen., and Mesoplodon in:
shorter intrusion of the nasal in the premaxillary crest;
premaxillary crest not overhanging the premaxillary sac
fossa. e space between the premaxillary crests is wider
than in Hyperoodon and Mesoplodon.
description (Figs 13; 14; tAble 4)
On the only known skull, the rostrum was probably
relatively short, not much longer than the preserved
length. It is somewhat wider than high along its ante-
rior half and as wide as high posteriorly. e meso-
rostral groove is filled by the vomer, with a median
suture on the posterior half. e ventral margin of
the alveolar groove, lacking marks of alveoli, extends
to the antorbital notch; contrary to Mesoplodon grayi,
M. hectori, M. layardii, and M. slangkopi n. sp. (see
below) this feature is not visible in dorsal view.
e rostrum base lacks a prominental notch; the
antorbital notch is wide and probably shallow, at the
level of the premaxillary foramen and slightly anterior
to the small maxillary foramen lying along the premaxil-
la-maxilla suture. Posterior to the antorbital notch,
a low maxillary crest thickens the preorbital process,
with a lateral slope similar to Africanacetus n. gen.
e weakly asymmetric premaxillary sac fossae
are anteromedially tilted. e ascending process is
moderately constricted in anterior view. e fora-
mina for the terminal nerve in the mesethmoid
are strongly asymmetric; the left foramen is much
smaller than the right.
e premaxillary crest is thin and laterally elon-
gated, with a vertical anterior surface. e poste-
rior projection of the premaxilla along the nasal
reaches the frontal. e anterolateral corner of the
roughly pentagon-shaped nasals forms only a small
part of the premaxillary crest; the dorsal surface is
anteromedially depressed. e naso-frontal suture
is anteriorly pointed; the left nasal extends longer
posteriorly than the right nasal.
Genus Ihlengesi n. gen.
type species. — Ihlengesi saldanhae n. gen., n. sp., by
present designation.
e
tymology
. — Ihlengesi” means dolphin (smaller
animal from the sea) in the native South African Xhosa
language. Gender masculine.
d
iAgnosis. — Same as for the species.
579
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
mesethmoid
median suture
maxillary foramen
maxillary crest
premaxillary crest
premaxillary foramen
premaxillary sac fossa
vomer
maxilla
maxilla
premaxilla
frontal
nasals
frontals
bony nares
A
B
C
D
antorbital notch
maxillary crest
premaxillary crest
fragment of palatine
fragment of palatine
vomer
vomer
maxilla
maxilla
maxilla
premaxilla
premaxilla
premaxilla
premaxilla
frontal
infraorbital foramen
marks of maxilla-palatine suture
marks of maxilla-palatine suture
vomer
vomer
maxilla
frontal
infraorbital foramen
antorbital notch
cerebral cavity
choana
Fig. 13. — Skull of Khoikhoicetus agulhasis n. gen., n. sp. (SAM PQ 2678, holotype): A, dorsal view; B, lateral view; C, ventral view.
Scale bar: 10 cm.
580
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
premaxillary crest
premaxilla
maxillary foramen
ascending
process
of premaxilla
premaxillary
crest
premaxillary crest
maxilla
maxilla
premaxilla
premaxilla
nasal
nasal
nasals
vomer
frontals
frontal
frontal
bony nares
bony nares
mesethmoid
mesethmoid
premaxillary
sac fossa
A B
C
D
Fig. 14. — Vertex of skull of Khoikhoicetus agulhasis n. gen., n. sp. (SAM PQ 2678, holotype): A, dorsal view; B, corresponding line
drawing; C, anterior view; D, corresponding line drawing. Scale bars: A, B, 2 cm; C, D, 5 cm.
Ihlengesi saldanhae n. sp.
holotype. — SAM PQ 2792, partial skull including
the rostrum base, anterior part of the cranium, and the
vertex.
p
ArAtype. — SAM PQ 69673, rostrum with anterior
part of the cranium trawled off Cape Columbine, west
coast of South Africa, Atlantic Ocean. is specimen
was previously referred to cf. Mesoplodon densirostris,
M. grayi, M. australisby Haughton (1956) on the basis
of the location of the premaxillary foramina. is well
preserved rostrum provides additional information for
the species description.
e
tymology
. e holotype was found offshore from
Saldanha Bay, a locality on the west coast of South Africa.
t
ype
locAlity
. — No exact locality. Trawled off Saldanha
Bay, west coast of South Africa, Atlantic Ocean.
d
iAgnosis
. — Ihlengesi saldanhae n. gen., n. sp. dif-
fers from all other Hyperoodontinae in the shortened
premaxillary sac fossa (ratio between measurements 15
and 16 lower than 0.30). It shares with Africanacetus
n. gen., Hyperoodon, and Mesoplodon: the inclusion of
the nasal into the premaxillary crest over at least half
the length of the median margin of the crest and a deep
anteromedian excavation of the nasals. Both characters
are absent in Khoikhoicetus n. gen. and Indopacetus. It
further differs from Africanacetus n. gen. in: smaller size;
maxillary foramen close to the prominental notch at the
rostrum base; roughly flat dorsal surface of the preorbital
process and premaxillary sac fossa not laterally sloping.
e space between the premaxillary crests is wider than
in Hyperoodon and Mesoplodon.
description (Figs 15; 16; tAble 4)
A large part of the elongated and transversely com-
pressed rostrum, higher than wide, is preserved in
SAM PQ 69673. e maxilla is roughly hidden
from the dorsal view for the anterior half of the
rostrum. A slight constriction is seen in dorsal view
at c. 120 mm from the preserved apex. e vomer
fills the mesorostral groove over its whole length.
581
Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
antorbital notch
premaxillary crest
premaxillary crest
premaxillary
crest
premaxillary
foramen
premaxillary sac fossa
vomer
protuberant vomer
median suture on the vomer
maxilla
maxilla
maxilla
premaxilla
premaxilla
nasals
nasals
frontals
bony nares
original dorsal
margin of
mesethmoid
prominental notch
maxillary tubercle
maxillary foramen
maxillary foramen
A
B
C D
mesethmoid
Fig. 15. — Skull of Ihlengesi saldanhae n. gen., n. sp. (SAM PQ 2792, holotype): A, dorsal view; B, lateral view; C, detail of the anterior
view; D, corresponding line drawing. Scale bar: 10 cm.
582
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
mesethmoid
premaxillary foramen
premaxillary
crest
premaxillary
crest
premaxillary sac fossa
vomer
maxilla
premaxilla
maxilla
maxilla
maxilla
median suture on the vomer
nasals
shallow sulci
worn surface
frontals
frontal
bony nares
antorbital notch
prominental notch
A B
C
E
D
Fig. 16. — Ihlengesi saldanhae n. gen., n. sp.: A, B, vertex of skull (SAM PQ 2792, holotype); A, dorsal view; B, corresponding line
drawing; C-E, incomplete skull (SAM PQ 69673, paratype); C, dorsal view; D, anterior view; E, lateral view. Scale bars: A, B, 2 cm;
C-E, 10 cm.
In the holotype, the maximum height and width of
the vomer is reached at the rostrum base; a second
hump at one third of the length of the rostrum
is observed in SAM PQ 69673 (not preserved in
the holotype). A median suture marks the dorsal
surface of the vomer at the rostrum base. In the
holotype, the two premaxillae nearly contact each
other above the mesorostral groove 70 mm anterior
to the antorbital notches, a condition sometimes
observed in Recent Mesoplodon densirostris. e
ventrolateral surface of the rostrum of both speci-
mens is worn.
e prominental notch is wide and roughly as
deep as in Mesoplodon layardii. A reduced maxillary
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Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
foramen opens anterolaterally as a triangular fissure
towards the prominental notch. At the level of the well
developed maxillary tubercle, the preorbital process is
barely convex, lacking a distinct maxillary crest.
e distinctly asymmetric premaxillary sac fossae
are short; the distance between the anterior margin
of the bony nares and the premaxillary foramen
is small. e premaxillary foramen is located in a
shallow depression behind the level of the antorbital
notch. e ascending process of the premaxilla is
strongly constricted in anterior view.
e vertex is moderately elevated. e premaxil-
lary crest is thick and wide, posterolaterally directed.
An oblique transverse groove limits ventrally the
anterior surface of each premaxillary crest. e
thicker right crest overhangs the ascending process.
e lateral margins of the longitudinally elongated
nasals are anteriorly diverging; the anterolateral
corner is distinctly thrust into the medial part of
the premaxillary crest. e anteromedial surface
of the nasals is strongly excavated; it forms a deep
vertical groove between the premaxillary crests. e
naso-frontal suture is convex posteriorly.
Genus Africanacetus n. gen.
type species. — Africanacetus ceratopsis n. gen., n. sp.,
by present designation.
e
tymology
. — From Africana”, the Marine Coastal
Management fishery research vessel, which trawled
three specimens of this genus at the same locality off the
south coast of South Africa, “cetus” from Latin, whale.
Gender masculine.
d
iAgnosis. — Same as for the species.
Africanacetus ceratopsis n. sp.
holotype. — NMR 9991-00001993, a partial skull
including the rostrum and the dorsal part of the cranium
with the vertex.
r
eFerred
specimens
. — SAM PQ 2162, trawled off
Cape coast; SAM PQ 2235, trawled off Cape coast,
Atlantic Ocean; SAM PQ 2708, trawled at 35°01’S,
24°06’E, south coast of South Africa, Indian Ocean,
depth of 914 m; SAM PQ 2709, trawled at 35°01’S,
24°06’E, south coast of South Africa, Indian Ocean,
depth of 914 m; SAM PQ 2713, trawled at 35°01’S,
24°06’E, south coast of South Africa, Indian Ocean,
depth of 914 m; SAM PQ 3002, trawled at 34°50’S
18°14’E, south of Cape Town, depth of 604 m; SAM PQ
3062, trawled off Cape coast; SAM PQ 69683, trawled
off Cape Peninsula, between Cape Point and Slangkop
lighthouse, depth of 160-170 m. Most of the referred
specimens are rostra, usually preserved with the anterior
of the cranium, but lacking the vertex. SAM PQ 69683
is an isolated vertex.
e
tymology
. — From the combination of the following
two Ancient Greek words: “keras(genitive “keratos”),
horn, and opsis”, aspect, appearance. For the protuberant
paired maxillary crests.
t
ype
locAlity
. — No exact locality. Trawled south
west off the South African coast, Atlantic Ocean, depth
less than 600 m.
d
iAgnosis
. — Africanacetus ceratopsis n. gen., n. sp.
differs from all other Hyperoodontinae in: presence of
a dome-like elevated maxillary crest on the supraorbital
process and laterally sloping premaxillary sac fossa. It
shares with Ihlengesi n. gen., Hyperoodon, and Meso-
plodon: the dorsal part of the ascending process of the
premaxilla partly overhanging the bony nares, and the
larger portion of the nasal thrust into the premaxillary
crest, differing in these characters from Khoikhoicetus
n. gen. and Indopacetus. It further differs from Hypero-
odon and Mesoplodon in the wide median separation of
the premaxillary crests.
description (Figs 17; 18; tAble 4)
e robust rostrum is long (rostrum of SAM PQ
2235 originally longer than 671 mm) and elevated,
higher than wide over its entire length. e vomer
fills the mesorostral groove, showing a median su-
ture, between its two thickened lateral walls, on its
posterior part; the vomer is more elevated than the
premaxilla over its complete length. e width of
the vomer in the groove varies within the species,
sometimes occupying most of the dorsal surface
of the rostrum (e.g., SAM PQ 3002). It widens at
mid-length on several specimens. At the contact
with the premaxilla, the vomer usually shows a slight
constriction and therefore the dorsal prominent part
of the vomer slightly overhangs the premaxilla. e
alveolar groove is barely visible.
e lateral margins of the rostrum diverge abruptly
towards the prominental notches, creating a wide
concave dorsal surface of the maxilla at the rostrum
base, with an acute lateral margin. e antorbital
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GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
mesethmoid
antorbital notch
maxillary foramen
dorsal infraorbital
foramen
premaxillary crest
premaxillary
crest
premaxillary crest
premaxillary sac fossa
premaxillary
sac fossa
premaxillary sac fossa
vomer
vomer
vomer
maxilla
maxilla
maxilla
maxilla
maxilla
maxilla
premaxilla
premaxilla
premaxilla
marks of maxilla-palatine suture
nasals
nasals
nasal
frontals
bony nares
maxillary tubercle
median suture on the vomer
prominental notch
premaxillary foramen
dome-like maxillary crest
dome-like
maxillary
crest
dome-like maxillary crest
maxillary foramen
mesethmoid
ascending
process
of premaxilla
A
B
C
D
Fig. 17 – Skull of Africanacetus ceratopsis n. gen., n. sp. (NMR 9991-00001993, holotype); A, dorsal view; B, lateral view; C, anterior
view; D, corresponding line drawing. Scale bar: 10 cm.
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Fossil beaked whales (Mammalia, Cetacea) from South Africa
GEODIVERSITAS • 2007 • 29 (4)
antorbital notch
pterygoid sinus fossa
vomer
vomer
maxilla
maxilla
maxilla
maxilla
maxilla
premaxilla
premaxilla
premaxilla
premaxilla
mesethmoid
premaxillary
crest
premaxillary
crest
premaxillary
crest
premaxillary
crest
nasal
nasal
nasal
nasal
frontals
frontals
bony nares
infraorbital foramen
marks of maxilla-frontal suture
marks of maxilla-palatine suture
marks of maxilla-jugal suture
major palatine foramina
vertical foramina
choana
A
B C
ED
Fig. 18. — Africanacetus ceratopsis n. gen., n. sp.: A-C, skull (NMR 9991-00001993, holotype); A, ventral view; B, detail of vertex in
dorsal view; C, corresponding line drawing. D, E, skull fragment (vertex) of Africanacetus ceratopsis n. gen., n. sp. (SAM PQ 69683);
D, dorsal view; E, corresponding line drawing. Scale bars: A, 10 cm; B-E, 5 cm.
586
GEODIVERSITAS • 2007 • 29 (4)
Bianucci G. et al.
notch, separated from the prominental notch by
a distinct maxillary tubercle, is positioned roughly
at the longitudinal level of the premaxillary fora-
men. Posteromedial to the maxillary tubercle rises
a characteristic elevated dome-like maxillary crest,
not extending onto the rostrum base. e median
slope of the dome is nearly vertical. In several
specimens a large maxillary foramen is transversely
compressed between this crest and the premaxilla,
somewhat more posterior than the premaxillary
foramen.
e premaxillary sac fossa is thicker medially,
laterally lowering as in Mesoplodon layardii. e
ascending process is short and constricted in ante-
rior view; the upper part of its anterior surface
is vertical. e lateral margins of the bony nares
continue parallel dorsally. On the moderately ele-
vated vertex, the premaxillary crest is thick, wide,
and posterolaterally directed. e robust posterior
projection of the premaxilla along the nasal con-
tacts the frontal.
e nasals are distinctly wider anteriorly, with
the anterolateral corner included in the posterior
half of the premaxillary crest. e anteromedian
surface of the nasals is excavated, leaving a large
space between the premaxillary crests. e naso-
frontal suture is W-shaped; the right nasal is longer
than the left. e frontal is much shorter than the
nasal on the vertex.
Genus Mesoplodon Gervais, 1850
t
ype
species
. — Physeter bidens Sowerby, 1804, by
original designation.
o
ther
r
ecent
species
included
. Mesoplodon
bowdoini Andrews, 1908,