Standard Event System


The "Standard Event System" to Study Vertebrate Embryos was developed in 2009 to establish a common language in comparative embryology. Homologous developmental characters are defined therein and should be recognisable in all vertebrate embryos. The SES includes a protocol on how to describe and depict vertebrate embryonic characters. The SES was initially developed for external developmental characters of organogenesis, particularly for turtle embryos. However, it is expandable both taxonomically and in regard to anatomical or molecular characters. This article should act as an overview on the species staged with SES and document the expansions of this system. New entries need to be validated based on the citation of scientific publications. The guideline on how to establish new SES-characters and to describe species can be found in the original paper of Werneburg.
SES-characters are used to reconstruct ancestral developmental sequences in evolution such as that of the last common ancestor of placental mammals. Also the plasticity of developmental characters can be documented and analysed.

SES-staged species

Overview on the vertebrate species staged with SES.
Major taxon 1Major taxon 2SpeciesReference
LissamphibiaCaudataAmbystoma mexicanum
TestudinesPleurodiraEmydura subglobosa
TestudinesCryptodiraGraptemys nigrinoda
TestudinesCryptodiraKinosternum scorpionoides
TestudinesCryptodiraApalone spinifera, Caretta caretta, Carettochelys insculpta, Chelonia mydas, Chelydra serpentina, Chrysemys picta, Dermochelys coriacea, Eretmochelys imbricata, Lepidochelys olivacea, Natator depressus, Pelodiscus sinensis, Testudo hermanni, Trachemys scripta
CrocodiliaAlligatoridaeAlligator mississippiensis
SquamataLacertidaeZootoca vivipara
SquamataSerpentesBothropoides jararaca
SquamataGymnophthalmidae Calyptommatus sinebranchiatus, Nothobachia ablephara
SquamataVaranidaeVaranus panoptes
SquamataIguanidaePogona vitticeps
AvesGalliformesGallus gallus
MammaliaMonotremataTachyglossus aculeatus
MammaliaMonotremataOrnithorhynchus anatinus
MammaliaMarsupialiaDidelphis virginiana
MammaliaMarsupialiaMonodelphis domestica, Sminthopsis macroura, Dasyurus hallucatus, Dasyurus viverrinus, Phascolarctos cinereus, Petauroides volans, Trichosurus vulpecula, Bettongia gaimardi, Macropus eugenii
MammaliaMarsupialiaCaenolestes fuliginosus
MammaliaXenarthraDasypus hybridus
MammaliaXenarthraBradypus tridactylus
MammaliaAfrotheriaEchinops telfairi, Tenrec ecaudatus
MammaliaAfrotheriaElephas maximus, Loxodonta africana
MammaliaLaurasiatheriaTalpa occidentalis, Talpa europaea, Erinaceus europaeus, Erinaceus roumanicus, Suncus murinus, Crocidura russula, Neomys fodiens, Sorex araneus, Pecari tajacu, Sus scrofa domesticus, Rangifer tarandus, Capreolus capreolus, Bos primigenius taurus, Capra aegagrus hircus, Ovis aries, Phocoena phocoena, Delphinus delphis, Stenella longirostris, Stenella attenuata, Hipposideros armiger, Hipposideros pratti, Molossus rufus, Myotis lucifugus, Myotis myotis, Pipistrellus abramus, Scotophilus kuhlii, Miniopterus natalensis, Miniopterus schreibersii, Carollia perspicillata, Equus ferus caballus, Manis javanica, Felis catus, Mustela putorius, Canis lupus familiaris
MammaliaLaurasiatheriaArtibeus fimbriatus, Artibeus lituratus, Artibeus obscurus, Carollia perspicillata, Eumops patagonicus, Hipposideros armiger, Hipposideros pratti, Miniopterus natalensis, Miniopterus schreibersii, Molossus rufus, Myotis albescens, Myotis lucifugus, Myotis myotis, Pipistrellus abramus, Rhinolophus ferrumequinum, Rousettus aegyptiacus, Rousettus amplexicaudatus, Scotophilus kuhlii, Vespertilio sinensis, Mus musculus
MammaliaBoreoeutheriaOryctolagus cuniculus, Spermophilus citellus, Cavia porcellus, Cricetulus barabensis, Mesocricetus auratus, Myodes glareolus, Meriones unguiculatus, Acomys dimidiatus, Apodemus sylvaticus, Apodemus flavicollis, Apodemus agrarius, Rattus norvegicus, Tupaia javanica, Tupaia belangeri, Galago senegalensis, Nycticebus coucang, Tarsius tarsier, Callithrix jacchus, Erythrocebus patas, Papio cynocephalus, Macaca mulatta, Homo sapiens
MammaliaBoreoeutheriaMus musculus

SES-characters

New SES-characters are continuously described in new publications. Currently, characters of organogenesis are described for Vertebrata, Gnathostomata, Tetrapoda, Amniota, Sauropsida, Squamata, Mammalia, and Monotremata. In total, 166 SES-characters are currently defined.