Pal~iontologische Zeitschrift 76 (2) 305-316 11 Abb. Stuttgart, Oktober 2002 A new specimen of Salmila robusta (Aves: Gruiformes: Salmilidae n. fam.) from the Middle Eocene of Messel GERALD MAYR, Frankfurt am Main with 11 figures Kurzfassung: Ein neues Exemplar des gruiformen Vogels to 26 different families (see MAYR 2000a for a survey on Salrnila robusta MAYR, 2000 wird aus dem mittleren Eoz~in yon the Messel avifauna and SCHAAL ~ ZIEGLER 1988 for Messel (Deutschland) beschrieben. Es ist unter den am besten general information on the site). Although the descrip- erhaltenen Vogelskeletten, die aus Messel bekannt sind und l~isst bisher unbekannte anatomische Merkmale dieser Art er- tion of most avian taxa from Messel is based on com- kennen. Das neue Exemplar best~itigt die frtihere Feststellung plete skeletons, the osteology of some is only insuffi- (MAYR 2000b), dass Salmila robusta abgeleitete Merkmale vor ciently known due to the poor bone preservation of the allem mit den Cariamae (zu denen die rezenten Seriemas, respective specimens. Among these is the gruiform spe- Cariamidae, geh6ren), sowie den Psophiidae (Trompeterv6gel) cies Salmila robusta which was recently described by teilt. Das Fehlen abgeleiteter Merkmale am Hypotarsus schliegt allerdings eine Klassifikation von Salmila robusta in- MAYR (2000b). nerhalb der Cariamae, wie unter Vorbehalt in der Original- Extant Gruiformes (cranes, rails, and allies) are cur- beschreibung angenommen, aus. Statt dessen sttitzt der gegen- rently classified into eleven families (DEL HOYO et al. w~irtige Kenntnisstand am ehesten eine Schwestergruppen- 1996), and in the original description, Salmila robusta beziehung zwischen Salmila robusta und den Cariamae. Zu- was tentatively assigned to the Cariamae, a taxon which sammen mit den morphologischen Besonderheiten der eoz~inen Art rechtfertigt dies eine Klassifikation yon Salmila robusta in includes the South American Cariamidae (seriemas, two eine neue Familie, Salmilidae n. fam. extant species in two genera) and the extinct families Idiornithidae (Eocene and Oligocene of Europe), Schlfisselw6rter: Fossile V6gel, Messel, Eoz~in, Gruiformes, Cariamae, Phylogenie, Salmilidae n. ram. Bathornithidae (Upper Eocene to Miocene of North America), and Phorusrhacidae (Eocene of Europe, Terti- Abstract: A new specimen of the gruiform bird Salmila ary of South America, Pleistocene of North America), as robusta MAYR, 2000 is described from the Middle Eocene of Messel (Germany). It is among the best preserved bird skel- well as several other poorly known fossil families etons known from Messel, and allows the recognition of previ- (BRODKORB 1967; CRACRAFT 1968; MOURER-CHAUVIRI~ ously unknown anatomical features of this species. This new 1981, 1983). A phylogenetic assignment of Salmila specimen confirms previous observations (MAYR 2000b), that robusta was especially difficult because of the fact that Salmila robusta shares derived characters mainly with the important osteological features are not visible in the Cariamae (to which the extant seriemas, Cariamidae, belong) and the Psophiidae (trumpeters). However, the absence of de- specimens described by MAYR (2000b), and that the spe- rived features of the hypotarsus precludes classification of cies shares most derived similarities not only with the Salmila robusta within the Cariamae, as tentatively proposed Cariamae but also with the, likewise South-American, in the original description. Instead, present evidence rather sup- Psophiidae (trumpeters, three extant species in a single ports sister group relationship between Salmila robusta and the genus). Cariamae. Together with the morphological distinctness of the Eocene species, this justifies classification of Salmila robusta Described in this study is a new specimen of Salmila into a new family, Salmilidae n. fam. robusta which was recently acquired from a private col- lection by the Hessisches Landesmuseum, Darmstadt, Keywords: Fossil birds, Messel, Eocene, Gruiformes, Cariamae, phylogeny, Salmilidae n. fam. Germany (HLMD), and which was not available at the time the original description was prepared. It is among the best preserved bird skeletons found in Messel so far, Introduction and allows the recognition of previously unknown ana- In the last decades, excavations of the Middle Eocene tomical features. Salmila robusta apparently is the sister deposits of Messel near Darmstadt (Hessen, Germany) taxon of several other recent and fossil families (see dis- yielded several hundred avian skeletons, which offer an cussion), and together with the morphological distinct- unique insight into the early evolution of birds. So far, ness of the Eocene taxon this justifies its classification more than 30 species have been described which belong into a new family. Address of the author: Dr. GERALD MAYR, Forschungsinstitut Senckenberg, Division of Ornithology, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany; e-mail <[email protected]> 0031-0220/02/0076-0305 $ 3.00 © 2002 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart 306 GERALD MAYR Material and methods Description and comparison (only those features are mentioned which were not already described by MAVR 2000b): The fossil specimen is deposited in the Hessisches Landesmuseum, Darmstadt, Germany (HLMD). If not Skull (Fig. 3): Few additional details of the skull can be indicated otherwise, the anatomical terminology follows seen in the new specimen. Again, it cannot be discerned BAUMEL & WITMER (1993). The dimensions are in milli- with certainty whether the beak was holorhinal as in ex- meters and refer to the maximum length of the bone along tant Cariamidae and Psophiidae, or schizorhinal as in its longitudinal axis. Osteological comparisons have been some of the other gruiform taxa. The narial openings made with representatives of all recent gruiform families seem to have been more elongated than in extant except for the Heliornithidae (finfoots), of which no skel- Psophiidae and Cariamidae, but on the other hand the etons were available. processus praemaxillaris of the os nasale (Fig. 3) appears A cladistic analysis with the phylogenetic software to have been wider than in typical schizorhinal birds, e.g. PAUP, version 3.1 (SwOFFORD 1993) was performed us- Eurypygidae (sunbittern) and Gruidae (cranes). As in all ing a data matrix of 35 anatomical characters (see Ap- other gruiform birds, the internarial septum was not ossi- pendices I and II for character descriptions and data ma- fied. The ossa lacrimalia apparently lack well developed trix). The shortest tree was found with the exhaustive processus supraorbitales which are also absent in extant search option and the analysis was run with the delayed Psophiidae but present in the Cariamidae and Phorusr- transformation (DELTRAN) mode; consistency index hacidae (the bathornithid Bathornis grallator also seems (CI), retention index (RI), and rescaled consistency in- to lack these processes, see WETMORE 1944 and OLSON dex (RC) were calculated. The robustness of the tree was 1985; the skull of other fossil Cariamae has not yet been tested with a bootstrap analysis of 1000 replicates. described). The processus postorbitalis is visible next to the right radius and closely resembles that of the Psophiidae (Fig. 3). Systematic Palaeontology Trachea: Contrary to the other two known specimens of Class Aves LINNAEUS, 1758 Salmila robusta, in HLMD.Be. 161 an ossified trachea is Order Gruiformes BONAPARTE, 1854 preserved. Salmilidae n. fam. Type genus: Salmila MAYR,2000. Vertebrae: Salmila robusta had a fairly short neck; as in Other included genera: None. most other gruiform birds, the most caudal cervical ver- tebrae bear processus ventrales. It is not clearly visible Diagnosis: Medium-sized birds with (1) furcula very ro- whether the thoracic vertebrae were fused to form a bust; (2) coracoid without well developed foramen nervi notarium as in recent Psophiidae, Gruidae, Eurypygidae, supracoracoidei; (3) humerus robust and stout, and with and Rhynochetidae (kagus), although it seems to be more large proximal end; (4) sternum with short margo likely that they were not (the corresponding vertebrae are costalis, one pair of deep incisions in margo caudalis, and overlain by the sternum and are thus not directly visible, tapering trabecula mediana; (5) ulna stout, not exceeding however they appear to have been slightly displaced humerus in length, and with very short olecranon; (6) against each other). The free thoracic vertebra directly carpometacarpus with portion of trochlea carpalis be- cranial of the synsacrum lacks a processus ventralis (this tween processus pisiformis and os metacarpale minus vertebra bears a process in Psophia and a low ridge in distinctly raised; (7) os metacarpale minus bowed, with Cariama); it further exhibits a well developed pneumatic proximal end bearing a small tubercle on its ventral side; foramen on each side of the corpus vertebrae (these fora- (8) tarsometatarsus not exceeding ulna in length; (9) mina are also present on the corresponding vertebra of hypotarsus with cristae medialis et lateralis hypotarsi extant Psophiidae and Gruidae, but absent in the Caria- separated by distinct sulcus; (10) proximal end of first midae). Seven free tail vertebrae can be discerned, and phalanx of fourth toe with large, medially directing pro- this number was considered to be primitive within jection. Gruiformes by LIVEZEY (1998: 2111). The pygostyle is At least the latter character probably is autapomorphic large