Media Releases

Burgess Shale fossil site gives up oldest evidence of brood care

December 17, 2015

508 million-year-old Waptia found to have eggs containing preserved embryos

TORONTO, ON — Long before kan­ga­roos car­ried their joeys in their pouch­es and hon­ey bees nur­tured their young in hives, there was the 508-mil­lion-year-old Wap­tia. Lit­tle is known about the shrimp-like crea­ture first dis­cov­ered in the renowned Cana­di­an Burgess Shale fos­sil deposit a cen­tu­ry ago, but recent analy­sis by sci­en­tists from the Uni­ver­si­ty of Toron­to, Roy­al Ontario Muse­um, and Cen­tre nation­al de la recherche sci­en­tifique has uncov­ered eggs with embryos pre­served with­in the body of the ani­mal. It is the old­est exam­ple of brood care in the fos­sil record.

“As the old­est direct evi­dence of a crea­ture car­ing for its off­spring, the dis­cov­ery adds anoth­er piece to our under­stand­ing of brood care prac­tices dur­ing the Cam­bri­an Explo­sion, a peri­od of rapid evo­lu­tion­ary devel­op­ment when most major ani­mal groups appear in the fos­sil record,” said Jean-Bernard Caron, cura­tor of inver­te­brate palaeon­tol­ogy at the Roy­al Ontario Muse­um and asso­ciate pro­fes­sor in the Depart­ments of Earth Sci­ences and Ecol­o­gy & Evo­lu­tion­ary Biol­o­gy at the Uni­ver­si­ty of Toron­to.

Caron, along with Jean Van­nier at the Cen­tre nation­al de la recherche sci­en­tifique in Lyon, France, describe the find­ings in a study pub­lished Decem­ber 17 in Cur­rent Biol­o­gy.

Wap­tia field­en­sis is an ear­ly arthro­pod, belong­ing to a group of ani­mals that includes lob­sters and cray­fish. It had a two-part struc­ture cov­er­ing the front seg­ment of its body near the head, known as a bivalved cara­pace. Caron and Van­nier believe the cara­pace played a fun­da­men­tal role in how the crea­ture prac­tised brood care.

“Clus­ters of egg-shaped objects are evi­dent in five of the many spec­i­mens we observed, all locat­ed on the under­side of the cara­pace and along­side the ante­ri­or third of the body,” said Caron.

The clus­ters are grouped in a sin­gle lay­er on each side of the body with no or lim­it­ed over­lap­ping among the eggs. In some spec­i­mens, eggs are equidis­tant from each oth­er, while in oth­ers, some are are clos­er togeth­er, prob­a­bly reflect­ing vari­a­tions in the angle of bur­ial and move­ment dur­ing bur­ial. The max­i­mum num­ber of eggs pre­served per per indi­vid­u­als prob­a­bly reached 24.

“This crea­ture is expand­ing our per­spec­tive on the diver­si­fi­ca­tion of brood care in ear­ly arthro­pods,” said Van­nier, the co-author of the study. “The rel­a­tive­ly large size of the eggs and the small num­ber of them, con­trasts with the high num­ber of small eggs found pre­vi­ous­ly in anoth­er bivalved arthro­pod known as Kun­min­gel­la dou­villei. And though that crea­ture pre­dates Wap­tia by about sev­en mil­lion years, none of its eggs con­tained embryos.”

Kun­min­gel­la dou­villei also pre­sent­ed a dif­fer­ent method of car­ry­ing its young, as its eggs were found low­er on the body and attached to its appendages.

The pres­ence of these two dif­fer­ent parental strate­gies sug­gests an inde­pen­dent and rapid evo­lu­tion of a vari­ety of meth­ods of parental care of off­spring. Togeth­er with pre­vi­ous­ly described brood­ed eggs in ostra­cods from the Upper Ordovi­cian peri­od 450 mil­lion years ago, the dis­cov­ery sup­ports the the­o­ry that the pres­ence of a bivalved cara­pace played a key role in the ear­ly evo­lu­tion of brood care in arthro­pods.


The research appears in a study titled “Wap­tia and the diver­si­fi­ca­tion of brood care in ear­ly arthro­pods” pub­lished in Cur­rent Biol­o­gy. It was sup­port­ed by a Nat­ur­al Sci­ences and Engi­neer­ing Research Coun­cil of Cana­da Dis­cov­ery Grant to Jean-Bernard Caron, an ANR (Agence Nationale de la Recherche) Grant to Jean Van­nier, and the Uni­ver­si­ty of Lyon.

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Jean-Bernard Caron (bilin­gual — Eng­lish-French)
Cura­tor of Inver­te­brate Palaeon­tol­ogy, Roy­al Ontario Muse­um and Asso­ciate Pro­fes­sor, Depart­ment of Ecol­o­gy and Evo­lu­tion­ary Biol­o­gy and
Depart­ment of Earth Sci­ences, Uni­ver­si­ty of Toron­to

Jean Van­nier
Senior Researcher
Lab­o­ra­toire de géolo­gie de Lyon: Terre, Planètes, Envi­ron­nement (UMR 5276-CNRS)
+33 4 7244 8144

Sean Bet­tam
Com­mu­ni­ca­tions, Fac­ul­ty of Arts & Sci­ence
Uni­ver­si­ty of Toron­to


David McK­ay
Com­mu­ni­ca­tions Coor­di­na­tor
Roy­al Ontario Muse­um