Sphaerechinus granularis Lamarck 1816 |
|
Family: Toxopneustidae |
Order: Echinoida |
Locality: Canaries, 2007 |
Dimensions: 54 Ø x 35 mm |
|
|
I got this specimen as "Paracentrotus lividus" from the Canaries, The taxon was apparently wrong. I remarked the high number (up to seven) of the pore pairs, but the following text from Th. Mortensen, A Monograph of the Echinoidea, III. 2, Camarodonta. 1, 1943, page 519, convinced me, that it is really a Sphaerechinus granularis: The pores may form a regular arc, but very often they are arranged so that the lower 2-3 pore-pairs are almost in a straight line along the outer edge, the two upper pairs placed near the primary tubercle, more or less apart from the outer pore-pairs (Fig. 309). The number of pore-pairs is four or five, more rarely six, or even as many as seven. Mortensen remarks furtheron, that the number of pore-pairs does not increase with age in any case, as formerly maintained. One may find big specimens with only 4 pore-pairs and more pore-pairs already in smaller ones. Nevertheless, if Mortensen regarded specimens with six pore-pairs in some arcs as more rare, specimens with seven pore-pairs must be really rare. |