introduction to kinorhyncha and...

Sted og dato (Indsæt --> Diasnummer) Dias 1

Martin V. Sørensen

Associate Professor and curator of microscopic invertebrates

Natural History Museum of Denmark

Introduction to

Kinorhyncha and Gnathostomulida

Block course on Zoology and Evolution, Biozentrum, Uni. Basel


Martin V. Sørensen

Associate Professor and curator of microscopic invertebrates

Natural History Museum of Denmark

• Taxonomy, biodiversity, morphology,

and phylogeny

• Kinorhyncha, Priapulida, Loricifera,

Rotifera, Gnathostomulida and

Micrognathozoa

• Metazoan Phylogeny

• Curator of Microscopic Invertebrates

Introduction to

Kinorhyncha and Gnathostomulida


Edgecombe et al. (2011) Higher-level metazoan relationships: Recent progress and remaining questions. Org. Div. Evol.

Ecdysozoa

Platyzoa


Platyzoa and Gnathostomulida

Platyhelminthes Gastrotricha Gnathostomulida

Rotifera (Monogononta – Acanthocephala -

Bdelloidea - Seisonidea)

Gnathifera

Micrognathozoa


Gnathostomulida: Jaw Worms

• Marine, interstitial worms, 100 species



• Ventral mouth leading to blind gut




• Ventral mouth leading to blind gut • Simple cephalic sensory organs

• Simple epidermis with monociliated cells







• Pharynx with hard parts forming jaws

Sted og dato (Indsæt --> Diasnummer) Dias 10 Haplognathia ruberrima

Haplognathia lunulifera Gnathostomula paradoxa

Problognathia minima

Mesognatharia remanei

Tenuignathia rikerae

Rastrognathia macrostoma



Two classes: Filospermoidea Bursovaginoidea



Reproductive mode: • Hermaphrodite • Soft, muscular penis • Filiform sperm cells Reproductive mode:

• Hermaphrodite • Sclerotized penis stylet and dwarf sperm • Or – non-sclerotized penis with giant sperm cells • Female organs with bursa



Order: Scleroperalia

Penis stylet

Testes

Bursa

Ovarium

Spermatozoa


Gnathostomulida:

Biology and distribution

• Sand mixed with detritus

• Never in mud • Never in clean sand, e.g., high energy

beaches



• Discovered in 1928 by Adolf Remane

• Found again in the 1950’ies and described in 1956 as a turbellarian order (Ax, 1956)

• Raised to class level, but still a Platyhelminthes (Ax, 1964)

• Assigned phylum rank, but with uncertain phylogenetic position (Riedl, 1969)

• Independently, Ahlrichs (1995) and Rieger & Tyler (1995) do comparative studies of gnathostomulids and rotifers



Rotifera Gnathostomulida



Micrognathozoa


Platyzoa and Gnathostomulida

Platyhelminthes Gastrotricha Gnathostomulida

Rotifera (Monogononta – Acanthocephala -

Bdelloidea - Seisonidea)

Gnathifera

Micrognathozoa


Kinorhyncha: Mud dragons


Edgecombe et al. (2011) Higher-level metazoan relationships: Recent progress and remaining questions. Org. Div. Evol.

Ecdysozoa

Platyzoa


Ecdysozoa

Kinorhyncha (Mud dragons)

Nematoda (Round worms)

Tardigrada (Water bears)

Arthropoda (Arthropods)

Priapulida (Priapulid

worms)

Loricifera (Girdle

wearers)

Nematomorpha (Gordian worms)

Onychophora (Velvet worms)


Kinorhyncha

• 189 described species

• Marine, meiobenthic

• Present from tidal zone to over 7000 m depth

• Sizes from 130 µm up to 1 mm

• Are composed of a head, a neck and 11 trunk segments


Kinorhyncha Head

Neck

Trunk


Kinorhyncha

Mouth cone

Introvert


Kinorhyncha

Neck

Placids


Kinorhyncha

Placids

Neck

Placids


Kinorhyncha

Plate junctions

Segments


Kinorhyncha

Spines


Kinorhyncha Development through 6 juvenile stages


Kinorhyncha: Global Biodiversity

= only few species reported, or kinorhynch fauna known from a single locality only


Kinorhyncha: Korean Biodiversity Program

• Campyloderes macquariae • Condyloderes megastigma • C. paradoxus • Dracoderes abei • D. orientalis • Dracoderes n. sp. 1 • Echinoderes aspinosus • E. aureus • E. cernunnos • E. koreanus • E. microaperturus • E. obtuspinosus • E. rex • E. tchefouensis • E. ulsanensis • Echinoderes n. sp. 1 • Echinoderes n. sp. 2 • Kinorhynchus yushini • Meristoderes elleae • M. glaber • M. herranzae • M. imugi • Meristoderes n. sp. • Paracentrophyes anurus • Pycnophyes tubuliferus • Pycnophyes n. sp. 1 • Pycnophyes n. sp. 2 • Pycnophyes n. sp. 3 • Pycnophyes n. sp. 4 • Sphenoderes poseidon


Kinorhyncha: Gulf of Mexico Research Initiative

• Antygomonas n. sp. • Echinoderes n. sp. 1 to 11 • Echinoderes spinifurca • Paracentrophyes n. sp. • Pycnophyes n. sp. • Sphenoderes n. sp.


Ecdysozoa






worms)

Loricifera (Girdle

wearers)




Ecdysozoa

Kinorhyncha Nematoda Tardigrada Arthropoda Priapulida Loricifera Nematomorpha Onychophora

Ecdysozoa

• Cuticle formed from microvilli tips • Molting • Ecdysone • Loss of locomotory cilia

Scalidophora Nematoida


Ecdysozoa

Kinorhyncha Nematoda Tardigrada Arthropoda Priapulida Loricifera Nematomorpha Onychophora

Panarthropoda

Segmentation of trunk and limbs

Cycloneuralia

Ring-shaped brain around pharynx



Cycloneuralia:

Scalidophora and Nematoida

Kinorhyncha Nematoda Priapulida Loricifera Nematomorpha


• Introvert + mouth cone • Scalids • Papillar sense organs (flosculi) • Protonephridia

• Unpaired dorsal and ventral nerve strings • Loss of circular muscles • Loss of sperm flagellum • Both sexes with cloaca • Vermiform habitus


Molecular data does not support

Scalidophora

Kinorhyncha Nematoda Priapulida Loricifera Nematomorpha


Plesiomorphies? Adult morphology

18S rRNA

• Introvert + mouth cone • Scalids • Papillar sense organs (flosculi) • Protonephridia

• Unpaired dorsal and ventral nerve strings • Loss of circular muscles • Loss of sperm flagellum • Both sexes with cloaca • Vermiform habitus


Loriciferan – Nematomorph sister groups? Loricifera Nematomorpha


Loricifera Nematomorpha

• Hexaradial symmetry patterns in pharynx, opposed to pentaradial symmetry patterns in Kinorhyncha and Priapulida

Loriciferan – Nematomorph sister groups?


Loricifera Nematomorpha

?

Evolution through Progenesis?

Progenesis: Evolution through sexual maturation of larval stage, which causes the loss of following preadult and adults stages



Evolution through Progenese

Loss of larva

Original cycle maintained

Loss of adult stage through progenesis



The New Ecdysozoan Phylogeny?






worms)

Loricifera (Girdle

wearers)




Thanks!

introduction to kinorhyncha and...

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