Schmalenseeia


Schmalenseeia is genus of trilobites of uncertain affinity, that lived during the middle Middle to earliest Upper Cambrian. Species assigned to Schmalenseeia have been found in Norway, Sweden, Northern Siberia, Eastern China, Australia, India and the United Kingdom.

Etymology

Schmalenseeia was named in honor of C.G. von Schmalensee, who collected the first specimen.
  • The species epithet arthrotryphe is derived from the Ancient Greek 'athroos' meaning "crowded" and 'tryphos', "part", referring to the large number of segments.

Taxonomy

The first species of Schmalenseeia to occur in the fossil record, S. acutangula, must have developed from an early species of Burlingia. It is intermediate between the two genera. The affinities of the family Burlingiidae to which Schmalenseeia has been assigned remain uncertain. Schmalenseeia shares many features with Kleptothule, such as a glabella tapering forward and a prominent preglabellar ridge, but a close relationship seems unlikely due to the apparent lack of facial sutures and the much earlier appearance in the fossil record of Kleptothule.

Species previously assigned to ''Schmalenseeia''

S. jagoi = ''Burlingia jagoi''

Description

Like all burlingiids, Schmalenseeia is small, has an overall ovate shape, proparian facial sutures, and raised anterior borders of the pleura. Schmalenseeia has between 7 and 9 thorax segments, while Burlingia has between 10 and 15. In Burlingia it is however difficult to determine where the thorax meets the pygidium, particularly because uniquely, the pleurae of the pygidium are not fused. All Schmalenseeia-species with the exception of S. acutangula have a glabella that tapers forward, and is connected with the anterior border by a ridge.

Distribution

S. acutangula is known from the Middle Cambrian of S. amphionura has been found in the Upper Cambrian of India, Sweden, the United Kingdom.S. arthrotryphe occurs in the Upper Cambrian of.S. gostiensis is known from the Middle Cambrian of Australia.S. longa was excavated from the Middle Cambrian of Eastern China.S. sinensis is present in the Middle Cambrian of Eastern China.S. spinulosa occurs in the Upper Cambrian of Northern Siberia.S. transversa is present in the Middle Cambrian of Eastern China.