THE PHYLOGENY OF THE ALCIDAE

J. G. STRAUCH,JR. UniversityMuseum (Zoology), Campus Box 315, Universityof Colorado, Boulder, Colorado 80309 USA

ABSTRACT.--Anestimate of the phylogeny of 22 extant and 1 extinct speciesof the Alcidae was determinedfrom compatibilityanalyses of 33 cladisticcharacters of the skeleton,integ- ument, and natural history. The were found to be a sister-group to all other alcids. Cerorhincawas found to be a . The auklets were found to be a sister-groupto the remainingspecies. was found to representa phyleticline separatefrom that including the other murrelets. was found to be a member of the phyletic line in- cluding Endomychuraand .Alle was found to be a sister-groupof the . A compatibility analysisof musclecharacters of Hudson et al. (1969) yielded a phylogenetic tree in agreementwith that found usingmy data.The relationshipsamong Cepphus and the murrelets were found to need further study. A classificationbased on these results is sug- gested.It is recommendedthat the recent merging of genera by the A.O.U. (1982) be ac- cepted,that Cyclorrhynchusbe mergedwith ,and that Pinguinusbe mergedwith Alca. Received25 January1984, accepted 3 December1984.

THEAlcidae, a distinctgroup of marine,- evidencethat sandgrouseare charadriiforms. propelled diving , have been classified Although current evidence indicatesthat the during the past 150 (literature reviewed compositionof the Charadriiformesis closeto by Sibley and Ahlquist 1972) with the loons that proposedby Wetmore (1930), future reso- (Gaviidae), grebes(Podicipedidae), diving pe- lution of the higher relationshipsof birds may trels (Pelecanoididae),and (Sphenis- show this conclusionto be oversimplified. cidae). The modern consensusis that they are Given that the Alcidae are charadriiforms, members of the (Wetmore there is still a questionof their affinitieswithin 1930, Mayr and Areadon 1951, Kitto and Wil- the order. Most authorshave suggestedthat al- son 1966,Storer 1971,Sibley and Ahlquist 1972, cids are most closely related to (Storer Stegmann 1978, Strauch 1978, Cracraft 1981); 1960, Kozlova 1961). Ahlquist (1974) reported however, a few recent authors (Verheyen 1958, that the isoelectricfocusing in polyacrylamide Gysels and Rabaey 1964) have disputed this (IFPA) patterns of -white proteins of opinion. The assumedmonophyly of the Cha- "shows an unmistakable likeness to those of radriiformes is based on their sharing a com- gulls." Evidencethat the ancestorof the alcids plex of character states (Zusi 1974, Strauch may have been more like a shorebirdhas been 1976), but it never has been tested by a phy- reportedby Stettenheim(1959), Hudson et al. logenetic analysis of the orders of birds. Fur- (1969), and Stegmann (1978). However, be- thermore, the limits of the order still are un- cause there is considerable evidence that Dro- resolved.Storer (1956) and Sibley and Ahlquist rnasis closely related to the (Strauch 1978, (1972) presented evidence that the loons also Sibley and Ahlquist in press),a shorebird-like may be charadriiforms(but see Cracraft 1982). common ancestorof alcids and larids may not Olson and Feduccia (1980) assertedthat the fla- conflict with earlier ideas. Strauch (1978) and mingos (Phoenicopteridae)are closely related others(Stegmann 1978, Cracraft 1981)were un- to Charadriiformes, and Olson and Steadman able to identify the closestrelatives of the al- (1981) presented evidence that Pedionomusis a cids. On the basis of DNA-DNA hybridization charadriiform. Maclean (1967) and Fjeldsfi studies, Sibley and Ahlquist (in press) found (1976) argued that sandgrouse(Pteroclididae) that the Alcidae and Lari are sister-groups. are charadriiforms, but their evidence and con- The Alcidae are distinguished among cha- clusionshave been challengedby Olson (1970) radriiform birds by their compactform, short and Strauch (1979) and are not supported by , and feeding habits (Coues1868). Some the findings of Kitto and Wilson (1966). Sibley of the characteristics(sternum long and narrow and Ahlquist (in press), however, have new with long, rounded metasternum;wing bones 520 The 102: 520-539. July 1985 July1985] Phylogenyofthe Alcidae 521 flattened)used to define them (Verheyen 1958, and Aethiinae (the remaining genera). Yudin Zusi 1974) may be related to their marine and (1965) thought that there probably were two diving habits; others (large supraorbital phyletic lines in the Alcidae but found insuf- grooves, basipterygoid processesabsent in ficient grounds on which to divide them. He adults,anterior toes fully webbed,hind toe ab- suspectedthat similarities in the jaw muscula- sent) are found in other charadriiform birds. ture of puffins and auklets were due to "par- Strauch (1978) found the Alcidae to be a mono- allel development."In a study of the wing and phyletic group defined by twisting of the leg musculature,Hudson et al. (1969) found that brachial tuberosity of the coracoid so that it the puffins differed markedly from other al- doesnot roof the triossealcanal and by lack of cids, were probably the most primitive living a lateral synsacralstrut. alcids,and were closestto Ptychoramphus,among Coues (1868) used nostril feathering, bill the genera studied. They found that Brachy- form, and presenceor absenceof creststo di- ramphuswas not particularlyclose to any other vide the Alcidae into three subfamilies: Alci- ,but was closer to Uria and Alca than to nae (Pinguinus,Alca), Phaleridinae (Fratercula, Cepphus,other murrelets,auklets, or puffins;and Lunda, Cerorhinca,Ptychoramphus, Cyclorrhyn- they found Cepphusto be closestto Uria and chus,Aethia), and Urinae (Synthliboramphus,En- Synthliboramphus.Several authors (Storer 1945b, domychura,Brachyramphus, Cepphus, Alle, Uria). Sealy 1972, Binford et al. 1975, Jehl and Bond Beddard (1898) used the number of rectrices, 1975) have concluded that among the murre- relative size of the right and left liver lobes, lets Endomychuraand Synthliboramphusare quite leg muscleformula, and form of the syrinx to similar and that both are distinct from Brachy- divide the alcids into two families: Fraterculi- ramphus. dae (Cerorhinca,Lunda, Fratercula)and Uriidae It haslong been agreedthat the puffins (Cero- (all other genera). Shufeldt (1901), summariz- rhinca, Lunda, Fratercula),the auklets (Ptycho- ing a seriesof papers on the osteologyof the ramphus,Cyclorrhynchus, Aethia), and the auks alcids (1888, 1889a-d), decided that Beddard's (Uria, Alca,Pinguinus) are clustersof closelyre- two families representedtwo subfamilies.Shu- lated . The relationships among the feldt (1889d) thought Alle closestto the auklets murrelets(Brachyramphus, Endomychura, Synthli- and Uria closestto the . Dawson (1920) boramphus),the relationshipsof Cepphusand Alle usedegg characteristicssupplemented by other to other alcids,and the relationshipsamong all characters to divide the alcids into five fami- of thesegroups have been debated,however. lies: Aethiidae (Alle, Ptychoramphus,Cyclorrhyn- I reexamined the relationships among the chus,Aethia), Cepphidae (Cepphus), Alcidae (Uria, speciesof the Alcidae using a modern, objec- Alca, Pinguinus),Fraterculidae (Cerorhinca, Lun- tive method to evaluate the characters on which da, Fratercula),and Synthliboramphidae (Syn- the estimateof phylogeny is based. thliboramphus,Brachyramphus, Endomychura). Storer (1945a) usedpelvis and leg morphology MATERIALS AND METHODS supplementedby ,soft-part, egg, and I examined skins and skeletons of each living breeding characters to divide the alcids into speciesof alcid. A completecomposite skeleton and sevengroups, which he later (1960) designated severalunassociated bones of Pinguinusalso were ex- as tribes:Alcini (Uria, Alca,Pinguinus), Cepphi- amined. Integument charactersfor Pinguinuswere ob- ni (Cepphus),Brachyramphini (Brachyramphus), tained from Ridgway(1919). Natural historydata were Plautini (Alle), Aethiini (Ptychoramphus,Cyclor- taken from the literature (Storer 1945a, Kozlova 1961, rhynchus,Aethia), Synthliboramphini (Endo- Sealy 1972, Simons 1980, Terres 1980). Natural his- mychura,Synthliboramphus), and Fraterculini tory data for Pinguinuswere obtainedfrom Bengtson (Cerorhinca, Lunda, Fratercula). Storer (1952) (1984). Character names follow Howard (1929), Bock suggestedthat Alle might be closestto his A1- and McEvey (1969), Zusi and Jehl (1970), and Strauch cini and that Cepphuswas closerto the ancestral (1978). A set of 33 cladistic characters was devised for the stockof the family than was Uria. Earlier, Stor- 22 extant and ! extinct speciesstudied. Primitive states er (1945b) thought Brachyramphusthe most were determined using other charadriiform birds, primitive genusof alcid. Verheyen (1958) clas- particularly the Lari, as outgroups(Strauch 1978). sifted the Alcidae into four subfamilies: Frater- Charactercompatibility analysis employing the pro- culinae (Cerorhinca,Lunda, Fratercula), Alcinae gram CLINCH 5 (written by K. L. Fiala) was used to (Pinguinus,Alca, Uria, Cepphus),Plautinae (Alle), find the largestset of mutually compatiblecharacters 522 J.G. STRAUCH,JR. [Auk, Vol. 102

T^I•I•E 1. Character-state trees for the Alcidae.

Character-state No. Character State tree 1 Maxillopalatine strut P B • A Absent B Present A 2 Maxillopalatineshape A • B Hollow and cup-shaped A Broad, flat plate B 3 Ventral end of interpalatineprocess A • B Doesnot extendbeyond ventral end of palatine shelf A Extendsbeyond ventral end of palatine shelf B 4 Secondaryarticulation of lower jaw A • B Well developed A Absent B 5 Supraorbital rims B • A Absent B Well developed A 6 Supraoccipitalforamina A • B Absent A Present B 7 Scleroticring A • B Narrow, flat ring A Wide, conicalring with serratededge B 8 Medial sternal notch A • B Absent A Present B 9 Lateral sternal notch A • B A notch A A fenestra B 10 Sternocoracoidalprocess of sternum A • B Pointscaudally or dorsally A Points cranially B 11 Sternocoracoidalprocess of coracold A • B Well developed A Absentor poorly developed B 12 Number of sternalcostal processes A • B Six A Seven B 13 Coracoidal foramen A • B Present A Absent B 14 Hypapophysesof thoracicvertebrae A • B Well developed on all but last five vertebrae A Well developedon all but last three vertebrae B 15 Synsacralstrut A • B Well-developed strut A Absent or only a slight ridge B 16 Relativelength of ischialangle and posteriorprojection A • B of the ilium Ischial angle much longer A Both structuresabout the samelength B 17 Pneumatic fossa II of humerus A • B Well developed A Poorly developed B 18 Extensorprocess of carpometacarpus A • B Short, rounded point A Long, flat structure B July 1985] Phylogenyof the Alcidae 523

TABLE 1. Continued.

Character-state No. Character State tree

19 Tendinal canalNo. 1 of hypotarsus C • B • A Bony canal B Deep channel A Shallow groove C 20 Trochlea A • B Normal proportionsfor charadriiforms A Long and slender B 21 Claw of inner toe A • B Normal alcid shape A Stout and strongly curved B 22 Nostril feathering C • B • A Nostrils bare C Partly feathered B Feathered A 23 Head plumage A • B Typical feathering A Velvety plumage B 24 Eye scales A • B Absent A Present B 25 Incubation patches A • B Two A One B 26 Secondaries B • A Without white tips B With white tips A 27 Number of rectrices A • B • C 12 A 14 B 16 or more C 28 Shape of retrice$ A • B Rounded at tips A Pointed at tips B 29 Scutellation A • B Scutellate A Reticulate B 30 Clutch size B • A Two B One A 31 Post-hatchingdevelopment pattern A • C • B Semiprecocial C Intermediate A Precocial B 32 Nest sites C • B • A In the open C In natural crevices B In A 33 Nesting dispersion A • B Colonial A Solitary B

in the data set (for details see Estabrook et al. 1977, "depicts actual patterns of ancestry and descent Strauch 1978, Meacham 1980). This set of characters, amonga seriesof taxa"(Eldredge and Cracraft1980)], called the primary charactersor primary clique, the primary tree. It is hypothesizedthat the primary uniquely defines a phylogenetic tree [i.e. one that charactersare free from homoplasy. 524 J.G. $TRAUCH,JR. [Auk, Vol. 102

TABLE2. Characterstates for speciesof Alcidae.

Character number Species 1-5 6-10 11-15 16-20 21-25 26-30 31-33 Pinguinusimpennis B AAB A B AAAA AB AB B AB B CA AAB AB AB B AA ACA Alca torda BAAB A AAAAA AB AB B AB B CA AAB AB AAB AA ACA Uria lornvia B AAB A AAAAA ABAB B AB B CA AAB AB AAAAA ACA Uria aalge BAABA AAAAA ABABB ABBCA AABAB AAAAA ACA Alle alle BAABA BAAAA AABAB ABABA ABBAA AAAAA CBA Cepphusgrylle BAABB BAAAA AAABB ABABA ABAAA BAABB CBA Cepphuscolumba BAABB AAAAA AAABB ABABA ABAAA BBABB CBA Cepphuscarbo BAABB AAAAA AAABB ABABA ABAAA BBABB CBA Brachyramphusmarmoratus BAABB BAAAA ABBBB ABABA ABAAB BBABA CCB Brachyramphusbrevirostris B AAB B B AAAA AAB B B AB AB A AB AAB B B AB A CCB Endomychurahypoleucus B AAB B B AAAA AB AB B AB AB B AB AAA B AAB B B B A Endomychuracraveri BAABB BAAAA ABABB ABABB ABAAA BAABB BBA Synthhl•oramphusantiquus BAABB BAAAA ABABB ABABB ABAAA BBABB BBA Synthliboramphuswumizusume B AAB B B AAAA AAAB B AB AB B AB AAA B B AB B B B A Ptychoramphusaleuticus BABAB BAAAA ABBAA BBABA ABAAA BBABA CAA Cyclorrhynchuspsittacula BABAB BAABA AABAA BBABA ABAAA BBABA CBA Aethia cristatella BBBAB BAABA BABAA BBABA ABAAA BBABA CBA Aethiapusilia BBBAB BAABA BABAA BBABA ABAAA BBABA CBA Aethiapygmaea BBBAB BAABA BABAA BBABA ABAAA BBABA CBA Cerorhinca monocerata AAAAB BBBAB BBABA AAABA ACAAA BCABA CAA Fratercula arctica AAAAB AB B AB B B AB A AAAAA B CAB A B CAB A CAA Fratercula corniculata AAAAB ABBAB BBABA AAAAA BCABA BCABA CAA Lunda cirrhata AAAAB ABBAB BBABA AAAAA BCAAA BCABA CAA

A series of secondary analyses was made on se- Another compatibility analysis was made using lected phyletic branchesof the primary tree. In a some of the data of Hudson et al. (1969). They de- secondaryanalysis the compatibilityof the characters scribed 108 wing and leg musculature charactersfor that vary amongall taxaon a branch (a monophyletic the Lari and Alcidae. Of these I used 17 that varied group) is redetermined.This proceduremay find ad- among the alcids and for which the primitive state ditional charactersthat are compatiblewith the pri- could be determined from the states found in the mary characterson the branch being analyzed but Lari. In a few cases more than one state was found that are not compatibleon the primary tree. The larg- in a species;in such casesI used the state found in est clique that includesall of the primary characters the majority of the specimensexamined. The species included in the secondaryanalysis is chosenas the studied by Hudson et al. are listed in Table 4. Only set of most reliable characters. This restriction en- a primary analysiswas done on those data. suresconsistency among the primary and secondary The original data also were analyzed to find the cliques.Secondary analyses are made progressively most parsimonious tree in the data set using the from large branchesto smaller ones; the results ac- method of Colless (1980, 1983). cepted in each analysismust be consistentwith all previous, more general analyses.Thus, relationships may be more fully resolvedon smaller and smaller CHARACTERS branchesof the tree. As each branch is reanalyzed, it is replacedby the more fully resolvedbranch deter- The charactersused in this study include 21 from mined by the secondaryanalysis. the skeleton,8 from the integument, and 4 from nat- In eachsecondary analysis the character-statetrees ural history. Homologies for structural characters for primary and secondarycharacters accepted in a were determined according to similarities in struc- more generalanalysis of the branchbeing examined ture and location (Jardine 1969, Strauch 1978, El- were taken as fixed. Character-statetrees for rejected dredge and Cracraft 1980); those for natural history characterswere reevaluated using the method of characterswere determined by the role they play in Strauch (1984). Their trees were redetermined ac- the life cycleof the species. cordingto the distributionof statesin the sister-group Although comparisonwas madewith specimensof of the branch being analyzed. If the evidence from all other majorgroups of charadriiformbirds to de- the sister-groupwas ambiguous,the original form of termine primitive states,when there were ambigu- the character-state tree was used. ities because several states were found in the out- July1985] Phylogenyof the Alcidae 525

mpsP

Fig. 1. Right lateralview of the skull of Cerorhinca rnonocerata.1 = lacrimal, rnpsP= rnaxillopalatinestrut character-statetrees are given in Table 1. A table en- P, p = palatine. try of A • B rneansthat the prirnitive state is A and the derived state is B; the tree can be read as "state A is the ancestor of state B." The character states for the 23 speciesare given in Table 2. groups,greatest weight wasgiven to the statesfound Character1.--Maxillopalatine strut P (Fig. 1). The in the Lari. rnaxillopalatinestrut found in puffins does not ap- The descriptionsof the charactersand their states, pear to be hornologouswith any of those found in as well as the distribution of the statesamong the other charadriiforrns(Lowe 1931, Bock 1958, Zusi and outgroupsand in the Alcidae, are outlined below. In Jehl 1970, Strauch 1978). Its presenceis considered mostcases the statefound in the outgroupis hypoth- to be derived. esizedto be the primitive (plesiornorphic)state, while Character2.--Maxillopalatine shape(Fig. 2). In the that found only in somealcids is hypothesizedto be Charadriiforrnes,except Aethia, the rnaxillopalatineis the derived (apornorphic)state. Complex situations a hollow, cup-shapedstructure; in Aethiait is a broad, are described in more detail. The character states and flat plate that when viewed ventrally extendsalrnost to the vorner. Character3.--Ventral end of the interpalatine pro- cess(Fig. 2). The ventral end of the interpalatine pro- ipp ps cessdoes not extend as far ventrally as the ventral edge of the palatine plate in rnostcharadriiforrns. In the auklets,however, it extendsbeyond the edge of the palatine shelf. Character4.--Secondary articulation of the lower jaw. The Lari, auklets, and puffins have a well-de- J velopedsecondary articulation of the lower jaw. The articulation is absentin the rnurrelets,Cepphus, Alle, and the auks. Kozlova (1961) reported the presence of the basisphenoidprocesses associated with this ar- ticulation in alcids. Bock (1960) reported the articu-

Fig. 2. Ventral view of the palate of Aethiacris- tatella.j = jugal bar, rnp = rnaxillopalatine,ps = pal- Fig. 4. Sclerotic rings of Lunda cirrhata(A) and atine shelf, ipp = interpalatineprocess, v = vomer. Uria aalge(B). 526 J.G. STRAUCH,JR. [Auk, Vol. 102

scv Iss pU ...... : '":'•'•o '•' •'• '

Fig. 7. Lateral ventral view of the right side of A 8 the synsacrumof Uria1omvia (A) and Fraterculaarctica (B). lss = lateral sternal st•t, pu = pubis, scv = Fig. 5. Ventral view of the caudalend of the ster- sacral-caudal vertebrae. num of Aethia cristatella(A) and Cerorhincamonocerata (B). lsn = lateral sternal notch, msn = medial sternal notch. charadriiforms have a medial sternal notch, but sev- eral, includingmembers of the Lari and Alcidae,do lation absent in alcids, but did not report which taxa not. Distribution of the states among other charad- he examined. riiforms thus doesnot indicate which state is primi- Character5.--Supraorbital rims (Fig. 3). The su- tive in the alcids. Because the notch is absent in the praorbital rims are only partially developed in the Gruiformes (except the Otididae), which are proba- Lari and someof the alcids.They are fully developed bly a sister-groupof the Charadriiformes,I hypoth- in the auks. esized($trauch 1978)that absenceof the medial notch Character6.--Supraoccipital foramina. Supraoccipi- is primitive in charadriiforms.That coding is used tal foramina are absent in the skulls of adult Lari and here. mostother groupsof charadriiforms;they are present Character9.--Lateral sternal notch (Fig. 5). Almost in some speciesof alcids. Beddard (1898) reported all charadriiforms(including all Lari) have a lateral that in alcids these foramina sometimes become sternal notch. In the auklets it is reduced to a fenes- obliteratedwith age.$hufeldt (1888)found them "by tra, a condition assumed to be a derived state in the no means a constant character." Alcidae. $hufeldt (1888, 1889a) and Lucas (1890) re- Character7.--Sclerotic ring (Fig. 4). The sclerotic ported that in the auks the lateral sternal notch tends ring of mostcharadriiforms is a flattish,narrow ring. to becomeossified with age. This condition clearly That of puffins,however, is distinctly conicaland has differsfrom that in the auklets;it is hypothesizedto a serratedinner edge. $hufeldt (1889d) was the first representmerely a variant of the statewith the notch to describe this condition for the puffins. Curtis and present. Kuroda (1954, 1955) illustrates the variation Miller (1938) discussedthe variation found in the with age of the sternalnotching of somealcids. scleroticring of North Americanbirds. Character10.--Sternocoracoidal process of sternum Character 8.--Medial sternal notch (Fig. 5). Most (Fig. 6). In the Lari and most other charadriiforms the sternocoracoidalprocess of the sternum points caudallyor dorsally;in the puffins it points distinctly cranially. Character11.--Sternocoracoidal process of cora- coid. The sternocoracoidalprocess of the coracoidis well developed in the Lari and most other charadri- iforms; it is absent or poorly developed in some of the auklets.These differences are illustratedby Ku- roda (1954: Fig. 7) and are mentioned by $hufeldt (1889c). Character12.--Number of costalprocesses (Fig. 6). There are six costalprocesses on the sternumof the Lari and most other charadriiforms; some alcids have seven. A B Character 13.--Coracoidal foramen. The Lari and most other charadriiforms have a coracoidal foramen; Fig. 6. Lateral view of the cranial end of the ster- it is absentin some speciesof alcids. num of Aethia cristatella(A) and Cerorhincamonocerata Character14.--Hypapophyses of thoracic verte- (B). cp = costal process, sps = sternocoracoidalpro- brae. The Lari and other nonalcid charadriiforms have cess of sternum. poorly developed hypapophyseson their thoracic July1985] Phylogenyofthe Alcidae 527

ppil

A exmp

B Fig. 10. Ventral view of the proximal end of the carpometacarpusof Cerorhincamonocerata (A) and Uria lomvia(B). exmp = extensor processof metacarpus.

Fig. 8. Lateral view of the caudalend of the syn- sacrumof Aethiacristatella (A) and Uria lomvia(B).isa = Character16.--Relative length of the ischial angle ischial angle, ppil = posteriorprojection of ilium, and posteriorprojection of the ilium (Fig. 8). In the pu = pubis. Lari and most other charadriiformsthe ischial angle is much longer than the posterior projection of the vertebrae.Well-developed hypapophyses,most with ilium; in the auklets the length of the ischial angle is much reduced, and the structures are almost the bilateral flanged wings, are found in all alcids, but the number of vertebraeon which they occurvaries same length. These differencesalso are indicated by among the species.It is hypothesizedthat a greater Storer's (1945a) measurements of alcid skeletons. number of vertebrae with well-developed hyp- Character17.--Pneumatic fossaII of humerus (Fig. apophysesis a more derived condition. Similar struc- 9). The Lari and most other charadriiforms have a turesare found in loons,grebes, penguins, and some well-developed pneumatic fossa II of the humerus; anseriforms • Beddard 1898). in some alcids, however, it is poorly developed or Character15.--Synsacral strut (Fig. 7). In most cha- almost completely absent. radriiforms a strut or brace extends from the fused Character18.--Extensor process of carpometacarpus sacral-caudal vertebrae to the acetabulum. In the al- (Fig. 10). The extensorprocess of the carpometacar- cidsthis strut may be well developed(contra Strauch pus is a short, rounded point in the Lari and most 1978), it may be reduced to a very slight ridge, or it other charadriiforms;in someof the alcids it is long and flat. may be completely absent. Character19.--Tendinal canal No. 1 of hypotarsus. The pattern of the canals in the hypotarsus of cha- pfll radriiforms is discussedby Strauch (1978). Only the condition of the canal assumed to be for the tendon cg of M. flexor digitorum longus shows different states in the Alcidae. In most charadriiforms canal No. 1 is a bony canal; in the Lari it is either a bony canal or a deep channel. In the Alcidae it may be a bony canal (most species),a deep channel (some puffins), or a shallow groove (the auks). The bony canal in cha- radriiforms is hypothesized to be primitive (Strauch 1978).More open canalsin the hypotarsushave been linked with greater specializationand probably rep- resent derived states (Harrison 1976). A B Character 20.--Trochlea. In the Lari and most alcids Fig. 9. Ancohal view of the proximal end of the the proportionsof the trochlea are similar. In some humerus of Alca torda (A) and Lunda cirrhata (B). murreletsthe trochleaeare relatively long and some- cg = capital groove,dc = deltoid crest,pfII = pneu- what compressedand give the tarsometatarsusa slen- matic fossa II. der appearance(Storer 1945b). 528 J.G. $TRAUCH,JR. [Auk, Vol. 102

18. It is hypothesizedthat an increasingnumber of rectricesrepresents increasingly derived states. Character28.--Shape of rectrices.The rectricesof the Lari and most other charadriiforms have rounded tips. In someauks the rectricesare distinctlypointed. Character 29.--Scutellation. The scutellation on the podothecaof the Lari is scutellate.In alcids it may be either scutellateor reticulate.Coues (1868), Ridg- way (1919), and Verheyen (1958) describe several subclasses of scutellation for alcids, and sometimes disagreeabout them. A. J. Baker (pets. comm.) and I found only two major types in the specimenswe ex- amined. Character 30.--Clutch size. The Lari and almost all other charadriiformslay a clutch of two or more. Al- Fig. 11. Lateral view of the claw of the inner (sec- though some alcids lay two , most specieslay ond) toe of Lundacirrhata (A) and Alca torda(B). only one. Character31.--Post-hatching development pattern. Alcids have three distinct post-hatching develop- Character21.--Claw of the inner (second)toe (Fig. ment patterns:precocial, intermediate, and semipre- 11). The claw of most charadriiformsis moderately cocial (Sealy 1973). The pattern for Pinguinusis un- arched,compressed, and acute(Coues 1868). In puf- known. Bengtson(1984), in a review of the literature fins that dig their own burrows, the inner (second) on Pinguinus,estimated that chicks leave the nest at toe is usually stout and strongly curved. Figure 11 about 10 days old, which would agree with an inter- shows the toe with the claw attached; Shufeldt (1889d) mediate pattern. In the Lari the pattern is semipre- illustrates the ungual phalanx with the claw re- cocial;it is hypothesizedthat shortening of the nest- moved. Although it has been assumedthat this toe ling period in alcids representsa derived condition. is used in digging burrows, I could not find a de- Character32.--Nest sites.The Lari nest in the open, scription of its use. as do some alcids. Other alcids nest in crevices or in Character22.--Nostril feathering. The nostrils of burrows.Kozlova (1961) thought that the original nest the Lari, some alcids, and most other charadriiforms sitesof alcids were "on open rocks or coastalcliffs." are bare. Some alcids have partially feathered nos- It is hypothesized that nesting in crevicesor in bur- trils, and others have completely feathered ones. It rows representsincreasingly derived conditions. is hypothesizedthat increasingfeathering represents Character33.--Nesting dispersion. The Lari and progressivelyderived states. This characterwas first most of the alcids nest in colonies.Some speciesof usedby Brandt(1837) to classifythe alcids. alcids, however, nest solitarily. Character23.--Head plumage. The head plumage Charactersconsidered but rejected becausemore of the Lari and most other charadriiforms consists of than one statewas found in a specieswere the fusion typical feathers;in some alcids the head plumage is of the interorbital septum and brain case[Shufeldt distinctly velvety. (1901) reported this to vary with age], the presence Character24.--Eye scales.The Lari and most other of a mandibular fossa, the number of caudal and cer- charadriiformshave no eye scales;they are present vical vertebrae, and the diet (see B•dard 1969). ! found in somepuffins. insufficientinformation for every speciesto usecolor Character 25.--Number of incubation patches. of the eye or mouth lining, the shedding of the bill Paired lateral incubationpatches are found in shore- plates,the shapeof the first bronchial semirings,the birds,Lari, and somealcids (Bailey 1952). Some alcids size of the two lobesof the liver, the tongue or palate have only one patch. charactersof B•dard (1969), or the barring of the ju- Character26.--White-tipped secondaries.In the Lari venal plumage. I could not devise a credible char- the secondariesmay be solid-coloredor white-tipped. acter-state tree for the egg categoriesof Dawson The condition in the Lari thus does not indicate the (1920). primitive statein the Alcidae.Since dark-tipped sec- The characterdescriptions and character-statetrees ondariesare found in three of the four major groups for the data of Hudson et al. (1969) are given in Table of alcids ["widespread"according to the principles 3. The characterstates for the 12 speciesthey studied of Kluge and Farris (1969)],white tips are hypothe- are given in Table 4. sized to be a derived state. Character 27.--Number of rectrices. The Lari have RESULTS 12 rectrices.Alcid speciesmay have 12, 14, 16, or 18 rectrices.The number appearsto be constantwithin The compatibility analysis of the 33 charac- a speciesexcept for Cerorhinca,which may have 16 or ters for the 23 speciesof alcidsfound one larg- July1985] Phylogenyof theAlcidae 529

TABLE3. Character-statetrees for wing- and leg-musculaturecharacters of Hudsonet al. (1969).

Character-state No. Character State tree H1 M. pectoralisabdominalis A • B Insertion on tendon of M. pectoralisthoracica A Insertion on humerus B H2 M. subcoracoideus A • B Small or absent anterior head A Anterior head short or long B H3 M. propatagialislongus A • B Dilation at wrist unossified A Dilation at wrist ossified B H4 M. propatagialis A • B 2 tendons A 1 tendon B H5 Patagialfan sesamoid A • B Present A Absent B H6 M. deltoideus minor A • B Dorsal head present A Dorsal head absent B H7 Swellingin M. tricepstendons A • B Unossified A Ossified B H8 Swellingin humero-ulnarpulley A • B Ossified A Unossified B H9 M. bicepsbrachii C • A • B Divided lengthwise A Divided distally B Undivided C H10 M. flexordigitorum sublimis A • B Dilation at base of phalanx 1 ossified A Dilation at base of phalanx 1 unossified B H11 M. ulnimetacarpalisdorsalis A • B Ventral head present A Ventral head absent B H12 M. ambiens A • B Present A Absent B I-I13 Parsiliofemoralis of M. piriformis A • B Absent A Present B H14 Parsinterna of M. gastrocnemius A • B Extends around anterior surface of knee A Does not extend around anterior surface of knee B H15 Parsinterna of M. gastrocnemius A • B No extra head from tibia A Extra head from tibia B H16 ParsmediaIls of M. gastrocnemius A • B Present A Absent B H17 M. plantaris A • B Present A Absent B 530 J.G. STRAUCH,JR. [Auk, Vol. 102

TABI•E4. Characterstates for speciesof Alcidae; data of Hudson et al. (1969).

H character number

Species 1-5 6-10 11-15 16-17 Alca torda ABBAB BAACA ABBBB AA Uria lomvia ABAAB BAACB ABBBB AA Uria aalge AB AAB BAACB ABBBB AA Cepphusgrylle ABAAB AAB CB ABBBB AA Cepphuscolumba AB AAB AAB C B ABBBB AA Brachyramphusmarmoratus AB B AB AAACB ABBBA BB Synthliboramphusantiquus AB B B A AAACB BBBBB AA Ptychoramphusaleuticus B AB B B AAAAB BBABA AA Cerorhinca monocerata AAAAB AB AB A AAAAA AA Fratercula arctica AAAAB AB AB A AAAAA AA Fratercula corniculata AAAAB AB AB A Lunda cirrhata AAAAB AB AB A

est clique of 23 characters:1-5, 7-10, 15-24, 26, clique (Fig. 13) showsthat on the basisof char- 28, 31, 33. The tree defined by this clique is acter 30 Cepphusis a member of the phyletic shown in Fig. 12. It showsthat the earliestsplit line that includes Endomychuraand Synthlibo- in the alcid phylogenetic tree gave rise to two ramphus. branches:one leading to the puffins and one A secondaryanalysis was made of the murre- leading to the auklets, murrelets,Cepphus, Alle, lets,Cepphus, Alle, and the auks,using the auk- and the auks. The second branch divided fur- lets as an outgroup.For this analysisthe char- ther, the first split giving rise to a branch lead- acter-state trees for characters 6, 13, and 14 were ing to the auklets and one leading to the receded(Table 5). The compatibilityanalysis of murrelets, Cepphus,Alle, and the auks. Endo- the 19 charactersthat varied among the 14 mychuraand Brachyramphusare found on dif- speciesof murrelets,Cepphus, Alle, and the auks ferent phyletic lines. The relationshipsof Cep- gave a largest clique of 12 characters:5, 18-20, phusare unresolved.[The occurrenceof extant 22, 23, 26, 28-31, 33. This clique containsall of taxa on intermediate nodes does not necessar- the primary and previouslyaccepted secondary ily imply that these taxa are ancestorsof other charactersused in the analysis, but no new extant taxa, only that none of the characters characters. usedin the study distinguishesthem from their The reciprocal of the previous analysis was hypotheticalancestor. Strauch (1978) discussed made using the murrelets, Cepphus,Alle, and how to interpret the estimatesof phylogenetic the auks as the outgroup for the auklets. Char- trees developed from compatibility analysis.] acter 11 was receded (Table 5) to its original A secondaryanalysis was made of the auk- form. The compatibility analysis of the 5 char- lets, murrelets, Cepphus,Alle, and the auks. Be- acters that varied among the 5 speciesof auk- fore this analysis was made the character-state lets gave one largestclique of 5 characters:2, trees for the ten charactersrejected in the pri- 9, 11, 12, 32. This clique containsall of the char- mary analysis(6, 11-14, 25, 27, 29, 30, 32) were acters used in the analysis:the primary char- reevaluated (Strauch 1984). The reevaluatien acters2 and 9 plus the previouslyrejected char- used puffins as an outgroup. On this basisthe acters 11, 12, and 32. No new transitions were character-state trees for characters 11, 12, 14, identifiedby the tree determinedby this clique. 27, 29, 30, and 32 were revised (Table 5). A A final analysis was made of Alle and the compatibility analysisof the 26 charactersthat auks using the murrelets and Cepphusas out- varied among the 19 speciesused in this anal- groups. Character 14 was revised (Table 5) for ysisgave one largestclique of 18 characters:2- this analysis. The compatibility analysis of the 5, 9, 15, 16, 18-20, 22, 23, 26, 28-31, 33. This 12 charactersthat varied among the 5 species clique includes the 16 primary characters in- in this analysisfound two largest cliques of 10 cluded in the analysis plus 2 of the revised characterseach: (A) 12-14, 18, 19, 22, 25, 28, 31, characters(29 and 30). The tree defined by this 32; (B) 6, 12-14, 18, 19, 22, 25, 31, 32. Only clique July1985] Phylogenyofthe Alcidae 531

• Alca/ "•ng • Alca/

•Endo/•a•11e• Brac CyclAethFrat Endo/ • •11e 2 IAeth sy• d S

Fig. 12. Primary phylogenetictree of the Alcidae, Fig. 13. Secondaryphylogenetic tree of the non- defined by 23 characters. Aeth = Aethia, Brac = puffin alcids. Abbreviations as in Fig. 12. Brachyramphus,Cepp = Cepphus,Cero = Cerorhinca, Cycl = Cyclorrhynchus,Endo = Endomychura,Frat = Fratercula,Lurid = Lunda,Ping = Pinguinus,Ptyc = tree determined by this clique is shown in Fig. Ptychoramphus,Synt = Synthliboramphus. 16. This tree includes a transition not found in my data set that indicates that Cepphus,Syn- thliboramphus,Uria, and Alca share a most recent A included all of the primary and previously common ancestor not shared with Brachyram- accepted secondary characters used in this phus. analysis.Characters 12-14, 25, and 32 are new- The tree from the data of Hudson et al. (1969) ly accepted on this branch. The tree deter- is consistentwith that found from my data, as mined by this clique (Fig. 14) shows a new shown by a compatibilityanalysis using the two transition separatingAlle from the common phylogenetictrees (Figs. 15, 16) as character- ancestor it shares with the auks. state trees for the taxa common to both data The final phylogenetictree for the Alcidae sets. The two trees are compatible and deter- found from these analysesis shown in Fig. 15. mine the tree shown in Fig. 17. The analysisof the 17 wing- and leg-muscle A nonexhaustivesearch using the parsimony charactersfor 12 speciesderived from the study program of Coiless(1980, 1983) found 33 dif- of Hudson et al. (1969) gave one largest clique ferent, shortest, equal-length trees (one of of 12 characters: Hi, H2, H6-H9, H12-H17. The which was found by the Wagner-78 program).

T^•3LE5. Recodedcharacter-state trees for charactersrejected in the primary analysis,as recodedfor indi- cated secondaryanalysis.

Secondaryanalysis Character Murrelets, Cepphus, no. Nonpuffin alcids Alle, and auks Auklets Alle and auks

6 A•B B•A -- B•A 11 B•A -- A•B -- 12 B•A B•A B•A B•A 13 A•B B•A -- B•A 14 B•A A•B -- B•A 25 A•B A•B -- A•B 27 C•B•A C•B•A -- C•B•A 29 B•A B•A -- -- 30 A-B A-B -- -- 32 A•B•C A• B•C A•B•C A•B•C 532 J.G. $TRAUCH,JR. [Auk,Vol. 102

Pi• Alca/ Al•a/ g g Aeth Alle Uri•;e/ Fig. 14. Secondary phylogenetic tree of Alle and Endo/BraC•Lun Frat the auks. Abbreviations as in Fig. 12. Cero

I estimate that there are at least 45 trees of this length if only dichotomies are allowed. These trees had several features in common. The ear- Fig. 15. Final phylogenetic tree of the Alcidae. Abbreviations as in Fig. 12. liest split in the alcid tree was the same as de- termined by the compatibility analyses, and showed the same relationships among the lated to the auks. On the other hand, the phy- speciesof puffins as determined by the com- logeny found here differs substantially from patibility analyses;they place AIIe and the auks Storer's(1960), although it agreesin the com- on the same branch, but they indicate three position of someof his phyletic lines. different setsof relationshipsamong the auks; These results show that the earliest split in they place the auklets on the same branch and the alcid phylogenetic tree gave rise to two show the same relationships among them as phyletic lines: one leading to the puffins and found in the compatibility analyses;and they one leading to the auklets, murrelets, Cepphus, show Endomychuraand SynthIiboramphusto be AIle, and the auks. The puffins are defined by closely related. As for the relationships among the presence of maxillopalatine strut P (char- Cepphus,the murrelets, and the auklets, how- acter 1); a wide, conical sclerotic ring with a ever, the trees show 15 different patterns, some serratedinner edge (7); medial sternal notches of which place the speciesof Cepphuson dif- (8); and cranially pointing sternocoracoidal ferent phyletic lines. processesof the sternum (10). Lunda and Fra- tercuIaare further defined by tendinal canalNo. DISCUSSION 1 of the hypotarsus,a deep channel (19); and a

PHYLOGENY stout, strongly curved inner toe (21). FratercuIa is defined by the presence of eye scales (24). My earlier finding (Strauch 1978) that the A1- cidae are defined by a twisted brachial tuber- osity of the coracoldis supportedby this study; Uria/ -- that they alsoare defined by lack of a synsacral strut is not, because the strut is found in the • Cepp puffins and auklets. Additionally, I found that alcidsare also defined by the presenceof well- developed hypapophyseson the thoracic ver- tebrae (character 14). The phylogenetic tree obtained in this study supportsmany previously held ideas about the relationshipsamong the alcids:that the puffins Frat are a monophyletic group that includes Cero- rhinca; that the auklets are a monophyletic group; that Brachyramphusand Endomychuraare Fig. 16. Primary phylogenetic tree from the data not closely related; and that AIIe is closely re- of Hudson et al. (1969). Abbreviationsas in Fig. 12. July1985] Phylogenyof the Alcidae 533

These are all statesof primary characters,and all but one are skeletal characters. Various authorshave suggestedthat the puf- fins are either the most primitive or the most advancedalcids. That they are the only living representatives of one of the branches of the Brac earliest split in the alcid phylogenetic tree, however, does not indicate that they are nec- essarilyprimitive. The idea that they are ad- Cepp c vanced arisesfrom a tendency to think of the most numerous and familiar group of species in a family as somehowrepresenting the gen- Frat eralized and primitive condition from which smaller distinct groups have been derived. Among the alcids, the auks, Cepphus,and the murrelets have long been the norm against Fig. 17. Phylogenetic tree resulting from combin- which the other membershave been judged. ing the results of this study and that of Hudson et Although the puffinsare indeed quite different al. (1969). Abbreviations as in Fig. 12. from the auks, their differences combine the retention of primitive statesabsent in the auks with the possessionof derived statesnot found The murrelets, Cepphus,Alle, and the auks are in other alcids. Representativesof all the alcid defined by a lack of the secondaryarticulation phyletic lines found here are known from the of the lower jaw (4) and loss of a well-devel- Upper (Olson 1985); the earlier rec- oped synsacral strut (15), states of primary ord is too fragmentary to indicate when these characters.This line splits into branches (Fig. lines first appeared.There is thus no evidence 15) leading to Brachyrarnphus,defined by soli- for designating any group of alcids as primi- tary nesting (33); to Cepphus,Endornychura, and tive. In any case,modern puffins and modern Synthliborarnphus,defined by a two-egg clutch auks are both modern representativesof phy- (30); and to Alle and the auks,defined by well- letic lines that have been evolving for ten mil- developedsupraorbital rims (5), velvety head lion years. plumage (23), white-tipped secondaries(26), The phyletic line that leads to the auklets, and a scutellatetarsus (29). The line leading to murrelets, Cepphus,Alle, and the auks is defined Brachyrarnphusand that leading to Alle and the by a poorly developedpneumatic fossa II of the auksare defined by primary characters;the line humerus(17) and partly featherednostrils (22), leading to Cepphus,Endornychura, and Synthli- both statesof primary characters.This line fur- borarnphusis defined by a secondarycharacter. ther splits into one line leading to the auklets Most of the lineages identified are defined and one leading to the remaining taxa. The by primary characters.Of the three lines found aukletsare defined by the extensionof the ven- in the group consistingof the murrelets, Cep- tral end of the interpalatineprocess beyond the phus,Alle, and the auks, however, only one is ventral end of the palatine shelf (3) and nearly defined by a primary skeletal character; the equal lengthsof the ischialangie and posterior other two are defined by natural-history char- projectionsof the ilium (16). Cyclorrhynchusand acters,only one of which is a primary charac- Aethiaare further defined by the reduction of ter. This testifies to the structural similarities of the lateral sternal notch to a fenestra (9), six these birds. costal processeson the sternum (12), and nest- The final phylogenetictree (Fig. 15) supports ing in natural crevices(32). Aethiais definedby the findings of several authors (Storer 1945b, broad, flat, platelike maxillopalatines (2) and Sealy 1972, Binford et al. 1975, Jehl and Bond an absentor poorly developedsternocoracoidal 1975) that Endornychuraand Brachyrarnphusare processof the coracoid(11). All of thesegroups not closely related and further shows them to are defined by states of primary characters, be members of different phyletic lines. Endo- supplementedby thoseof secondarycharacters rnychuraand Synthliborarnphusare defined by for Cyclorrhynchusand Aethia. long,slender trochleae (20) and a precocialpost- 534 J.G. $TRAUCH,JR. [Auk,Vol. 102 hatching development pattern (31), both states me the evidence is not irreconcilable with of primary characters.Perhaps most interesting the phylogenetic tree presented here. The fos- is the finding that Cepphusis not closelyrelated sil evidence is consistentwith a Pacific origin to the auks, but rather is a member of one of and early radiation of the Alcidae (Olson 1985). the murrelet lines. Cepphusis placed with En- Conceivably,an Alca-like ancestorentered the domychuraand Synthliboramphusbecause it shares Atlantic much earlier than Uria, but only after a two-egg clutch, a state of a secondary char- the lineagesleading to the two generahad split. acter. This is the only major transition on the The phylogenetic tree (Fig. 16) derived from phylogenetic tree defined only by a secondary the data of Hudson et al. (1969) supportsthe character. However, this character (30) shows one derived from my data. The first split in the no homoplasy on the alcid phylogenetic tree. alcid tree gives rise to a branch leading to the It is a clear example that using outgroups can puffins that is defined by an ossifiedswelling lead to errors in the estimation of primitive in the M. triceps tendons (H7) and a distal di- states(Meacham 1984,Strauch 1984). Although vision of M. bicepsbrachii (H9), and one to the a clutch size greater than one may be primitive other alcids that is defined by the absenceof for the Charadriiformes, it appearsthat a clutch M. ambiens(H12) and no extensionof M. gas- of one is primitive for alcids. If the secondary trocnemius around the anterior surface of the coding had been used in the primary analysis, knee (H14). The second branch splits further character30 would have been compatible with into one leading to the auklets that is defined all of the primary characters.The same argu- by insertion of M. pectoralis abdominalis on ment applies to character29 (scutellation). the humerus (H1), and one leading to the The ventral feathers of the juvenal plumage murrelets,Cepphus, and the auks that is defined of Cepphusand Brachyramphushave dark tips by the presenceof a head of M. subcoracoideus that give the plumage a distinct barred appear- (H2), an undivided M. biceps brachii (H9), the ance (Ridgway 1919, Kozlova 1961). Similar presenceof Pars medialis of M. gastrocnemius dark-tipped feathersrecently have been found (H16), and the absenceof M. plantaris (H17). on the flanks of juvenile specimens of The branch leading to Synthliboramphus,Cep- Synthliboramphusantiquus and Endomychurahy- phus,and the auks is defined by an extra head poleucus(Storer in litt0. The phylogenetic sig- from the tibia for Parsinterna of M. gastrocne- nificance of this character state cannot be eval- mius (H15). Finally, the branch leading to Cep- uated until the juvenal plumagesof all alcids phusis defined by an unossifiedswelling in the are better known. humero-ulnar pulley (H8), and that leading to The line leading to Alle and the auks splits the auks is defined by the lack of a dorsal head into one branch leading to Alle, defined by six of M. deltoideus minor (H6). costalprocesses (12) and by hypapophyseson The tree from the data of Hudson et al. (1969) all but the last five thoracic vertebrae (14; both indicatesthat the auks, Cepphus,and Synthlibo- statesof secondarycharacters), and one leading ramphusshare a most recent common ancestor to the auks,defined by presenceof a coracoidal not sharedwith Brachyramphus.This result sug- foramen (13), a long, flat extensor processof gestsa resolution to the trichotomy found on the carpometacarpus(18), tendinal canal No. 1 my tree. The phylogenetic trees (Figs. 15, 16) a shallow groove (19), completely feathered producedfrom independent data setsare in full nostrils (22), one incubation patch (25), an in- agreement, each showing different details of termediate post-hatchingdevelopment pattern the phylogeny of the Alcidae. (31), and nesting in the open (32). Alca and In this study 76% of the skeletal characters, Pinguinusare further defined by pointed rec- 62% of the integument characters,and 50% of trices (28). This result supports a closer rela- the natural-history characterswere included in tionship of Alle to the auks than to the auklets. the primary clique. In the analysisof the mus- Olson (1985) notes the curious absence of cle characters (Hudson et al. 1969), 71% of the of Uria in Atlantic deposits before the characterswere included in the primary clique. ,in spite of the presenceof abun- This result supports the idea that structural dant fossils of Alca-like auks in the charactersare better indicators of relationships and perhaps related birds from Middle Mio- than those of the integument or natural histo- cenedeposits. He suggeststhat this is evidence ry. However, if characters29 and 30 had been that Uria may not be closelyrelated to Alca. To used in what I believe is their correct form in July1985] Phylogenyof theAlcidae 535

the primary analysis, 75% of the integument relationship.The strength of the hypothesisof and 75%of the natural-historycharacters would relationshipsuggested by a characterthus is have been acceptedin the primary clique.Thus, basednot on an a priori belief that some char- the percentage of charactersaccepted fails to acters are better than others, but rather on how indicate that a particular type of characteris a well it agrees with the hypothesessuggested better estimatorof relationship. There are fur- by other characters. ther considerations, however. One of the 33 trees found in the parsimony I usedfewer charactersof the integumentand analysis was similar to the results of the com- natural history than of the skeleton.It was more patibility analyses, but there is no objective difficult to identify distinct characterstates for, methodto chooseit asa better tree than any of and to form logical character-statetrees from, the others.The parsimony trees use characters integument and natural-history charactersthan 6 and 27, which were rejectedin all of the com- it was for skeletal characters.For example, al- patibility analyses in which they were tested. cids have at least seven distinct bill types, but Other than agreeing that the earliest split in I could not arrange them in a credible evolu- the alcid tree givesa branchleading to the puf- tionary sequence.Coues (1868) used bill form fins and that Alle is close to the auks, the results to classifythe alcids,but his classificationagrees of the parsimonyanalysis offer little insight into poorly with the phylogeny found here. the phylogenetic relationships among the al- Another problem is variation of character cids. statesin a species.Although I eliminated from The resultsof this studyplace the phylogeny consideration skeletal characters in which more of the Alcidae on a firm empirical base. The than one state was found in a species,several major problem remaining is to resolve the re- of the muscle characters of Hudson et al. (1969) lationships among the murrelets and Cepphus. were used even though they reported some Expansionof the work of Hudson et al. (1969) variation within a species. Furthermore, for to other specieswould allow muscle characters natural-history charactersthe state character- to be included in a larger compatibilityanaly- istic of a specieswas used even though varia- sis.Unfortunately, there appearsto be no spec- tion is known. Cepphusis a particularly frus- imen of Pinguinusto include in such a study trating genus in this regard. usually (Hahn 1963). New characters must be identi- lay two-egg clutches,but one-egg clutchesare fied to test the relationshipsfound here. A bio- found regularly in all populationsstudied and chemicalstudy that estimatedgenetic distances may representup to 9% of the clutchesin some among the specieswould be particularly inter- populations(Drent 1965).One-egg clutches may esting. come from young birds breeding for the first time or older individuals entering senescence, or they may represent an environmental ad- CLASSIFICATION aptation. There is no evidence favoring any of these alternatives, however. In addition, Cep- Critics of compatibilityanalysis (e.g. Wiley phusoccasionally uses nest sites as diverse as 1981) have confusedthe processof deriving a thoserepresented in the entire family (Cramp phylogenetictree and the processof deriving et al. 1974), and on the Pacific Northwest a classificationfrom it. Compatibility analysis of it sometimesdigs burrows is an objectivemethod for deriving phyloge- (Dawson and Bowies 1909, Thoresen and Booth netic trees from sets of character-state trees and 1958, Drent 1965). Many of the colonial species not a method of classification. occasionallynest solitarily. The derivation of classifications has been These observationssuggest that integument highly controversial. Though some have as- and natural-historycharacters are more plastic serted that a classification is an information re- than those of bones and musclesand may be trieval system that somehow gives the reader more difficult to identify and use. The results considerable information on the attributes of from the compatibilityanalyses, however, show the taxa listed, the reader needs a firm knowl- that some integument and natural-history edge of the biology and structure of the taxa if characters are better than some skeletal char- a classificationis to impart much information. acters.To reject them becauseof their variabil- Furthermore,different phylogenetic trees may ity may result in ignoring good indicators of have the same classification. 536 J.G.$TRAUCH, JR. [Auk,Vol. 102

2

32

22

Fig.18. Cladogramof theAlcidae. Horizontal bars represent the characters defining the various branches, numbersrepresent characters, solid bars represent primary characters, and halftone bars represent secondary characters.Abbreviations as in Fig. 12.

The derivation of phylogenetic relation- for a family as small as the Alcidae.I prefer to ships,in spite of the uncertaintiesand difficul- use the phyleticsequencing scheme (Eldredge ties,is the biologicallyinteresting problem: and Cracraft1980), in which taxain a sequence are assignedthe samerank. The apparent tri- For, it goeswithout saying,the taxonomist'stask chotomyinvolving the murrelets,Cepphus, Alle, is to reconstructthe courseof biologicalhistory. He and the auks probably representstwo unre- is seekingnot alone a formally ordered,or traditional solveddichotomies, as suggestedin the analy- bodyof knowledge,but an understandingof the ac- sis of the data of Hudson et al. (1969). Until tual facts.If he is honest,he is not constructingsome ideal filing system;but he is reconstructingthe out- their relationshipsare better resolved! prefer line of the treeof life. He is tryingto discoverphy- to recognizethe three branchesas three equiv- logeneticrelationships .... (Dawson 1920). alent taxa of the rank given the puffins and auklets.The cladogramin Fig. 18 thussupports Figure 18 is a cladogramderived from the the classification shown in Table 6. phylogenetictree (Fig. 15) on which are indi- The A.O.U. (1982, 1983) does not indicate cated the characters used to define the various what phylogenetichypothesis forms the basis groups. A cladogram is a convenient tree (Hen- of its classification[a situationthat prevailsin dy and Penny 1984)from which to developa spite of Storer's (1945b) complaint that the classification. It tends to overstate the evi- A.O.U. Check-list Committee combined Endo- dence,however. For example,Endornychura and rnychuraand Brachyrarnphuswithout supporting Synthliboramphusappear as distinct in Fig. 18, evidence]. The A.O.U. (1983) rules for the se- but there is no evidencein this studyto sepa- quence of genera and speciesindicate that it rate them and they appear on the same node is not basedon the phylogenetic tree of Storer in the phylogenetic trees. (1960). If the A.O.U. rules are followed, its clas- The Alcidaemay be classifiedusing the sub- sificationagrees generally with that found here. ordination schemeof Hennig (1966), in which The main disagreementconcerns the details of each sister-groupis assignedthe same taxo- the arrangementof Cepphusand the murrelets. nomic rank; however, that systemrequires far The A.O.U. sequence rules, however, are at too many categoricalranks to be practical,even variance with those more generally followed July1985] Phylogenyofthe Alcidae 537

TABLE 6. A classification of the Alcidae. be kept separate,but becausethere are fossil intermediates (Olson 1985) and becauseI found Family Alcidae no qualitativedifferences between them, I dis- Tribe Fraterculini agree. Cerorhinca monocerata. Fratercula arctica. Fratercula corniculata. ACKNOWLEDGMENTS Fratercula cirrhata. I thank Robert W. Storer for encouragement Tribe Aethiini throughoutthe study and for examinationof speci- Ptychoramphusaleuticus. Cassin's Auklet mens. Ned K. Johnson, Museum of Vertebrate Zool- Aethiapsittacula. ogy, University of ; Amadeo M. Rea, San Aethiapusilla. Aethiapygmaea. Diego Natural History Museum; Robert W. Storer, Aethia cristatella. Museum of Zoology, University of Michigan; and Richard L. Zusi, National Museum of Natural His- Tribe Brachyramphini tory, kindly loaned specimensunder their care for Brachyramphusbrevirostris. Kittlitz's Murrelet use in this study. Kent L. Fiala, StorrsL. Olson, Rob- Brachyramphusmarmoratus. ert J. Raikow, SpencerG. Sealy,and Robert W. Storer Tribe Cepphini commented on earlier versions of the manuscript. Cepphusgrylle. Black Kent L. Fiala generouslyprovided computer pro- Cepphuscolumba. gramsand adviceon computation.Gene Hart did the Cepphuscarbo. parsimonyanalysis. I thank DouglasJ. Forsell for col- Synthliboramphushypoleucus. Xantus' Murrelet lecting specimensspecifically for this study in spite Synthliboramphuscraveri. Craveri's Murrelet of difficult field conditions.Allan J. Baker and Steven Synthliboramphusantiquus. M. Goodmanchecked specimens for me, and John T. Synthliboramphuswumizusume. Vollertsenkindly let me readhis manuscripton alcid Tribe Alcini phylogeny. The University Museum, University of Alle alle. Dovekie Colorado,provided computerfunds. Peter Robinson Uria aalge. and Shi-Kuei Wu extended many courtesiesto me Uria lomvia. Thick-billed Murre Alca torda. during the courseof the study.Betsy Strauch provid- Alca impennis. ed necessarycriticism and support throughout the writing and productionof the manuscript.

LITERATURE CITED (Eldredge and Cracraft 1980, Wiley 1981); the latter indicate a reversed order of the A.O.U. AHLQUIST,J.E. 1974. The relationshipsof the shore- tribes. birds (Charadriiformes). Unpublished Ph.D. dis- A genus has been defined (Mayr 1969) as a sertation, New Haven, Connecticut, Yale Univ. monophyleticgroup of speciesseparated from AMERICANORNITHOLOGISTS' UNION. 1982. Thirty- other genera by a decided gap. The problem fourth supplement to the American Ornitholo- lies in how to estimate the gap. Voous (1975) gists'Union check-listof North American birds. Auk 99: 1CC-16CC. briefly discussesthe rather loosesystem of gen- 1983. Check-list of North American birds, era traditionally used in ornithology. Even if 6th ed. Baltimore, Amer. Ornithol. Union. the rules for naming taxa suggestedby El- BAILEY,R. E. 1952. The incubation patch of passer- dredge and Cracraft (1980) are followed, there ine birds. Condor 54: 121-136. is room for subjective evaluation on the limits Bf•DARD,J. 1969. Adaptive radiation in Alcidae. Ibis of genera. BecauseI favor genera that empha- 111: 189-198. size the phylogenetic relationshipsof species, BEDDARD,F.E. 1898. The structure and classification I would reduce the number of genera recog- of birds. London, Longroans,Green. nized in the Alcidae to about six; however, a BENGTSON,$.-A. 1984. Breeding and extinc- more conservativeapproach may be necessary tion of the Greak Auk (Pinguinusimpennis): an- to promote the acceptanceof new ideas(A.O.U. ecdotalevidence and conjectures.Auk 101: 1-12. BINFORD,L. C., B. G. ELLIOTT,& $. W. SINGER. 1975. 1983). I accept the merging of genera recom- Discovery of a nest and downy young of the mended by the A.O.U. (1982) and recommend Marbled Murrelet. Wilson Bull. 87: 303-319. the following additional combinations:Cyclor- BOCK,W. J. 1958. A generic review of the rhynchusinto Aethiaand Pinguinusinto Alca. Ol- (Charadriinae,Aves). Bull. Mus. Comp. Zool. 118: son (1977) arguesthat Pinguinusand Alca should 27-97. 538 J.G. STRAUCH,JR. [Auk,Vol. 102

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