Tritoniopsis Eliot 1905

Silva, Felipe De Vasconcelos, Pola, Marta & Cervera, Juan Lucas, 2023, A stomach plate to divide them all: a phylogenetic reassessment of the family Tritoniidae (Nudibranchia: Cladobranchia), Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 199 (2), pp. 445-476 : 464

publication ID	https://doi.org/ 10.1093/zoolinnean/zlad013
publication LSID	lsid:zoobank.org:pub:C3E2DFF9-A0A6-41EA-A149-0F73A2BEE5E6
DOI	https://doi.org/10.5281/zenodo.8432413
persistent identifier	https://treatment.plazi.org/id/03A6878C-FF83-6503-FFAB-FC68ECE7FD8A
treatment provided by	Plazi
scientific name	Tritoniopsis Eliot 1905
status

Treatment

Tritoniopsis Eliot 1905 View in CoL

( Figs 3C View Figure 3 , 4C View Figure 4 , 5C View Figure 5 , 6C View Figure 6 )

Tritoniopsilla Pruvot-Fol 1933 , Mem. L’ Inst. D’ Egypte, 21: 90.

Type species: Tritoniopsis brucei Eliot 1905 View in CoL , by original designation.

Diagnosis: Alternate oral processes. Numerous, fully arborescent gills. Rachidian tooth unicuspid and denticulate, first lateral tooth undifferentiated, few lateral teeth per row.

Morphology: Body slightly broad, length up to 100 mm ( Fig. 3C View Figure 3 ). Oral veil broad, bilobed or entire. Nine to 13 velar processes alternating in size. Fourteen to 20 pairs of arborescent gills, mostly uniform. Ratio jaw/body length: 0.11–0.15. Rachidian tooth unicuspid ( Fig. 4C View Figure 4 ). Central cusp strong, sharp and long; small denticles present in the lower region of the base. Laterals slender, hooked and sometimes denticulate. Small number of lateral teeth (up to ten per half row). Masticatory borders of jaws differentiated or smooth. Cuticular folds absent. ODG complex large (more than two-thirds of total animal length) ( Fig. 5C View Figure 5 ). Gonopore at one-third of body length, furthest from rhinophores. Anus and nephroproct at midbody length or beyond. Female gland mass large ( Fig. 6C View Figure 6 ). Bursa copulatrix pyriform or oval. Penis flagelliform or conical.

Species composition: Tritoniopsis brucei , Tritoniopsis elegans and Tritoniopsis flydis .

Remarks: Apartfromthediagnosticsynapomorphies, Tritoniopsis is characterized by medium-sized species (up to 100 mm) with an elongated ODG complex, and a large female gland mass ( Odhner 1936, Er. Marcus and Ev. Marcus 1970). The masticatory border of the jaw is smooth in Tritoniopsis brucei and Tritoniopsis elegans ( Eliot 1905, Yonow 2017), and differentiated as comprised of irregular cell-like structures in Tritoniopsis flydis (Er. Marcus and Ev. Marcus 1970) . Tritoniopsis was recovered as a sister group to Marianina in our phylogenetic analyses ( Table 2 View Table 2 ). Both genera have unicuspid and denticulate rachidian teeth which are easily distinguished: the unicuspid rachidian of Tritoniopsis is stronger with a few small denticles in the lower region of the base ( Fig. 4C View Figure 4 ), while the unicuspid rachidian of Marianina is narrower and fully denticulate with larger cusps ( Odhner 1936).