Syngenochilus

Syngenochilus
Holotype of Syngenochilus radiapex
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Neogastropoda
Superfamily:	Conoidea
Genus:	† Syngenochilus Powell, 1944
Type species
Syngenochilus radiapex

Syngenochilus is a genus of minute gastropod molluscs belonging to the superfamily Conoidea, currently unassigned to a family. ^[1] The genus is a fossil taxon, known to occur between the late Eocene to the early Miocene, and has been found in fossil beds in Victoria, Australia.

Description

In the original description, Powell described the genus as below:

This genus resembles the Cancellarid Inglisella , but is actually a small, heavily sculptured Daphnellid close to Teleochilus , but differing from that genus in having an axially ridged protoconch instead of spiral cords. ^[2]

Members of the genus have a small ovate or ovate-fusiform shell measuring up to 7.25 mm (0.285 in), with a bluntly rounded apex. Syngenochilus has a small, flattened protoconch, that has a half whorl with a flattened tip. The following whorl has axial ribs that merge into its teleoconch. ^{[3] [4]}

The genus is visually similar to Parasyngenochilus , but can be differentiated due to Syngenochilus having a flat smooth portion of the protonch, compared to the dome-shape typical of Parasyngenochilus, ^[3] and differentiated from Teleochilus due to the shorter and smaller aperture seen in Syngenochilus. ^[4] S. johannaensis can be differentiated from S. radiapex due to having widely spaced and persistent axial ribbing. ^[3]

Taxonomy

The genus was first described by A. W. B. Powell in 1944, naming S. radiapex as the type species. ^[2] The genus was monotypic until 1981, when D. C. Long described S. johannaensis . ^[3] The holotype of S. radiapex is held by the Auckland War Memorial Museum, ^[5] and S. johannaensis by the National Museum of Victoria. ^[3] The genus was placed in the superfamily Conoidea but excluded from the family Turridae by Yu I Kantor et al. in 2024. ^[6]

Distribution

Syngenochilus fossils have been found in the Jan Juc Formation, Puebla Formation and Glen Aire Clayof the Port Phillip Basin, Torquay, Victoria, Australia, and the Browns Creek Formation of the Otway Basin, Australia. Fossils have been dated to between the late Eocene to the early Miocene. ^{[7] [5]}

Species

Species within the genus Syngenochilus include: ^[1]

• † Syngenochilus johannaensis D. C. Long, 1981
• † Syngenochilus radiapex A. W. B. Powell, 1944

References

1. Syngenochilus A. W. B. Powell, 1944 † . Retrieved through: World Register of Marine Species  on 21 October 2025.
2. Powell, A. W. B. (1944). "The Australian Tertiary Mollusca of the Family Turridae". Records of the Auckland Institute and Museum . 3: 3–68. ISSN   0067-0464. JSTOR   42905993. Wikidata   Q58676624.
3. Long, D. C. (1981). "Late Eocene and early Oligocene Turridae (Gastropoda: Prosobranchiata) of the Brown's Creek and Glen Aire clays, Victoria, Australia". Memoirs of the National Museum of Victoria. 42: 15–55, pls 4–7.
4. Powell, A. W. B. (1 November 1966). "The molluscan families Speightiidae and Turridae: an evaluation of the valid taxa, both recent and fossil, with lists of characteristic species". Bulletin of the Auckland Institute and Museum . 5. Auckland Institute and Museum. ISSN   0067-0456. LCCN   67091267. OCLC   956602. Wikidata   Q115098397.
5. Blom, Wilma M. (2025). "Annotated Catalogue of Fossil and Extant Molluscan Types in the Auckland War Memorial Museum". Bulletin of the Auckland Museum . 22. doi:10.32912/BULLETIN/22. ISSN   1176-3213. Wikidata   Q135397912.
6. Kantor, Yu I; Bouchet, Philippe; Fedosov, Alexander; Puillandre, Nicolas; Zaharias, Paul (December 2024). "Generic revision of the Recent Turridae (Neogastropoda: Conoidea)". Journal of Molluscan Studies. 90 (5) eyae032: 1–40. doi:10.1093/mollus/eyae032.
7. Darragh, Thomas A. (August 2024). "A checklist of Australian marine Cenozoic Mollusca". Memoirs of Museum Victoria. 83: 37–206. doi:10.24199/j.mmv.2024.83.02.