The Auk 117(4):964-970, 2000 TINY HOOPOE-LIKE BIRDS FROM THE MIDDLE EOCENE OF MESSEL (GERMANY) GERALD MAYR • ForschungsinstitutSenckenberg, Sektion fiir Ornithologie,Senckenberganlage 25, D-60325 Frankfurta.M., Germany ABSTRACT.--Tinyhoopoe-like birds of the extinctfamily Messelirrisoridaeare amongthe predominantsmall perching birds in the Middle Eocene(ca. 49 million yearsago) avifauna of Messel(Hessen, Germany). Members of the Messelirrisoridaeare the earliest-knownrep- resentativesof the hoopoe/wood-hoopoelineage and are sistertaxa of recentUpupidae (hoopoes)and Phoeniculidae(wood-hoopoes). Outgroup comparison with the Messelirri- soridaefacilitates character-state analysis within the Phoeniculidaeand Upupidae.In this study,I describea new species,Messelirrisor grandis, which is the largestspecies of the Mes- selirrisoridaeknown so far. Received31 August1999, accepted 28 April 2000. THE FORMER OPENCAST oil-shale mine "Gru- daepredominate. So far, two speciesin a single be Messel" is located a few kilometers north- genushave beendescribed, Messelirrisor halcy- eastof Darmstadt in Hessen,Germany. Accord- rostrisand M. parvus(Mayr 1998). Both are ing to the currentlyfavored hypothesis, the de- known from severalcomplete articulated skel- positsof Messeloriginated in a deepcrater lake etons preserved on slabs, and both are very of tectonicorigin about49 million yearsago in small,more diminutiveeven than many recent the LowerMiddle Eocene.The sitehas yielded hummingbirds(Fig. 1). Here,I describea third a large number of vertebratefossils in an ex- speciesfrom the Messelirrisoridae,the largest ceptionalstate of preservation;in many cases, known so far. the remains of former soft tissues and stomach The fossil specimensare depositedin the contentshave been preserved (see Franzen Geiseltalmuseum,Halle, Germany(GMH), the 1985,Schaal and Ziegler 1988).In 1995,Messel ForschungsinstitutSenckenberg, Frankfurt was declareda world heritagesite by UNESCO. a.M., Germany (SMF), and in the Staatliches In terms of the number of individual skele- Museum fiir Naturkunde,Karlsruhe, Germany tons and the number of species,birds are (SMNK). Measurementsreported below rep- among the most abundant land vertebrates resentthe overalllength along the longitudinal found in Messel. In recent decades, several axis. Anatomical terminology follows Baumel hundredbird skeletonswere discovered,many and Witruer (1993)unless indicated otherwise. of them completeand articulated.The avifauna is very diverse,and thusfar about50 avianspe- SYSTEMATICS cieshave been identified. Among these are ibis- es (Peters1983), swifts (Peters1985, Mayr and Hoopoe-likebirds comprisetwo recentfam- Peters1999), parrots (Mayr and Daniels 1998), ilies, the PalearcticUpupidae (hoopoes)and and frogmouths(Mayr 1999).Contrary to near- the African Phoeniculidae(wood-hoopoes), ly all other sitesthat haveyielded fossilbirds, and generallyare classifiedtogether with roll- even extremely small bird skeletonsare pre- ers, kingfishers,bee-eaters, todies, and mot- servedin Messelin greatnumbers. motsin the orderCoraciiformes (see Sibley and Passeriformsare completelyabsent in theEo- Ahlquist1990:336-348). Yet, because the mono- ceneavifauna of the NorthernHemisphere, at phyly of thisorder has never been convincingly which time the ecologicalniches for small established with derived characters, I use the perchingbirds were occupiedby representa- term Upupiformes(sensu Feduccia 1977, Sibley tives of other avian taxa (Harrison 1979, Olson and Ahlquist 1990)for hoopoe-likebirds. 1989, Feduccia1996). In Messel,tiny hoopoe- Monophylyof the Upupiformesis supported like birds of the extinct family Messelirrisori- by the following charactersthat are unique among.neognathous birds: shaft of ulna with E-mail: [email protected] projection distal to cotyla dorsalis (Fig. 2, no. 964 October2000] Hoopoe-likeBirds from Messel 965 1 Moraotus momotus Upupa epops FIG. 2. Proximal ulna of Momotusmomotus (Mom- otidae,left) and Upupaepops (right). (1) Projectionbe- low theprocessus cotylaris dorsalis that is synapo- rnorphic for the Messelirrisoridae,Upupidae, and Phoeniculidae. Scale bar = 5 mm. irregularlyshaped (unique among neognath- ous birds); (3) spina externa and spina interna of sternum fused to form a spina communis (onlyin very few otherneognathous birds, e.g. Meropidaeand someBucerotidae); (4) sternum with onlyone pair of incisions(the two pairsof the Messelirrisoridaegenerally are considered to be plesiomorphicwithin neognathousbirds; e.g. Olson 1987);and (5) phalanxproximalis FIG. 1. Messelirrisorparvus (SMNK PAL 3802), digiti majoris hooked (among other recent slightlydisarticulated with detachedskull and cer- neognathousbirds only in Galbulidaeand Buc- vical vertebrae.Specimen is coatedwith ammonium conidae; Fig. 3, no. 3). Recent upupids and chloride to enhance contrast. Scale bar = 10 mm. phoeniculidsalso share a derived stapedial morphology(Feduccia 1975). 1); carpometacarpuswith osseousridge from The new speciesdescribed below exhibits all ventral margin of os metacarpaleminus to pro- of the above-mentioned derived characters of cessuspisiformis (Fig. 3, no. 1); and caudal the Upupiformesand lacksthose of the Upu- margin of os metacarpaleminus (carpometa- pidae and Phoeniculidae.Especially the hu- carpus)undulated (only slightlyin Messelirri- merusand the carpometacarpusof the Messe- soridae;Fig. 3, no. 2). Apart from their much lirrisoridaeare highly characteristicand can smaller size, messelirrisoridsclosely resemble hardlybe mistakenwith thoseof anyother avi- Upupidaeand Phoeniculidaein manyother os- an taxon(see below). Apart from its largersize, teologicalfeatures: (1) long,pointed, and at the the new speciesvery closelyresembles the oth- basedorsoventrally high beak;(2) presenceof er speciesof the genusMesselirrisor in its os- largeprocessus retroarticulares on the mandi- teology. ble; (3) shapeof the extremitasomalis of the furcula;(4) absenceof an apophysisfurculae; Messelirrisorgrandis sp. nov. (5) stouthumerus; (6) proportionsof limb ele- ments;and (7) longhallux. Holotype.--SMNK PAL 3803 (sternum, pec- The upupidsand phoeniculidsare united to toral girdle and both wingson a slab;Fig. 5). the exclusion of the Messelirrisoridae because Diagnøsis'--Messelirrisørgrandis is thelargest the formertwo familiesshare the following de- speciesof the Messelirrisoridaeknown so far rived characters:(1) margo medialisof cora- (Table1). It is further distinguishedfrom M. coid with distinctmedially projectingprocess parvusand M. halcyrostrisin the slightlymore (Figs.4A-C, no. 1; uniqueamong neognathous cranially situatedprocessus pisiformis of the birds); (2) processuslateralis of coracoidvery carpometacarpus. 966 GERALDMAYR [Auk, Vol. 117 Messelirrisorhalcyrostris Upupa epops FIC.3. Left manusof Messelirrisorhalcyrostris (after Mayr 1998)and Upupaepops. (1) Ridgefrom the ven- tral side of the os metacarpaleminus to the processuspisiformis; (2) undulatedcaudal margin of the os metacarpaleminus; (3) hookeddistal end of phalanxproximalis digiti majoris.Scale bar = 5 mm. Typelocality.--Messel near Darmstadt (Hes- dorsoventrally,and the culmen is slightly sen, Germany). curved.The narial opening is longand slit-like, Typehorizon.--Lower Middle Eocene(Legen- and the rami mandibulae are wide dorsoven- dre and L•v•que 1997). trally. Measurementsofholotype.--Coracoid, about 12 Like in other messelirrisorids,the extremitas mm; left humerus,19.3 mm, right humerus, omalisof the furculais rhombicin shape(more 20.1 mm; ulna, about24 mm; carpometacarpus, round in recentUpupiformes), and the scapus 10.7 mm (Table 1). claviculaeis slender.The scapulais shortand Referredspecimen.--SMF-ME 600, a largely straight.The acromionis alsoshort and bears completebut poorlypreserved skeleton on two a small projectionon its ventral side. The ex- slabs,from the type localityand horizon(Fig. tremitasomalis of the coracoidis hidden by 6). overlyingbones in the type specimen.The pro- Measurementsof referred specimen.--Skull, cessus lateralis of the extremitas sternalis is about 41.5 mm; coracoid, about 12 mm; hu- narrow but long. A small notchoccurs on the merus, about 20 mm; ulna, about 23 mm; car- medial side of the extremitas sternalis. pometacarpus,about 10 mm; tibiotarsus,about The sternumis slightlylonger than wide and 19 mm; tarsometatarsus, about 10.4 mm. bearsshort processus craniolaterales. Its lateral Etymology.--Thespecific name has been de- marginsare somewhatcurved, and the margo rived from Latin grandis,large, and refersto costalis is short. Like in other messelirrisorids, thelarge size of thenew species compared with the othertwo speciesof messelirrisorids. the margocaudalis bears two pairsof incisions, whereasrecent Upupiformes have only one pair The incisionson the right sideof the ster- REMARKS num are nearlyequal in depth(about one-third The skull is preservedin the referredspeci- the lengthof the sternum),and on the left side men SMF-ME600, but owing to the flattening the incisuramedialis is slightlydeeper. The in- of the bones,details of its morphologycan cisurae laterales are narrower than the incisu- hardly be discerned.In its shape,however, it rae mediales. The trabeculae laterales are wide, matches well with the skull of other messelir- and the trabecula mediana is triangular in risorids.This is especiallytrue for the longand shape. pointedbeak, which is about1.5 timeslonger The humerusis shortand stoutwith a large than the cranium.The beakis high at its base proximal end and a slightly curved,