Notes on the Phylogeny of the Pelecaniformes

Vol.•94764] .I LaNaaM,Phylogeny o[ the Pelecani[ormes 65

NOTES ON THE PHYLOGENY OF THE PELECANIFORMES

BY URLESS N. LANHAM CERTAINaspects of the phylogenyof the order Pelecaniformesare obscuredby the arrangementof its three living subordersin fi•e standardclassifications. The sequenceas givenby Wetmore (1940) and Peters (1931)is: PHAJ•THONTES(Tropic-birds), PELECANI (Peli- cans, Boobies, Cormorants, Snake-birds),and FREGATAE(Frigate- birds). The tropic-birdsand œrigate-birds,although widely divergent, showbasic structural similaritieswhich indicate both to be primitive members of the order, and which link the order with the Pro- cellariiformes. The fundamentalsimilarity of Phagthonand Fregatahas been rec- ognizedin the olderwork on the comparativeosteology of the group. Mivart (1878),from a studyof the axial skeleton,came to the con- clusionthat Phagthonand Fregatapossessed common characters which sharplydistinguished them from the other steganopodes,and, in fact, could find no charactersto unite them with the rest of the stegano- podousgenera to form a natural group. The generalizedcondition of the cervicalvertebrae of thesetwo genera,in contrastto the spe- cialization in the rest of the order, and certain primitive skull characters are largely self-evidentand may have escapedemphasis for this reason. Shuœeldt(1894) statesthat" . . . Steganopodesare more closelyconnected with the Tubinares than they are with the Longi- pennes." Murphy (1936) recognizesthe generalizedcharacter of the skull of Pha•'thon, and the affinity of the Pelecaniformeswith the Procellariiformes;these two facts, at least, are implicit in modern classifications. The more obvious skeletal characters common to Pha•'thon and Fregata,and commonalso to the procellariiforms,may be summa- rized as follows: ¾omerpresent; maxillopalatines forming two conspicuousseparate lobes on the palatal surfaceof skull near anterior end of palatines;occipital condyle well un- derneath skull, so that condyle is anterior to coronal crest. Fifteen cervical vertebrae present;normal, with serial changein shapegradual. Correspondingcharacters of the suborderPelecani are: Vomer absent;maxillopalatines not visibleon palatal surface,or (in Pelecanu$) visible on surfaceand lobed, but fused in midline and reduced. Occipital condyl½ in line with or posteriorto the coronal crest. Seventeento twenty cervical vertebrae; articulation of cervical vertebrae peculiar, eighth or ninth pressedback at pre-axial end; posteriorforking of neural archesappearing suddenly on seventh or eighth vertebrae. The relationshipof Phagthon and Fregata to each other and to 66 LANHAM,Phylogeny o[ the Pelecani[ormes i.J-Auk Jan.

T•XT-F•GU• 1.--Phylogeny of the Pelecaniforrnes. the Procellariiformesis further suggestedby the fact that all gen- erally lay a singleegg (usuallytwo or more in the Pelecani). Axial skeletoncharacters listed by Mivart (1878)as indicating the affinityof Phab'thonand Fregatainclude the very large acetabular fossaeof thesetwo genera (as comparedwith the moderateor small fossaein other pelecaniforms),the completelack of haemalarches on any of the vertebrae (presenton some vertebrae in the rest, al- thoughincomplete in Phalacrocorax),and the shapeof the post- acetabularpart of the ileum,described as being broad and dorsally convex,arching backwards and downwardin a waynot foundin the rest of the order. Thestriking difference in beak structure of thetwo genera-simple and tern-likein Phab'thon,compound and albatross-likein Fregata-- couldbe comparedto a similar(although less marked) difference in beak structurebetween the anhingasand cormorants,which are without doubt closelyallied. In this view, the beak structureof Phab'thonand .4nhinga would represent independent specializations. Of greater significanceare anatomical differenceswhich indicate a longperiod of separationof Phab'thonand Fregatastocks. Data on musculaturegiven by Beddard (1898) include:leg musculature .4XY-- in Pha•thon (althoughBeddard was unable to find the am- biensin this genus,he statesthat Fiirbringerand Gadowmark it as present),.4-{- in Fregata,biceps slip presentin Pha•thon,absent in Fregata.The sternumof Pha•thonhas two notches and processes Vol.õ4'] LA•IAM,Phytogeny of the Petecanfformes 67

posteriorly,while that oœFregata is truncate. There are alsodiffer- encesin the articulation oœthe pectoral girdle. The basic similarities oœthe Pha•thontes and Fregatae raise the questionas to whetheror not the two shouldbe mergedinto a single suborder. Coues (1903) gives the essentialœacts which justiœythe separationoœ the two into separatesuborders in stating that the families "Pha•thontidae and Fregatidae differ as much œromeach other as both do œromthe other œour--Phalacrocoracidae,Anhingi- dae, Sulidae, and Pelecanidaebeing more closelyrelated to one another. Such inter-relationshipsmight serveœor œormal division oœ the order into three suborders..." Iœ the formal classification were to expressperfectly the supposedphylogency oœ the order, as illus- trated in the accompanyingdiagram, then a pair oœnames oœ the samegrade oœcategory would have to be applied to each branch. Phagthonand Fregata taken togetherwould then constitutea taxo- nomic categoryequivalent to the rest oœthe order taken together. An inspectionoœ the diagramwill showœurther that two other grades oœcategories between suborder and œamilyrank would have to be suppliedto expressthe detailsoœ phylogeny. Sucha œormalclassi- ficationwould not, however,give any direct indicationoœ the relative degreesoœ difference existing between the œamilies. It would seem better to strike an averagebetween the demandsoœ phylogeny and relativedifference by retainingthe threesuborders (meeting the latter requirement),and by altering the sequence,so that Fregataefollows Pha•thontes(meeting the requirementsoœ phylogeny). When expressingthe phylogenyoœ a group in the manneroœ the diagramgiven here, with the primitive membersto the left and the dominant,more evolutionallyactive membersto the right, the de- greeof morphologicdifference between the samegrade oœ category will in a generalway decreaseœrom leœt to right. This is probably the result oœlonger operationoœ œactors producing divergence, or apparentdivergence (extinction oœ annectant œorms), in the more ancient groups. Although Phagthonand Fregata differ widely œromthe Pelecani, there seems to be little doubt that the three constitute a natural order. Anatomicalcharacters such as the absenceoœ basipterygoid processes (Beddard,1898: 409, thinks certain processeson the skull oœPele- canusru[escens may be rudimentsoœ the basipterygoidprocesses) and the totipalmateœoot are strengthenedby other similarities. All (except Phagthon)have similar eggs,and all (except possiblysome anhingas)are fish-eaters.Murphy (1936) has pointed out the simi- larity oœthe youngin all œamilies,and notesthat the youngFregata 68 LANHAM,Phylogeny of thePelecani[ormes L[-Auk Jan. is long-legged.In addition,the fossilProphagthon seems to be in- termediatein somerespects between Phak'thon and the rest of the steganopodes(Lainbrecht, 1933), servingto unify the group. Pelicanscan be regardedas a specializedbranch in which the ambienshas been lost, but in which the primitive maxillo-palata structurehas been to some extent retained. In the superfamily Sulides,the ambiensmuscle is retained (exceptpossibly in some speciesof cormorants),and the maxillopalatinesare not evidentparts of the palatal surface. The Sulidae may be differentiatedfrom the cormorantsand anhingasby the fusionof the lachrymalsto the skull, and (Beddard, 1898: 405) by the presenceof 18 cervicalvertebrae (20 in the cormorantsand anhingas). The Phalacrocoracidaeand Anhingidaeare the most closelyrelated families of the order. Cor- morantsare the leastspecialized of the two. Anhingashave a spear- like beakwith serratedmargins, and havelost the right carotidartery. The geographicaldistribution of the order is that of an ancient group, and perhapswas accomplished,at least as far as continental distributionwas concerned, by early Tertiary times. The continental families Pelecanidaeand Anhingidae are found on all the major land masses.All familiesare representedin Australasia.Anhingidae are the most land-boundof the order, and the remainingfamilies, arranged in order of increasinglygreater oceanicdistribution are (Murphy, 1936) Pelecanidae,Phalacrocoracidae, Fregatidae, Sulidae, and Pha•thontidae. The last are truly pelagic. Fossil representativesof the Pelecaniformesare fairly numerous, and indicate the group to be an ancient one, being well diversified at the beginningof the Tertiary. The suborderOdontopteryges, from the Eocene,had tooth-likeserrations on the marginsof the beak; it is generallyagreed that they did not possestrue teeth. Odontop- teryx, the type genus,is steganopodousin character,but cannot be referred to any of the living subdivisionsof the order. Pseudodon- tornis,of unknownage, also had tooth-likepegs in the beak, and wasevidently a large fish-eatingbird. It is referredprovisionally to the order by Lainbrecht (1933). Propha•thon,of Eoceneage, is in- termediatein many respectsbetween the suborderPhaethontes 'and the rest of the Pelecaniformes.Cyphornis and Paleochen6ides,from the Mioceneof North America,are referredby Wetmore (1928)to a singlefamily, Cyphornithidae,which is mostnearly related to the pelicans. Cyphorniswas a giganticbird, about twice as large as a modern pelican. Both generashow suloid characters,and are some- what intermediatebetween the superfamiliesPelecanoidea and Suloi- Vol.•94764] -• ' LANHAM,Phylogeny o! the Pelecaniformes 69 dea. The generaPelagornis (Miocene) and Argillornis(Eocene) are placedby Lambrechtin the supeffamilySuloidea; they showsome relationshipto Sula. For convenience,both may be put arbitrarily into a single family, Pelagornithidae.The family Elopterygidae containsthree genera:Elopteryx (Cretaceous),Eostega (Eocene), and Actiornis(Eocene). They showrelationship to both the Sulidaeand Phalacrocoracidae.The family may provisionallybe consideredas an intermediategroup. Miosula, placed in the Sulidae,is annectant betweenthe gannetsand cormorants,as Miller (1925), has point•l out. Fossilcormorants, hardly different from living genera,are found in the Oligocene. Protoplotus,from the early Tertiary (probably Eocene),is referred by Lambrecht to the Anhingidae. This early differentionof the anhingidstock implies the existenceof cormorants in early Tertiary times, since the anhingidswere undoubtedlyde- rived from them. The relationshipbetween the Pelecaniformesand Procellariiformes is of sucha nature as to suggestthe iormer to have been derivedfrom a primitive procellariiformstock. It seemslikely that the broad lines of phylogenesiswere accomplishedin Crataceoustimes. A hypotheticalphylogeny is presentedin the accompanyingchart. The classificationhere used may be expressedin tabular form as follows:

ORDER PELECANIFORMES SUBOm>ER PHAtITHONTES FAMILY PHAtITHONTIDAE SuBoratoR FREGATAE FAMILY FREGATIDAE SUaOe,D•R PELECANI SOP•R•AMmY PELECANIDES FAMILY PELECANIDAE CYPHORNITHIDAE (extinct) SUPERFAMILY SULIDES FAMILYPELAGORNITHIDAE (extinct) SULIDAE ELOPTERYGIDAE (extinct) ANHINGIDAE PHALACROCORACIDAE S•Jaom•e•tODONTOPTERYGES (extinct) (of uncertainposition) FAMILY ODONTOPTERYGIDAE PSEUDODONTORNITHIDAE (of uncertainposition) 70 GROSKIlW,Coloro! Shoulders o!Male Goldfinch I.I'Auk Jan.

Acknowledgmentsare due ProfessorLoye H. Miller, who made availablefor studythe skeletalmaterial at the Universityof Cali- forniaat LosAngeles, and to Dr. AlexanderWetmore for suggestions maderegarding the advisabilityof retainingsub-ordinal rank for Phagthonand Fregata. LITERATURE CITED BEDDARD,F. E. 1898. Structureand cl•tssification of birds. 548pp. (London.) C•UES,ELLIOT 1903. Key to North Americanbirds; Fifth edition, 1152 pp. (Boston.) LAMBRECHT, KALMAN 1933. Handbuchder Palaeornithologie.1024 pp. (Berlin.) MILLER, L. H. 1925. Arian remainsfrom the Mioceneof Lompoc,California. CarnegieInst. Wash., 349: I07-I17. M•vn•r, St. G. 1878. On the axial skeleton of the Pelecanidae. Trans. Zool. Soc. London, 10: 315-378. MURPHY, R. C. 1936. Oceanicbirds of South America. 1245pp. (New York.) PKTERS,j. L. 1931. Checklist of birds of the world, 1. 345 pp. (Cambridge.) SHUFELDT, R. 1894. On the affinitiesof the Steganopodes.Proc. Zool. Soc. London: 160-162. •VETMORE, ALEXANDER 1928. The systematicposition of the fossilbird Cyphornismagnus. Bull. Canad. Geol. Survey, 49: 1-4. 1940. A systematicclassification for the birds of the world. Smiths. Misc. Coil., 99 (no. 7): 1-11. Hull ZoologicalLaboratories Universityof Chicago Chicago,Illinois

VARIATIONS IN COLOR OF THE SHOULDERS OF THE MALE GOLDFINCH

BY HORACE GROSKIN DURINGthe six-yearperiod, 1940 to 1946, I banded 1,249 Eastern Goldfinches,Spinus tristis tristis, in Ardmore,Montgomery County, Pennsylvania. Forty-twobirds (3.36%) returned to Ardmore in the followingyears. Somereturned one year after bandingand again a secondand third year, while otherswere not recaptureduntil two or three yearsafter banding. When the birds were banded, their wings were measured. The closed-wingmeasurement, or the chord,was taken of a seriesof 1,027