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Home , Aphelocoma, Corvidae, Cyanocitta, Florida scrub jay, Island scrub jay, Mexican jay

THE CONDOR A JOURNAL OF AVIAN BIOLOGY

Volume 98 Number 4 November 1996

.L The Condor 98~575-680 * +A. 0 The Cooper Omithological Society 1996 g ’ b.1 ;,. ’ ’ “I\), / *rs‘ A SCRUB- SUPPORTS A”kECENT ’ js.< SYSTEMATIC DECISION’ . :. ” , ., f .. . STEVEN D. EMSLIE : +, “, ., ! ’ Department of Sciences,Western State College,Gunnison, CO 81231, ._ e-mail: [email protected]

Abstract. Nine fossil premaxillae and mandibles of the Scrub-Jay( coerulescens)are reported from a late sinkhole deposit at Inglis 1A, Citrus County, Florida. Vertebrate biochronologyplaces the site within the latestPliocene (2.0 to 1.6 million yearsago, Ma) and more specificallyat 2.0 l-l .87 Ma. The fossilsare similar in morphology to living -Jaysin showing a relatively shorter and broader bill compared to western ,a presumed derived characterfor the Florida species.The recent elevation of the Florida Scrub-Jayto speciesrank is supported by these by documenting the antiquity of the speciesand its distinct bill morphology in Florida. Key words: Florida; Scrub-Jay;fossil; late Pliocene.

INTRODUCTION represent the earliest fossil occurrenceof the ge- nus Aphelocomaand provide additional support Recently, the Florida Scrub-Jay (Aphelocoma for the recognition ofA. coerulescensas a distinct, coerulescens) has been elevated to speciesrank endemic specieswith a long fossil history in Flor- with the Island Scrub-Jay(A. insularis) from Santa ida. This record also supports the hypothesis of Cruz Island, , and the Western Scrub- Pitelka (195 1) that living speciesof Aphefocoma Jay (A. californica) in the western U. S. and Mex- arose in the Pliocene. ico (AOU 1995). This designation for the Florida speciesis supported by genetic studies (Peterson METHODS 1992) and morphological and behavioral differ- ences(Pitelka 195 1, Woolfenden and Fitzpatrick Comparative measurements of modem scrub- 1984). Such a designation is not new as the Flor- jays were obtained from skeletal specimens at ida Scrub-Jay was first describedas a full species the Florida Museum of Natural History (CorvusfloridanusBartram 179 1 replaced by C. (FLMNH), Gainesville; National Museum of coerulescensBose 1793, and was only regarded Natural History (USNM), Smithsonian Institu- as conspecific with scrub-jays in western North tion, Washington, DC; Museum of Zoology, America as late as 1934 (see Pitelka 195 1 for a University of Michigan, Ann Arbor; Museum of taxonomic history of this species). Northern , Flagstaff; and Southwestern Until now, the fossil record for the Florida Museum of Biology, University of New , Scrub-Jay was limited to complete and incom- Albuquerque. All measurementswere taken with plete postcranial elements from three late Pleis- digital calipers to the nearest 0.1 mm. Measure- tocenelocalities in Florida (Fig. 1; Brodkorb 1959, ments of the premaxilla (without rhamphotheca) Hamon 1964, Ligon 1965). Here I report nine included length from anterior edge of nares to fossil specimensidentifiable to this speciesfrom tip of bill, breadth and depth taken at anterior the late Pliocene (early Irvingtonian, 2.0-l .6 mil- edge of nares, breadth of nasal bar at anterior lion years ago, Ma) of Florida. These specimens end, length of mandibular symphysis,and breadth of mandibular symphysisat posterior edge.Ratio of premaxilla 1ength:breadthwas calculated us- ’ ’ Received4 June 1996. Accepted 27 July 1996. ing the mean measurements for each species.All

[6751 676 STEVEN D. EMSLIE

HAILE QUARRIES AREWDONDQ

. LATE

A LATE PLIOCENE

FIGURE 1. Map of Florida showing the locations of the late Pliocene Inglis 1A deposit, Citrus County, and three late Pleistocenelocalities (Haile 1IB, Arredondo, Alachua County; Reddick, Marion County) where fossils of Florida Scrub-Jay(Aphelocoma coerulescens) have been recovered.

fossil specimensare housed in the collections at distal mandibular symphyses,UF 3 145 1,3 1460- FLMNH and are cataloged with University of 31461, 31468, 31472. Florida (UF) numbers. Locality and age. Inglis IA Local Fauna, Cit- rus County, Florida. This site formed from de- SYSTEMATIC PALEONTOLOGY position in a limestone sinkhole and is dated to the late Pliocene (earliest Irvingtonian, 2.0-1.6 Order Passeriformes Ma) based on mammalian biochronology (see Family Morgan and Hulbert 1995 for a review of the Aphelocoma coerulescens (Bose 1795) paleontology and age of this site). More specifi- Referred material. Two premaxillae, UF 3 1436, cally, the vertebratebiochronology correlates with 3 1449 (Fig. 2B, C); proximal right mandible, UF marine oxygen isotope stage40, dated at 2.0 1 to 3 1483; proximal left mandible, UF 3 1486; five 1.8 7 Ma, or when a glacial interval would have FOSSIL SCRUB-JAY 677

- A

I t - _ 7

I B - C

FIGURE 2. (A) dorsal view of premaxillae of male scrub-jaysshowing variation in bill morphology. Specimens are, left to right, Aphelocomacalifornica (USNM 6 11084, Nevada, woodhouseiigroup), A. califonica (USNh4 556687, California, calijbrnica group), and A. coerulescens(USNM 489957, Florida). Note the relatively longer and narrower bill in both specimensof A. californicacompared to the shorter more robust bill in A. coerulescens. Also note that the lateral margin of the bill in A. coerulescenshas a slight concavity at the midpoint compared to the straight margins in A. cahfirnica. Scale I x, bar = 1 cm. (B and C) lateral and dorsal view of male A. coerufescens(USNM 489957, top and left, respectively) with UF 31449 from Inglis 1A (bottom and right, respectively). Note the slight concavity on the lateral margin of the fossil specimen in (C) that is characteristic of A. coerulescens.Scale 1.5 x , bar = 1 cm.

causeda sea level lower than today’s (see paleo- of the premaxilla form a straight edge from the ecologybelow; Webb 1990, Morgan and Hulbert base to the tip of the bill in A. californica; in A. 1995). coerulescens and UF 31449 a slight concavity Description. The fossil material shares char- exists at the midpoint of this margin caused by acters of the living Florida Scrub-Jay as com- a relatively broader base to the bill (Fig. 2A, C). pared to western speciesofdphelocoma. The pre- The base of the premaxilla is missing in UF maxillae (UF 3 1436 and 3 1439) are relatively 3 1436. The premaxillae of the (A. short and broad, as in A. coerulescens (Table 1, ultramarina) and the (A. unicol- Fig. 2A) unlike the distinctly longer and narrower or) are relatively longer than in A. coerulescens; premaxillae in A. californica (californica and A. unicofor also has a broader bill and more ro- woodhouseiigroups, AOU 1983). No specimens bust nasal bar than A. coerulescens(see mea- from the sumichrasti group were available for surements in Pitelka 195 1). Although UF 3 1449 comparison, but measurementsfrom skins in Pi- measures slightly smaller than modem A. coe- telka (195 1: 209) indicate that scrub-jays in this rulescens, its close similarity in characters and group also have a longer and narrower bill com- proportions (ratio premaxilla length:breadth, pared to A. coerulescens.In addition, the margins Table 1) compared to other scrub-jays allows 678 STEVEN D. EMSLIE

TABLE 1. Comparative measurements(mm) giving Mean 4 SD and range (in parentheses)ofjay premaxillae without rhamphothecaecompared to fossil specimensfrom Inglis 1A. Measurementsdescribed in text.

Species LenBth Breadth -Pe Breadth nasal bar Ratio LB Cyanocittacristata (n = 11 females) 14.2 + 0.9 8.6 k 0.5 4.4 + 0.2 2.9 + 0.3 1.66 (12.8-15.9) (7.4-9.5) (4.14.7) (2.5-3.3) Aphelocomacalifornica (woodhouseii group) (n = 13 females) 14.5 * 0.7 7.1 * 0.5 4.1 + 0.4 2.4 + 0.3 2.05 (13.0-15.5) (6.2-8.2) (3.6-5.4) (2.0-2.9) (n = 11 males) 15.7 + 0.9 7.4 * 0.4 4.3 + 0.3 2.4 + 0.3 2.11 (14.1-17.1) (6.8-7.9) (3.9-4.8) (2.1-3.2) Aphelocomacalifornica (calijbrnica group) (n = 7 females) 13.6 + 0.7 7.1 k 0.3 4.1 + 0.1 2.2 + 0.2 1.91 (12.6-14.7) (6.8-7.5) (4.0-4.2) (2.0-2.6) (n = 8 males) 15.0 + 0.8 7.7 + 0.5 4.4 + 0.3 2.4 + 0.1 1.96 (14.0-16.0) (6.6-8.3) (3.9-4.8) (2.2-2.6) Aphelocomacoerulescens (n = 14 females) 13.8 f 0.7 7.9 k 0.3 4.2 + 0.2 2.6 +- 0.2 1.75 (12.4-14.7) (7.4-8.6) (3.9-4.6) (2.3-2.9) (n = 15 males) 14.3 + 0.9 8.0 + 0.5 4.3 zk0.2 2.6 + 0.3 1.78 (12.7-15.6) (7.2-9.1) (4.0-4.7) (2.2-3.2) INGLIS 1A UF 31449 11.8 6.7 4.3 3.3 1.76 UF 31436 12.7 - - -

referral to this species.The fossil mandibles are not shared with any other speciesin this too fragmentary for comparative measurements, and suggeststhat it is a derived morphology (Pi- but they also compare well in relative size and telka 195 1, pers. comm.). proportions to A. coerulescens. The paleoecologyof the Inglis 1A site indicates The fossil material also was compared to fe- a not unlike that preferred by the living males of the ( cristata), which species.The Florida Scrub-Jay is restrictedtoday approach the size of male Aphelocoma coerules- to -palmetto or sand -scrub in tens. However, measurements of the premaxilla coastal regions or on ridges in central peninsular indicate that C. cristata has a relatively longer Florida (Woolfenden and Fitzpatrick 1990, Pe- and broader bill and a more robust nasal bar than terson and Vargas-Barajas 1993). The herpeto- in A. coerulescens(Table 1). The ratio of pre- fauna from Inglis 1A suggeststhat a longleaf pine maxilla 1ength:breadthalso is smaller in C. cris- (Pinuspalustris) and xeric hammock existed near tata compared to A. californica, A. coerulescens the site during deposition; the abundance of and UF 31449. pocket gophers (Geomys sp.) also suggeststhat Discussion.These specimensrepresent the ear- the site was a “dune-like sandy terrain well above liest fossil occurrenceof this speciesand indicate the water table” (Meylan 1982: 67). The avifauna that the distinct bill morphology of Aphelocoma from Inglis 1A is diverse with over 50 taxa rep- coerulescensdeveloped by approximately 2.0 Ma. resented that reflect both upland habitats and It is not known whether or not this morphology coastal wetlands. The most abundant remains of is primitive or derived for this species. Com- are those of Northern Bobwhite Quail (Col- parable fossil material of similar age for western inus virginianus) and an extinct turkey (Mele- species is lacking. Although an analysis of bill agris leopoldior M. anza) (Steadman 1980, Carr shape with diet by Peterson (1993) suggeststhat 1981). In addition, the avifauna includes nu- the hooked bill of the Florida Scrub-Jay may be merous speciesof herons, egrets, waterfowl, ea- a primitive character, the unusually broad base gles,vultures, and owls including Burrowing Owl of the premaxilla relative to length (Table 1) is (Speotyto cunicularia) and two extinct Pygmy- FOSSIL SCRUB-JAY 679 owls (Gluucidium spp.) (Cat-r 198 1, Emslie, un- regions, but occurs in suitable habitat from publ. data). Other passerinesin the site include southern Arizona and and as far south as Seaside Sparrow (Ammodramus maritimus), Tierra de1Fuego (AOU 198 3); it occurred as far Eastern Meadowlark (Sturnellu magna), and north as Wyoming in the late Pleistocene(Emslie Brown-headed Cowbird (Molothrus ater) (Em- 1985). slie, unpubl. data). All these taxa suggestthat the The Florida Scrub-Jay, due to its restricted site was located more inland than at present, on habitat preferences,currently feeds on as drier soils above a karst substrateand with coast- its most important plant food, while western spe- al wetlands to the west, during deposition in the cies are more catholic in their habitat and diet late Pliocene. Sinkholes in the region at that time (Woolfenden and Fitzpatrick 1990, Petersonand may have held permanent or seasonalwater that Vargas-Barajas 1993). Its restriction to a habitat would have attracted various aquatic vertebrates of oak and pine-scrub habitat may explain why (Meylan 1982). the Florida Scrub-Jay survived in Florida while other avian taxa with southern and western or- CONCLUSIONS igins became extinct or extirpated there (e.g., This fossil material probably was deposited at California Condor Gymnogyps californianus, approximately the time that scrub-jays first col- Merriam’s Teratom Teratornis merriami, Great onized Florida. The vertebrate record indicates Black Hawk Buteogallus urubitinga, an extinct that numerous speciesof , birds, rep- Caracara Milvago readei, Northern Jacana Ja- tiles and other taxa first appear in Florida during cana spinosa,and Black-billed pica; the late Pliocene, probably in relation to lower Emslie, unpubl. data). As sea levels fluctuated sea levels at 2.5 Ma that facilitated the devel- considerably in Florida over the past 2.5 Ma, opment of a Gulf Coast corridor comprised of perhapscausing of lowland and wet- Savannah and thorn-scrub habitat (Blair 1958, land species(Emslie 1992) this habitat may have Mares 1985, Webb 1985). This corridor allowed endured due to its persistenceon a substrate of speciesadapted to these habitats to disperse to coastaldune featuresand well-drained sands.Al- and from , , Mex- though oak and pine-scrub habitat occurson the ico, Florida, and the southwestern U.S. Numer- Atlantic and Gulf coastsof Florida today, it also ous extinct and extant vertebrate and inverte- occurs on high, central ridges that extend from brate speciesindicate a formerly extensive com- north to south through peninsular Florida that mon habitat throughout theseregions (Stehli and formed as coastal dune deposits during high sea Webb 1985). Although the Plio-Pleistocene rec- levels in the Pliocene and Pleistocene (Woolfen- ord for plant communities in South and Central den and Fitzpatrick 1990). These remnant coast- America is poor, limited evidence suggestsa al featuresallowed this habitat to persist, despite northward expansion of xerophytes and other relatively frequent fluctuations in sea level since plants from the south, and southward expansion at least the late Pliocene. The three late Pleis- from the north, that contributed to a dry thorn- tocene localities from which Aphelocoma coe- scrub community along the Gulf Coast corridor rulescenshas been reported are located on the (Axelrod 1979, Simpson and Neff 1985). Sub- central peninsula near Gainesville, Florida (Fig. sequent climatic events during the Plio-Pleisto- l), the vertebrate faunas of which are not unlike cene fragmented this habitat and isolated pop- that of Inglis 1A in indicating open prairie, wet- ulations of plants and in Florida and the lands, and dry scrub habitat (Brodkorb 1959, western U.S. (e.g., Mengel 1970). Many of these Hamon 1964, Ligon 1965). Additional records isolated populations in Florida became extinct of A. coerulescensmight be expected from other by the end of the Pleistocene (Neil1 1957). The fossil sites located on these ridges. Florida Scrub-Jay and Burrowing Owl (S. cuni- cularia) are the only two avian species with a ACKNOWLEDGMENTS disjunct distribution between Florida and the western U.S. today that also have their center of This project was funded by NSF Grant EAR 94-03206. I thank Frank Pitelka for discussionand comments on distribution in western (Blair the manuscript.D. Steadman,S. Olson, and one anon- 1958). The Crested Caracara (Caracarupluncus) ymous reviewer provided many helpful comments as also has a disjunct distribution between these well. Assistancewith museumcollectiqns was provided 680 STEVEN D. EMSLIE

by Phil Angle, Janet Henshaw, Deb Hill, Storm Olson, Inglis 1A fauna (Irvingtonian), Citrus County, Dave Steadman, and Tom Webber. Florida. Bull. Florida State Mus. Biol. Sci. 27:1- 85. LITERATURE CITED MORGAN,G. S., AND R. HULBERT,JR. 1995. Over- view of the geology and vertebrate paleontology AMERlCANORNITHOLOGIST UNION.’S 1983. Check- of the Leisev Shell Pit Local Fauna. Hillsborouah list of North American birds. 6th ed. American County, Florida. Bull. Florida Mus: Nat. Hist. 57 Ornithologist’s Union, Baltimore, MD. (Part I): l-92. AME~CAN ORNITHOLOOISTUNION.’S 1995. Fortieth NELL, W. T. 1957. Historical biogeographyof pres- supplementto the American Ornithologist’sUnion ent-day Florida. Bull. Florida State Mus. Biol. Sci. check-listof North American birds. Auk 112:819- 2:175-220. 830. PETERSON,A. T. 1992. Phylogeny and rates of mo- AXELROD,D. I. 1979. Age and origin of Sonoran lecularevolution in the Auhelocoma_iavs. _ Auk 109: Desert vegetation.Oct. Pap. Calif. Acad. Sci. 132: 133-147. l-74. PETERSON,A. T. 1993. Adaptive geographicalvari- B~~RAM, W. 1791. Travels throughNorth and South ation in bill shaveof Scrub-Javs(ADhebcoma coe- Carolina,Georgia, east and westFlorida, etc. James rulescens).Am.-Nat.l42:508-527: and Johnson, Philadelphia. PETERSON,A. T., AND N. VARGAS-BARAJAS.1993. BWR, W. F. 1958. Distributional patterns of ver- Ecological diversity in Scrub-Jays (Aphelocoma tebrates in the southern in relation coerulescens),p. 309-3 17. In T. P. Ramamoorthy, to past and present environments, p. 433-468. In R. Bye, and A. Lot [eds.], Biological diversity of C. L. Hubbs [ed.], Zoogeography.American As- Mexico: origins and distribution. Oxford Univ. sociation for the Advancement of Science,Wash- Press, NY. ington, DC. PITELKA,F. A. 1951. Speciation and ecologicdistri- Bose, C. 1795. Description de deux nouvellesesptces bution in American jays of the genusAphelocoma. d’animaux. Bull. Sci., Sot. Philomatique, Paris Univ. Calif. Pub]. Zool. 50: 195-464. 1:87. SIMPSON,B. B., AND J. L. NEFF. 1985. Plants, their BRODKORB,P. 1959. The Pleistoceneavifauna of Ar- pollinating bees, and the great American inter- redondo, Florida. Bull. Florida State Mus. Biol. change, p. 427-452. In F. G. Stehli and S. D. Sci. 41269-291. Webb, [eds.], The great American biotic inter- CARR,G. S. 1981. An early Pleistoceneavifauna from change. Plenum Press, NV. Inglis, Florida. Ph.D. diss., Univ. Florida, Gaines- S-I-EADMAN,D. W. 1980. A review of the osteology ville, FL. and paleontology of turkeys (Aves: Meleagridi- EMSLIE,S. D. 1985. The late Pleistocene (Ranchol- nae). Nat. Hist. Mus. Los Angeles Co., Contrib. abrean) avifauna of Little Box Elder Cave, Wyo- Sci..330: 13I-207. ming. Univ. Wyoming Contrib. Geol. 23:63-82. STEHLI.F. G.. AND S. D. WEBB. 1985. The areat EMSLIE,S. D. 1992. Two new late Blancan avifaunas American’ biotic interchange. Plenum Press,-NY. from Florida and the of wetland birds WEBB,S. D. 1985. Late Cenozoic dispersals in the Plio-Pleistocene. Nat. Hist. Mus. Los An- between the , p. 357-386. In F. G. Stehli geles Co., Sci. Ser. 36~249-269. and S. D. Webb, [eds.], The great American biotic HAMON, J. H. 1964. Osteology and paleontology of interchange.Plenum Press, NY. the passerinebirds of the Reddick, Florida, Pleis- WEBB,S. D. 1990. Historical biogeography,p. 70- tocene.Florida Geol. Sur., GeologyBull.44: l-2 10. 100. In R. L. Myers and J. J. Ewe1[eds.], Ecosys- LIGCIN,J. D. 1965. A Pleistoceneavifauna from Haile, tems of Florida. Univ. of Central Florida Press, Florida. Bull. Florida StateMus. Biol. Sci. 10:127- Orlando, FL. 158. WOOLFENDEN,G. E., AND J. W. FITZPATRICK.1984. MARES,M. A. 1985. Mammal faunasofxeric habitats The Florida Scrub-Jay:demography of a cooper- and the great American interchange,p. 489-520. ative-breeding . Princeton Univ. Press, In F. G. Stehli and S. D. Webb [eds.], The great Princeton, NJ. American biotic interchange.Plenum Press, NY. WOOLFENDEN,G. E., AND J. W. FITZPATRICK.1990. MENGEL,R. M. 1970. The North American central Florida Scrub-Jays:a synopsis after 18 years of plainsas an isolatingagent in bird speciation.Univ. study, p. 239-266. In P. B. Staceyand W. D. Ko- Kansas Dept. Geology, Spec. Pub]. 3:279-340. enig [eds.], in birds. Cam- MEYLAN, P. A. 1982. The squamate of the bridge Univ. Press, Cambridge.