A New Ordovician Eurypterid
Book Details
Author(s)Ellis William Shuler
ISBN / ASINB00DBMRWG4
ISBN-13978B00DBMRWG2
Sales Rank2,183,859
MarketplaceUnited States 🇺🇸
Description
"[...]barren of fossils.
Stylonurus (Ctenopterus)? alveolatus sp. n.
The Eurypterid fragments consist of parts of four post-oral limbs; a part of the telson spine with the impression of two abdominal segments, and a fragmentary carapace.
The best preserved fragment is that belonging to the second or third endognathite, fig. 4. It consists of three segments, all of which, after making allowance for mashing due to the conditions of preservation, show a distinct dorsi-ventral flattening. The articulation of the joints is such as to permit flexing movements downward and backward, an arrangement which suggests an adaptation of the limb to swimming. The individual segments are distinctly elongated, being on the average twice as long as wide. The lengths of the successive segments beginning with the proximal one are: 16mm, 16mm, and 20mm. The corresponding widths are: 10mm, 8mm, and 6mm.
The posterior margin of the proximal joint is supplied with two prominent spines or flattened bristles, the larger of which occupies the distal corner. This is the largest spine preserved. It has a length of 41mm. The width, 2mm, is fairly uniform along its whole length. In common with the other spines it originates in a projecting alveolar process or ring-like swelling of the integument at the base, which from its unusual development, is a significant characteristic of this species. The smaller
Figs. 1-6.
[...]".
Stylonurus (Ctenopterus)? alveolatus sp. n.
The Eurypterid fragments consist of parts of four post-oral limbs; a part of the telson spine with the impression of two abdominal segments, and a fragmentary carapace.
The best preserved fragment is that belonging to the second or third endognathite, fig. 4. It consists of three segments, all of which, after making allowance for mashing due to the conditions of preservation, show a distinct dorsi-ventral flattening. The articulation of the joints is such as to permit flexing movements downward and backward, an arrangement which suggests an adaptation of the limb to swimming. The individual segments are distinctly elongated, being on the average twice as long as wide. The lengths of the successive segments beginning with the proximal one are: 16mm, 16mm, and 20mm. The corresponding widths are: 10mm, 8mm, and 6mm.
The posterior margin of the proximal joint is supplied with two prominent spines or flattened bristles, the larger of which occupies the distal corner. This is the largest spine preserved. It has a length of 41mm. The width, 2mm, is fairly uniform along its whole length. In common with the other spines it originates in a projecting alveolar process or ring-like swelling of the integument at the base, which from its unusual development, is a significant characteristic of this species. The smaller
Figs. 1-6.
[...]".
