Systematics and phylogeny of the fossil beaked whales Ziphirostrum du Bus, 1868 and Choneziphius Duvernoy, 1851 (Mammalia, Cetacea, Odontoceti), from the Neogene of Antwerp (North of Belgium) Olivier LAMBERT Institut royal des Sciences naturelles de Belgique, Département de Paléontologie, rue Vautier, 29, B-1000 Brussels (Belgium) [email protected] Lambert O. 2005. — Systematics and phylogeny of the fossil beaked whales Ziphirostrum du Bus, 1868 and Choneziphius Duvernoy, 1851 (Mammalia, Cetacea, Odontoceti), from the Neogene of Antwerp (North of Belgium). Geodiversitas 27 (3) : 443-497. ABSTRACT A systematic revision of the fossil beaked whales (Cetacea, Odontoceti, Ziphiidae) Ziphirostrum du Bus, 1868 and Choneziphius Duvernoy, 1851 from the Neogene of Antwerp (Belgium, southern margin of the North Sea Basin) is undertaken. It is based on several rostra and partial skulls from the collection of the Institut royal des Sciences naturelles de Belgique. From the previous conclusions about those taxa, dating from the beginning of the 20th century and suggesting only one species in each genus, Mioziphius ( Ziphirostrum) belgicus and Choneziphius planirostris, the following modifica- tions are proposed. The genus Ziphirostrum includes three species: Z. mar- ginatum, Z. turniense, and Z. recurvus n. comb. Basicranial fragments and teeth of Z. marginatum are described for the first time. Besides the most com- mon species Choneziphius planirostris, the species C. macrops is identified from Antwerp and the east coast of North America. A new genus and species KEY WORDS Mammalia, Beneziphius brevirostris n. gen., n. sp. is described on the basis of two specimens Cetacea, characterized by a short and pointed rostrum. Two partial skulls are placed in Odontoceti, Ziphiidae aff. Eboroziphius, a genus known from the east coast of North Ziphiidae, Ziphirostrum, America. The genus name Aporotus is restored, with a large species A. recurvi- Choneziphius, rostris, and a smaller species A. dicyrtus. A parsimony analysis including fossil Miocene, Pliocene, and extant ziphiid taxa shows a sister-group relationship between Belgium, Choneziphius + ( Tusciziphius + Ziphius) and Ziphirostrum + Beneziphius fossil, n. gen. The poorly known Aporotus seems more closely related to Chone- phylogeny, new genus, ziphius + ( Tusciziphius + Ziphius), but additional morphological information new species. is needed. GEODIVERSITAS • 2005 • 27 (3) © Publications Scientifiques du Muséum national d’Histoire naturelle, Paris. www.geodiversitas.com 443 Lambert O. RÉSUMÉ Systématique et phylogénie des baleines à bec fossiles Ziphirostrum du Bus, 1868 et Choneziphius Duvernoy, 1851 (Mammalia, Cetacea, Odontoceti) du Néogène d’Anvers (nord de la Belgique). La révision des baleines à bec fossiles (Cetacea, Odontoceti, Ziphiidae) Ziphirostrum du Bus, 1868 et Choneziphius Duvernoy, 1851 du Néogène d’Anvers (Belgique, bord sud du Bassin de la mer du Nord) est basée sur une série de rostres et de crânes partiels de la collection de l’Institut royal des Sciences naturelles de Belgique. À partir des conclusions systématiques pré- cédentes, datant du début du XXe siècle et suggérant une seule espèce dans chaque genre, Mioziphius ( Ziphirostrum) belgicus et Choneziphius planirostris, les modifications suivantes sont proposées. Le genre Ziphirostrum inclut trois espèces : Z. marginatum, Z. turniense et Z. recurvus n. comb. Des fragments du basicrâne et des dents de Z. marginatum sont décrits pour la première fois. À côté de l’espèce la plus commune Choneziphius planirostris, C. macrops est identifié à Anvers et sur la côte est de l’Amérique du Nord. Le nouveau genre et espèce Beneziphius brevirostris n. gen., n. sp. est décrit sur MOTS CLÉS Mammalia, la base de deux spécimens caractérisés par un rostre court et pointu. Deux Cetacea, crânes partiels sont considérés comme Ziphiidae aff. Eboroziphius, un genre Odontoceti, connu de la côte est de l’Amérique du Nord. Le nom de genre Aporotus est Ziphiidae, Ziphirostrum, rétabli, incluant une grande espèce, A. recurvirostris, et une plus petite, Choneziphius, A. dicyrtus. Une analyse de parcimonie incluant des genres fossiles et actuels Miocène, Pliocène, de ziphiidés montre un lien de groupes-frères entre Choneziphius + Belgique, ( Tusciziphius + Ziphius) et Ziphirostrum + Beneziphius n. gen. Le genre fossile, moins bien connu Aporotus semble plus proche de Choneziphius + phylogénie, nouveau genre, ( Tusciziphius + Ziphius), mais des informations morphologiques complé- nouvelle espèce. mentaires seraient nécessaires. INTRODUCTION The first species described from Antwerp by Cuvier (1823) were Choneziphius planirostris and The extant beaked whales (family Ziphiidae), Mesoplodon longirostris. The original skulls were including 21 species in six genera, considered for found between 1809 and 1812 during the exca- at least a part of them as deep-diving feeders, are vation of docks (Van Beneden 1864), and are among the least known of all mammalian groups now preserved at the Muséum national (Wilson 1992); some of the species are only d’Histoire naturelle, in Paris. known by several specimens. Well preserved Most ziphiids were discovered in the second part fossil ziphiids are also rare. The Neogene of of the 19th century, during the building of fortifi- Antwerp (North of Belgium, southern part of the cations around Antwerp. In 1860, Van Beneden North Sea Basin) is probably the richest location reported a head of “Cétacé ziphioïde”, which he where diagnostic specimens of ziphiids have been named Dioplodon d’Hemixem. This skull, with the discovered, with several genera based on species posterior part detached but preserved, was proba- from the sequence. bly lost before 1900 (Abel 1905). In 1864, Van 444 GEODIVERSITAS • 2005 • 27 (3) The Neogene ziphiids Ziphirostrum and Choneziphius (Cetacea, Odontoceti) Beneden changed the genus name Dioplodon in A BBREVIATIONS Ziphirostre, again without descriptions or identifi- ED Specimen given by E. Delheid to the IRSNB; cation number. In his work of 1868, du Bus used IRSNB Institut royal des Sciences naturelles de the genus name Ziphirostrum for five poorly de- Belgique, Brussels; scribed species of ziphiids, without reference to MCollection of types and figured specimens the species named by Van Beneden. However, of fossil mammals from the IRSNB; MGPD Museo di Geologia e Paleontologia several labels of skulls, written by du Bus in the dell’Università di Padova; 1860s, bear the name “ Ziphirostrum hemixemii, MNHN Muséum national d’Histoire naturelle, Van Ben.” (Abel 1905). Du Bus (1868) also creat- Paris; ed several new ziphiid genera: Aporotus with three MP Museo di Storia Naturale e del Territorio Certoso di Calci dell’Università di Pisa; species, Ziphiopsis with two species, and NMB Natuurhistorisch Museum Boekenberg, Rhinostodes with one species. Further, he named a Antwerp; new species in Belemnoziphius Huxley, 1864. USNM United States National Museum of Natural Several of these taxa were subsequently briefly dis- History, Washington DC; ZMA Zoölogisch Museum of Amsterdam. cussed in Owen (1870). Later, Abel (1905) reduced the many nominal species of Ziphirostrum, Aporotus, and Ziphiopsis, in a manner quite similar to his work on eurhino- MATERIAL AND METHODS delphinids, to one species in one genus, Mio- ziphius belgicus (except a skull of Ziphiopsis S PECIMENS. — Most of the specimens described or re- described in this work are from the collection of the phymatodes, placed in Choneziphius planirostris). IRSNB. Some of them have never been figured and Abel considered the range of variation briefly de- did not belong to the collection of types and figured scribed by du Bus (1868) to be intraspecific onto- specimens. Some of them were exhibited in the genetic variation. He further included in Museum of the IRSNB in the past, but most were not available for study since the time of Abel (around Mioziphius belgicus the fragmentary mandibles of 1905). The lists of numbered specimens given by Abel Synostodon sensu du Bus (in Vanden Broeck 1874: (1905: 104, 109 and 116) were used to identify the 147), totaling 49 partial skulls and mandibles for specimens described by du Bus (1868) for which the one species, Mioziphius belgicus. Mioziphius is a labels were lost or not readable. junior synonym of Ziphirostrum (e.g., Muizon T ERMINOLOGY. — The main anatomical terms desig- 1984, 1991; Bianucci et al. 1992; McKenna & nating the different bony and soft parts of the ziphiid head are taken from the review of Heyning (1989a). Bell 1998; Fordyce & Muizon 2001). On the basis of a fragment of mandibular symph- D ESCRIPTION OF THE MEASUREMENTS. — See Figure 1 ysis lacking teeth, du Bus (1872) proposed the and Tables 1-6. species Champsodelphis scaldensis, identified as a ziphiid by Abel (1905), who named it Palaeo- ziphius scaldensis. Abel (1905) also placed another SYSTEMATICS fragment of symphysis in Cetorhynchus atavus. Those species, based on isolated mandibles, will Order CETACEA Brisson, 1762 not be discussed here. Suborder ODONTOCETI Flower, 1867 The subject of this paper is a systematic revision of the numerous specimens of Ziphirostrum and Family ZIPHIIDAE Gray, 1865 Choneziphius from the collections of the IRSNB, addressing the opinions of du Bus (1868) and T YPE GENUS.—Ziphius Cuvier, 1823. Abel (1905) on that subject. This part is followed by a discussion of the phylogenetic relationships I NCLUDED GENERA. — The extant genera Berardius Duvernoy, 1851, Hyperoodon Lacépède, 1804, of the revised