Merostomata (Merostomates)

Merostomata is the name given to a grouping of the extinct Eurypterida (sea scorpions) and the Xiphosura (horseshoe crabs). The term was originally used by James Dwight Dana to refer to Xiphosura only, but was emended by Henry Woodward to cover both groups. The name "Merostomata" derives from the Greek roots μηρός (meros, "thigh") and στόμα (stoma, "mouth"), in reference to the animals possession of appendages which are mouthparts at their proximal end, but swimming legs at their distal end. The scientific consensus at the beginning of the twentieth century was that these two marine groups were closely related, and only more distantly related to the terrestrial Arachnida.More recent analyses suggest that the grouping Merostomata is not monophyletic, with Xiphosura being basal to a clade comprising Eurypterida and Arachnida.[3] It is estimated that the Xiphosura diverged from the Arachnida 480 million years ago.The shared features of the two groups traditionally grouped in the Merostomata are now thought to be retentions of primitive conditions (symplesiomorphies), and thus it has been recommended that the name Merostomata be abandoned.

Source: http://en.wikipedia.org/wiki/Merostomata

Img. 70: A comparison of the aglaspidid Aglaspis spinifer with merostomate Kodymirus vagans

Img. 70:

Eusarcana Strand, 1942		PB1042
Eusarcana Strand, 1942		PB1041
Eusarcana Strand, 1942		PB1040
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. I (454, 3)	Ich454
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. I (454, 2)	Ich454
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. VI, fig. 7	Ich457
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich458
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich488
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. II, Pl. III (counterparts of specimens on Pl. I)	Ich454
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich455
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich443
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. IV, fig. 7, 8	Ich444
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. IV, fig. 2	Ich484
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich482
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich460
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich485
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich479
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. IV, fig. 6	Ich470
Kodymirus vagans Chlupáš et Havlíček, 1965		Ich465
Kodymirus vagans Chlupáš et Havlíček, 1965	Chlupáč a Havlíček (1965), Pl. IV, fig. 4	Ich464

First Previous	Next Last
1 2 3 4 5 6 7 8

Virtual museum of the Czech Geological Survey, www.geology.cz, (C) Czech Geological Survey, 2011, v.0.99 [13.12.2011]