Holmipterus

Holmipterus Temporal range: Early Wenlock, 433.4 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Restoration of the pretelson and telson of H. suecicus, showing the cercal blades, following Kjellesvig-Waering (1979)
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Order:	†Eurypterida
Superfamily:	†Carcinosomatoidea?
Family:	†Carcinosomatidae?[1]
Genus:	†Holmipterus Kjellesvig-Waering, 1979
Type species
†Holmipterus suecicus Kjellesvig-Waering, 1979

Holmipterus is a problematic genus of eurypterid, an extinct group of aquatic arthropods. The type and only species of Holmipterus, H. suecicus, is known from deposits of Middle Silurian age in the Sweden. The generic name honours Gerhard Holm [sv], a renowned Swedish palaeontologist specialising in arthropods and crustaceans, and the species name suecicus is Latin for 'Swedish'.

Although Holmipterus was a large eurypterid and is known from multiple, albeit partial and fragmentary, specimens, it has proven difficult to determine where it fits in the eurypterid family tree. This is due to the fossil material referred to Holmipterus combining traits seen in different eurypterid groups, such as the Carcinosomatidae and Megalograptidae, and has some distinctive features, such as a telson (the posteriormost division of the body) with two articulating 'cercal blades', forming an organ capable of grasping. Though often classified either as a carcinosomatid or megalograptid, Holmipterus has also been classified as a genus of uncertain affinity within the Eurypterina suborder, or within the entire Eurypterida order. It is possible that the original 1979 description of Holmipterus suecicus reconstructed the telson inaccurately, and/or mistakenly combined fossil material actually belonging to two different genera.