# Taoniinae

Taoniinae is a subfamily containing ten genera of glass squids.

## Description

Unlike Cranchiinae Pfeffer, 1912, the other subfamily within Cranchiidae Prosch, 1847, Taoniinae all lack cartilaginous strips that extend back from the funnel-mantle point of fusion. Their funnels are free laterally, and they have one to three photophores on the eyes. The largest photophore is crescent-shaped for most genera, but it's triangular in Helicocranchia, a semicircle in Bathothauma, and circular in Sandalops. This is in contrast to glass squids in the subfamily Cranchiinae, which have at least four small photophores which are round or oval.
In addition, males lack hectocotyli; these are arms that have evolved to specialize in the storage and transfer of spermatophores to females. Taoniinae are also often larger than Cranchiinae and have darker beaks. Another characteristic is that Taoniinae's caecum, is smaller than its stomach; in Cranchiinae, the caecum is larger than the stomach.

## Taxonomic history and synonyms

When Georg Johann Pfeffer circumscribed this subfamily in 1912, he grouped its genera into three tribes:
* Taonius-like Taoniinae
** Phasmatopsis Rochebrune, 1884
** Toxeuma Chun, 1906
** Taonius Steenstrup, 1861
** Desmoteuthis Verrill, 1881
** Megalocranchia Pfeffer, 1884
** Taonidium Pfeffer, 1900
** Crystalloteuthis Chun, 1906
** Phasmatoteuthion Pfeffer, 1912
** Galiteuthis Joubin, 1898
** Corynomma Chun, 1906
* Teuthowenia-like Taoniinae
** Teuthowenia Chun, 1910
* Bathothauma-like Taoniinae
** Bathothauma Chun, 1906
Synonyms of Taoniinae include Galiteuthinae Berry, 1912 and Teuthoweniinae Grimpe, 1922. S. Stillman Berry's 1912 circumscription of the subfamily Galiteuthinae only consisted of its type genus Galiteuthis Joubin, 1898. Like Pfeffer's Taoniinae, this was a subfamily within the family Cranchiidae Prosch, 1847. This was in contrast to Louis Joubin's classification, which placed Galiteuthis in a new, distinct family: Cranchionychiae Joubin, 1898. Georg Grimpe's 1922 circumscription of Teuthoweniinae included its type genus Teuthowenia Chun, 1910 as well as Hensenioteuthis Pfeffer, 1900, Helicocranchia Massy, 1907, and Sandalops Chun, 1906. He placed the genus Bathothauma Chun, 1906 into a new family, Bathothaumatidae Grimpe, 1922, now just treated as a junior synonym of Cranchiidae. Subsequent research did not pay much heed to Grimpe's taxonomy.

## Phylogeny

Below is Nancy A. Voss and Robert S. Voss's 1983 proposal for a phylogeny of the Taoniinae subfamily.

## Genera and species

As of 2017, the World Register of Marine Species classifies the Taoniinae as containing ten genera; they classify Belonella as a synonym of Taonius following Nancy A. Voss. However, Patrizia Jereb and Clyde F. E. Roper recognize Belonella as a distinct genus from Taonius, although they also note they are frequently synonymized. Jereb and Roper also note Kir Nazimovich Nesis and Takashi Okutani as teuthologists who rejected Voss's synonymization of Belonella. Nesis's classification had Taonius consisting of only the single species T. pavo, and had Belonella consisting of B. belone Chun, 1906, B. borealis Nesis, 1972 and an undescribed species from the Antarctic.
* Genus Bathothauma Chun, 1906
** Bathothauma lyromma Chun, 1906
* Genus Egea Joubin, 1933
** Egea inermis Joubin, 1933
* Genus Galiteuthis Joubin, 1898
** Galiteuthis armata Joubin, 1898, armed cranch squid
** Galiteuthis glacialis (Chun, 1906)
** Galiteuthis pacifica (Robson, 1948)
** Galiteuthis phyllura Berry, 1911
** Galiteuthis suhmi (Hoyle, 1886)
* Genus Helicocranchia Massy, 1907
** Helicocranchia joubini (Voss, 1962)
** Helicocranchia papillata (Voss, 1960)
** Helicocranchia pfefferi Massy, 1907
* Genus Liguriella Issel, 1908
** Liguriella podophthalma Issel, 1908
* Genus Megalocranchia Pfeffer, 1884
** Megalocranchia fisheri (Berry, 1909)
** Megalocranchia maxima Pfeffer, 1884
** Megalocranchia oceanica (Voss, 1960)
* Genus Mesonychoteuthis Robson, 1925
** Mesonychoteuthis hamiltoni, colossal squid or Antarctic cranch squid
* Genus Sandalops Chun, 1906
** Sandalops melancholicus Chun, 1906, sandal-eyed equid
* Genus Taonius Steenstrup, 1861
** Taonius borealis (Nesis, 1972)
** Taonius pavo (Lesueur, 1821)
** Taonius belone (Chun, 1906)
* Genus Teuthowenia Chun, 1910
** Teuthowenia maculata (Leach, 1817)
** Teuthowenia megalops (Prosch, 1849), Atlantic cranch squid
** Teuthowenia pellucida (Chun, 1910), googly-eyed glass squid