Introduction to. Kinorhyncha and Gnathostomulida

Transcription

1 Introduction to Kinorhyncha and Gnathostomulida Block course on Zoology and Evolution, Biozentrum, Uni. Basel Martin V. Sørensen Associate Professor and curator of microscopic invertebrates Dias 1 Natural History Museum of Denmark

2 Introduction to Kinorhyncha and Gnathostomulida Taxonomy, biodiversity, morphology, and phylogeny Kinorhyncha, Priapulida, Loricifera, Rotifera, Gnathostomulida and Micrognathozoa Metazoan Phylogeny Curator of Microscopic Invertebrates Martin V. Sørensen Associate Professor and curator of microscopic invertebrates Dias 2 Natural History Museum of Denmark

3 Ecdysozoa Dias 3 Platyzoa Edgecombe et al. (2011) Higher-level metazoan relationships: Recent progress and remaining questions. Org. Div. Evol.

4 Platyzoa and Gnathostomulida Gnathifera Platyhelminthes Gastrotricha Gnathostomulida Micrognathozoa Rotifera (Monogononta Acanthocephala - Bdelloidea - Seisonidea) Dias 4

5 Gnathostomulida: Jaw Worms Marine, interstitial worms, 100 species Dias 5

6 Gnathostomulida: Jaw Worms Marine, interstitial worms, 100 species Ventral mouth leading to blind gut Dias 6

7 Gnathostomulida: Jaw Worms Marine, interstitial worms, 100 species Ventral mouth leading to blind gut Simple cephalic sensory organs Simple epidermis with monociliated cells Dias 7

8 Gnathostomulida: Jaw Worms Marine, interstitial worms, 100 species Ventral mouth leading to blind gut Simple cephalic sensory organs Simple epidermis with monociliated cells Pharynx with hard parts forming jaws Dias 8

9 Gnathostomulida: Jaw Worms Marine, interstitial worms, 100 species Ventral mouth leading to blind gut Simple cephalic sensory organs Simple epidermis with monociliated cells Pharynx with hard parts forming jaws Dias 9

10 Gnathostomulida: Jaw Worms Haplognathia lunulifera Gnathostomula paradoxa Rastrognathia macrostoma Problognathia minima Tenuignathia rikerae Haplognathia Dias 10 ruberrima Mesognatharia remanei

11 Two classes: Filospermoidea Bursovaginoidea Dias 11

12 Two classes: Filospermoidea Bursovaginoidea Dias 12 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

13 Two classes: Filospermoidea Bursovaginoidea Order: Scleroperalia Ovarium Bursa Testes Penis stylet Dias 13 Spermatozoa

14 Gnathostomulida: Biology and distribution Sand mixed with detritus Never in mud Never in clean sand, e.g., high energy beaches Dias 14

15 Gnathostomulida: Jaw Worms 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 Dias 15

16 Gnathostomulida: Jaw Worms Rotifera Gnathostomulida Dias 16

17 Gnathostomulida: Jaw Worms Micrognathozoa Dias 17

18 Platyzoa and Gnathostomulida Gnathifera Platyhelminthes Gastrotricha Gnathostomulida Micrognathozoa Rotifera (Monogononta Acanthocephala - Bdelloidea - Seisonidea) Dias 18

19 Dias 19 Kinorhyncha: Mud dragons

20 Ecdysozoa Dias 20 Platyzoa Edgecombe et al. (2011) Higher-level metazoan relationships: Recent progress and remaining questions. Org. Div. Evol.

21 Ecdysozoa Kinorhyncha (Mud dragons) Priapulida (Priapulid worms) Loricifera (Girdle wearers) Nematoda (Round worms) Nematomorpha (Gordian worms) Tardigrada (Water bears) Onychophora (Velvet worms) Arthropoda (Arthropods) Dias 21

22 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 Dias 22

23 Head Kinorhyncha Neck Trunk Dias 23

24 Kinorhyncha Mouth cone Introvert Dias 24

25 Kinorhyncha Neck Placids Dias 25

26 Kinorhyncha Neck Placids Placids Dias 26

27 Kinorhyncha Segments Plate junctions Dias 27

28 Kinorhyncha Segments Plate junctions Dias 28

29 Kinorhyncha Spines Dias 29

30 Kinorhyncha Development through 6 juvenile stages Dias 30

31 Kinorhyncha: Global Biodiversity = only few species reported, or kinorhynch fauna known from a single locality only Dias 31

32 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 Dias 32

33 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. Dias 33

34 Ecdysozoa Kinorhyncha (Mud dragons) Priapulida (Priapulid worms) Loricifera (Girdle wearers) Nematoda (Round worms) Nematomorpha (Gordian worms) Tardigrada (Water bears) Onychophora (Velvet worms) Arthropoda (Arthropods) Dias 34

35 Ecdysozoa Ecdysozoa Scalidophora Nematoida Kinorhyncha Priapulida Loricifera Nematoda Nematomorpha Tardigrada Onychophora Arthropoda Dias 35 Cuticle formed from microvilli tips Molting Ecdysone Loss of locomotory cilia

36 Ecdysozoa Cycloneuralia Panarthropoda Scalidophora Nematoida Kinorhyncha Priapulida Loricifera Nematoda Nematomorpha Tardigrada Onychophora Arthropoda Ring-shaped brain around pharynx Segmentation of trunk and limbs Dias 36

37 Cycloneuralia: Scalidophora and Nematoida Scalidophora Nematoida Kinorhyncha Priapulida Loricifera Nematoda 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 Dias 37

38 Molecular data does not support Scalidophora Scalidophora 18S rrna Nematoida Kinorhyncha Priapulida Nematoda 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 Dias 38 Plesiomorphies? Adult morphology

39 Loriciferan Nematomorph sister groups? Loricifera Nematomorpha Dias 39

40 Loriciferan Nematomorph sister groups? Loricifera Nematomorpha Hexaradial symmetry patterns in pharynx, opposed to pentaradial symmetry patterns in Kinorhyncha and Priapulida Dias 40

41 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 Dias 41

42 Loriciferan Nematomorph sister groups? Evolution through Progenese Loss of larva Original cycle maintained Loss of adult stage through progenesis Dias 42

43 The New Ecdysozoan Phylogeny? Nematomorpha (Gordian worms) Loricifera (Girdle wearers) Nematoda (Round worms) Kinorhyncha (Mud dragons) Priapulida (Priapulid worms) Tardigrada (Water bears) Onychophora (Velvet worms) Arthropoda (Arthropods) Dias 43

44 Dias 44 Thanks!