Arachnocorys Haeckel, 1860 , 1887

Trubovitz, Sarah, Renaudie, Johan, Lazarus, David & Noble, Paula, 2022, Late Neogene Lophophaenidae (Nassellaria, Radiolaria) from the eastern equatorial Pacific, Zootaxa 5160 (1), pp. 1-158 : 18-19

Genus Arachnocorys Haeckel, 1860, 1887 , emend. Petrushevskaya, 1971

Type species: Arachnocorys circumtexta ( Haeckel, 1862) Petrushevskaya, 1971

Description. Lophophaenidae with a gap in the shell wall between cephalis and thorax. This gap can be large (as in Arachnocorys circumtexta Haeckel ) or small (as in Arachnocorys umbellifera Haeckel ). The thorax of Arachnocorys typically exhibits ~6–12 strong ribs, and the cephalis has multiple anastomosing spines.

Remarks. This genus was originally described by Haeckel (1860) as having two segments separated by a deep stricture, with many spines on the cephalis and a thorax with strong ribs, resembling the structure and shape of an umbrella. In 1887, Haeckel added to this description of Arachnocorys that there are numerous “siliceous threads” that form an “arachnoidal framework” around the exterior of the shell. Haeckel (1887) listed three subgenera under Arachnocorys : Arachnocorallium , Arachnocoronium , and Arachnocorythium . Petrushevskaya (1971) emended the concept of Arachnocorys to include Haeckel’s subgenus Arachnocoronium but not Arachnocorallium , which she elevated to a separate genus. Haeckel (1887) only included one species under the third subgenus Arachnocorythium ( Arachnocorys polyptera Haeckel ), and he did not illustrate it. Although Campbell (1954) recognized Arachnocorythium as a valid subgenus, with Arachnocorys polyptera Haeckel as the type species, neither the species nor subgenus names have been used in subsequent literature. To our knowledge only one illustration of Arachnocorys (Arachnocorythium) polyptera Haeckel has been published; it was hand-drawn by Popofsky (1913), and it is questionable whether this specimen fits Haeckel (1887) ’s original concept of the species and/or subgenus. Therefore, here we follow Petrushevskaya (1971) ’s concept of Arachnocorys , which includes the broad genus concept defined by Haeckel (1860, 1887) as well as the subgenus concept of Arachnocoronium ( Haeckel, 1887) , but not the subgenera Arachnocorallium (which has been elevated to the genus level) nor Arachnocorythium (which has not been sufficiently documented and may not be distinct from other Arachnocorys ).

Here we observed the following species of Arachnocorys : Arachnocorys circumtexta ( Haeckel, 1862) Petrushevskaya, 1971, Arachnocorys jorogumoae n. sp, Arachnocorys pentacantha (Popofsky, 1913) Petrushevskaya, 1971, Arachnocorys pentacantha wanii n. subsp., Arachnocorys spinosissima (Tan and Tchang, 1976) n. comb., and Arachnocorys umbellifera (Haeckel, 1862) Petrushevskaya, 1971.

We consider the following Arachnocorys species to be nomina dubia, due to a combination of inadequate text description, lack of illustration, and unavailable type materials: Arachnocorys (Arachnocoronium) arachnodiscus Haeckel, 1887 , Arachnocorys (Arachnocorallium) discoides Haeckel, 1887 , Arachnocorys (Arachnocoronium) enneaptera Haeckel, 1887 , Arachnocorys (Arachnocorythium) polyptera Haeckel, 1887 , Arachnocorys (Arachnocoronium) trifida Haeckel, 1887 . Arachnocorys simplex Pantanelli and Stefani, 1879 was misspelled as Arachnocoris simplex n. sp. when the name was first created. No description or illustration was provided by the authors, or any subsequent authors we are aware of, making Arachnocorys simplex Pantanelli and Stefani, 1879 a nomen oblitum. Arachnocorys dubius Dogiel and Reshetnyak, 1952 is not included here because it was transferred by Matsuzaki et al., 2015 to the genus Cryptogyrus given that it does not fit the definition of Arachnocorys . Arachnocorys ? fimbria Kozlova, 1984 was transferred to Ceratocyrtis by the same author in 1999.

Range.?Eocene—Recent.