bimonthly bulletin of the cayman islands department...

BIMONTHLY BULLETIN of the CAYMAN ISLANDS DEPARTMENT of ENVIRONMENT ‘S

TERRESTRIAL RESOURCES UNIT

The Cayman Islands are a hot spot forpaleontology. Specifically, the Caymansare known for vertebrate fossils,including crocodiles, birds, andmammals, dating to about the last15,000 years, or the Pleistocene (alsoknown as the Ice Age) and Holoceneepochs in geological terms. Fossils havebeen found in two types of deposits inthe Caymans; loose sediments in caveson Cayman Brac and Grand Cayman andmangrove peat deposits and “cowwells” on Grand Cayman. Only a fewfossils have been recovered from smallcaves on Little Cayman.

Flicker Bulletin # 29 – FEB / MAR 2017

FOSSIL VERTEBRATES FROM THE CAYMAN ISLANDS

By: Gary Morgan, New Mexico Museum of Natural History

The author (left) and Greg McDonald (right) excavate fossils from a cave on Grand Cayman in 1976.

The first person to discover vertebratefossils in the Cayman Islands was LordMoyne, who found fossils of a largerodent in a cave at Stake Bay on CaymanBrac in 1937. The next year, BernardLewis from the Institute of Jamaica, amember of the legendary OxfordUniversity Biological Expedition to theCayman Islands, collected additionalfossils of a large rodent in a cave onCayman Brac. In 1964, Thomas Pattonfrom the Florida State Museum (nowthe Florida Museum of Natural History)at the University of Florida exploredCayman Brac in search of fossilvertebrates.

He discovered large samples of fossilreptiles, birds, and mammals in twocaves on Cayman Brac, since namedPatton’s Fissure and Pollard Bay Cave.

As a beginning graduate student at theUniversity of Florida (UF) in 1975, I wasrecruited by Patton to study the fossilvertebrates from the Cayman Islands formy Masters Thesis. Having grown up ina small town in Ohio, I was thrilled withthe opportunity to do field work andresearch on a tropical island group inthe Caribbean. My first field trip to theCayman Islands was in 1976, with fellowUF students Greg McDonald and NinaThanz, which began a 20 yearpaleontological odyssey that includedfour more trips to the Caymans tocollect fossils in 1979, 1980, 1986, and1993.


Until the late 1970s, all vertebratefossils from the Cayman Islands hadbeen recovered from caves on CaymanBrac and Grand Cayman. That changeddramatically with two importantdiscoveries on Grand Cayman. In 1979,Edward and Robert Materne found alarge number of darkly stained bonesprotruding from piles of organicsediment (peat) excavated from amosquito control canal in a mangroveswamp north of George Town. Laterthat same year, the Maternes tookthose bones to the U. S. NationalMuseum of Natural History, part of theSmithsonian Institution in Washington,DC, where I was working at the time.Much to my surprise, almost their entiresample of fossils belonged to crocodiles,including a nearly complete skull –seebelow.

Fossil skull of the Cuban crocodile (Crocodylus rhombifer) from the Crocodile Canal site, Grand Cayman. Dorsal (top) view on left, ventral (bottom) view on right.

This site has since been named theCrocodile Canal. Also in the late 1970s,Grand Cayman residents Rolin Chisholmand Ira Thompson collected a secondlarge sample of crocodile bones, fromdark organic sediments removed from acow well on Chisholm’s property nearNorth Side (see below). Cow wells aresmall, water-filled depressions in thelimestone that often contain peatdeposits and fossils, primarilycrocodiles.

Over the next two decades, severaladditional samples of crocodile fossilswere found on Grand Cayman, includinga water-filled cave in a bananaplantation at Furtherland Farms in 1986and a cow well on the grounds of theQueen Elizabeth II Botanic Park in 1993.


The author (left) and Rolin Chisholm (right) collect fossils of the Cuban crocodile from a cow well on Grand Cayman in 1986.

The Ice Age fossil vertebrates from theCayman Islands represent an interestingmix of species that still occur in theislands, including frogs, lizards, snakes,birds, and bats, together with crocodilesand numerous species of birds andmammals no longer found in theCaymans. Some of these species arecompletely extinct, while others arelocally extinct in the Cayman Islands butstill live elsewhere in the West Indies,primarily in Cuba or Jamaica.

Crocodiles are the largest fossilvertebrates recovered from the CaymanIslands. Study of the cranial anatomy ofabout a half dozen crocodile skulls fromGrand Cayman (see photos) reveals thatthey belong to the rare Cuban crocodile(Crocodylus rhombifer), rather than themore

more common and widespreadAmerican crocodile (Crocodylus acutus).

Cuban crocodiles are now restricted toseveral freshwater swamps in Cuba,although the fossil record reveals thatthis crocodile was considerably morewidespread in the past, with locallyextinct populations on Grand Cayman,many islands in the Bahamas, and theDominican Republic. The Cubancrocodile is one of the most terrestrialof all living crocodilian species, and isknown to prey on large rodents calledhutias that are known as fossils from theCayman Islands (see below).

The past presence of crocodiles onGrand Cayman was mentioned inseveral historical documents, including abook about Sir Francis Drake’s visit toGrand Cayman in 1586 and referencesby Captain William Jackson in 1642 andEdward Long in 1774. The name of theCayman Islands was almost certainlyderived from the former abundance ofcrocodiles on Grand Cayman.


The Spanish word caimán (from theCarib cayman) is the name used fortropical American crocodiles. TheSpanish name for the island group isIslas Caimán, the “Crocodile Islands.”The resident population of crocodilesdisappeared from Grand Cayman in the1800s, probably resulting fromoverhunting.

Fossil birds from the Cayman Islandsinclude four extinct species and sevenspecies now absent from the Caymansbut still found on other islands in theWest Indies. Bones of an eagle-sizedraptor (Titanohierax gloveralleni) werefound in a small cave near East End onGrand Cayman.

Top right: Fossil skull of the extinct rodent or hutia (Capromys) from Cayman Brac, on the right is a photo of the Cuban hutia (Capromys pilorides) (Photo by Nancy Albury). Below: Jaws and teeth of

hutias from a cow well on the grounds of the Botanic Park. These fossils are strongly corroded because they were eaten and digested by a crocodile.

This large bird is also known from fossildeposits in Cuba, Hispaniola, and theBahamas. Titanohierax was a giganticAntillean hawk related to the great blackhawk (Buteogallus urubitinga) from thetropics of Central and South America. Itprobably fed on several species of largerodents that are also now extinct in theCaymans.

Another large predatory bird, an extinctcaracara (Caracara creightoni), wasidentified from a cave on GrandCayman, and is also known by fossilsfrom the Bahamas. An extinct species ofbullfinch (Melopyrrha latirostris) wasdescribed from a cave on Cayman Brac.This extinct bullfinch is much larger thanthe similar Cuban bullfinch (Melopyrrhanigra) that still lives on Grand Caymanand Cuba (see photos).


Top row, left: fossil beak of an extinct species of bullfinch (Melopyrrhalatirostris) from Cayman Brac;

right: skull of a modern Cuban bullfinch (Melopyrrha nigra) from Cuba.

Bottom: stamp from the Cayman Islands with the Cuban bullfinch.

The fourth extinct bird from theCaymans, a large snipe (Capella) foundin two caves on Cayman Brac, is alsoknown from fossil cave deposits in theBahamas. Birds identified as fossils fromGrand Cayman or Cayman Brac but nowlocally extinct in the Caymans include:Audubon’s shearwater (Puffinuslherminieri), plain pigeon (Columbainornata), Key West quail dove(Geotrygon chrysia), great lizard cuckoo(Saurothera merlini), burrowing owl(Athene cunicularia), and Cuban crow(Corvus nasicus). This latter groupincludes one additional bird that is ofexceptional interest, a hummingbird!

Fossils of a tiny bird from a cave on thenorth coast of Grand Cayman are verysimilar to bones of the Cuban emerald(Chlorostilbon ricordii), a hummingbirdnow found in Cuba and the Bahamas(see the front cover). The Caymans areone of the only island groups in theWest Indies that lack hummingbirds inthe modern fauna. We now know theyinhabited Grand Cayman in the recentpast but went extinct here for someunknown reason.

The living mammal fauna of the CaymanIslands consists entirely of bats,including eight species. Fossils from theCayman Islands add five extinct speciesof terrestrial or non-volant mammals(i.e., not bats), as well as five additionalspecies of bats now locally extinct in theCaymans. There are two new species ofthe small, shrew-like insectivoreNesophontes, one each from CaymanBrac and Grand Cayman. Nesophontes isalso known from fossil deposits in Cuba,Hispaniola, and Puerto Rico.

It is an extinct genus distantly related tothe larger insectivore Solenodon thatstill lives in Cuba and Hispaniola. Fossilsfrom Grand Cayman, Cayman Brac, andLittle Cayman represent several extinctspecies of large rodents the size of ahouse cat, called hutias or coneys,referred to the genera Capromys andGeocapromys. The larger of these tworodents, Capromys, has a longer tail andis primarily arboreal, while the smallerGeocapromys has a short tail and ismostly terrestrial in its habits.

These two genera belong to a WestIndian rodent family of South Americanorigin, and are distantly related toguinea pigs. There are several livingspecies of Capromys in Cuba (see page5), and species of Geocapromys are stillfound in Jamaica and the tiny island ofEast Plana Cay in the Bahamas. Asimilar-sized rodent, the agouti (locallycalled “rabbit”), still lives on GrandCayman. It was introduced from CentralAmerica more than 100 years ago.

Cayman


Within the past few years, several newfossil finds have been made in theCayman Islands. Caymanian residentshave collected half a dozen fossil skullsof hutias, including both Capromys andGeocapromys, as well as crocodile skullsand Pat Shipman and Alan Walker foundfossils of Capromys in a cave on LittleCayman. Undoubtedly, new discoveriesof fossil vertebrates remain to be madein the Cayman Islands.

Suggested reading:• Morgan, G. S. 1994. Late Quaternary fossil

vertebrates from the Cayman Islands. Chapter in:The Cayman Islands: Natural History andBiogeography, M. A. Brunt and J. E. Davies, KluwerAcademic Publishers, Dordrecht, Netherlands.

• Morgan, G. S. and N. A. Albury. 2013. The Cubancrocodile (Crocodylus rhombifer) from LateQuaternary fossil deposits in the Bahamas andCayman Islands. Bulletin of the Florida Museum ofNatural History, v. 52, no. 3, p. 161–236.

• Morgan, G. S., R. Franz, and R. I. Crombie. 1993.The Cuban crocodile, Crocodylus rhombifer, fromLate Quaternary fossil deposits on Grand Cayman.Caribbean Journal of Science, vol. 29, p. 153–164.

• Steadman, D. W. and G. S. Morgan. 1985. A newspecies of bullfinch (Aves: Emberizinae) from a LateQuaternary cave deposit on Cayman Brac, WestIndies. Proceedings of the Biological Society ofWashington, vol. 98, p. 544–553.

Four skulls of fossil rodents (hutias) from a cave on Cayman Brac. The three skulls on the left are covered by a layer of white calcite flowstone from the cave.


Dr. Rosenthal examines the tagged and beaded Sister Island Rock Iguana after it reportedly had been hit by a car and taken in by Bonnie Scott-Edwards.

the members of the group. While Dr.Rosenthal prescribed continuedtreatment for the iguana which wasconcussed from being hit by a car, shethought the parrots were well enoughfor a soft release programme.

Since the formation of this wildliferescue team, the group has alreadynursed and provided care for a SisterIsland Rock Iguana, a juvenile SnowyEgret and two Cayman Brac parrots!

The wildlife on Cayman Brac is clearly inneed of a support group like this one.Prior to this initiative, Ms. Bonnie has,with support from husband Gene, takencare of countless of animals from WestIndian whistling ducks, owls, white-crowned pigeons, tropic birds, boobies,frigates, parrots and egrets to curly-tailed lizards, iguanas and snakes!

as, or.

Wildlife Rescue on Cayman Brac

An amazing new initiative led by DoEvolunteer Bonnie Scott-Edwards aims toformally establish a wildlife rescueresponse group on Cayman Brac.

Since forming in January this year, the“Brac Wildlife Rehab Group” has held itsfirst monthly meeting with members:Bonnie Scott-Edwards, Barbara Redman-White, Caroline Dowd, Carys Jane,Debra Vascik, Donna McMurtry, DorisBlack, Helen LeRoy, Lorraine Theoret,and Marcia Tucker. The Dean of theSchool of Veterinary Medicine at St.Matthew’s University, Dr. KarenRosenthal, was fortunately able to jointhis very first meeting.

Dr. Rosenthal examined the currentpatients, namely a Sister Island RockIguana and two Cayman Brac parrotsand was able to offer advice and tips tothe


Above: Bonnie tube-feeding a juvenile egret with help from the Seabird Project team, and below: two rescue Brac parrots rehabbed and ready for release!

areas, or.

Meeting every second Saturday of themonth, the Brac Wildlife Rehab Group isnot turning away any animal in need.With donations of medical suppliesfrom the Faith Hospital and full supportfrom the Terrestrial Resources Unit atthe DoE (we help coordinate veterinaryassistance and inter-island transport ofanimals, we provide supplies andtechnical assistance where we are ableand we organize meetings with otherGovernment Departments such as theRCIPS), the group can benefit greatlyfrom every interested individual.

Whether you want to donate equipmentor money, volunteer your time or helptake care of wildlife on the Brac –thereis a space for you!

Please visit the group’s Facebook page:

for updates, lists of needed equipmentand heart warming stories and photos.Alternatively you can call the IguanaHotline on:

+1 (345) 917-7744

and report injured wildlife or find outexactly how you can help!

https://www.facebook.com/search/top/?q=brac%20wildlife%20rehab%20group



Buttonwood (Conocarpus erectus) isoften found among mangrove speciesbut differs by reproducing throughseeds. Buttonwood naturally occurs intwo main varieties; green buttonwoodwhich is the most common variety whilethe silver buttonwood (Conocarpuserectus sericeus) is often used forgardens in hedges and landscaping.

This evergreen is a highly salt tolerantplant and it also tolerates frequentflooding and wet soil making it a highlyattractive plant around the CaymanIslands where reclaimed and low-lyingland is common. It further has lownutrient requirements making it cheapto propagate or sow.

KNOW YOUR NATIVESBUTTONWOOD


Buttonwood is a low-branching shrub ortree growing to a typical 10.5 meters(~35 ft.), and this erect tree hasalternate leaves and inconspicuouswhite flowers.

As buttonwood flower and fruitthroughout the year, it is a veryimportant native species providing bothfood and cover for wild birds. Thebrownish red fruit look like old leatherbuttons, hence giving the plant itscommon name.

While buttonwood can be found inland,it is a seaside shrub or tree offeringprotection and retention of the soil andbanks during storm surges.

Buttonwood (left: green and right: silver) with its attractive foliage. Photos by Mat Cottam

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