Truncatoflabellum duncani, Cairns, Stephen D., 2016

Cairns, Stephen D., 2016, A key to the genera and species of the transversely-dividing Flabellidae (Anthozoa, Scleractinia, Flabellidae), with a guide to the literature, and the description of two new species, ZooKeys 562, pp. 1-48 : 18

Taxon classification Animalia Scleractinia Flabellidae

Truncatoflabellum duncani sp. n. Fig. 8C

Flabellum candeanum : Duncan 1864: 163; 1870: 300, pl. 20, fig. 1.

Truncatoflabellum candeanum : Cairns 1989b: 61, pl. 36i-j.

Types.

Holotype: USGS 10809, Mornington, Balcombe’s Bay, Victoria, Balcombian (Middle Miocene), USNM M353592. Paratypes: Muddy Creek, Victoria, Balcombian (Middle Miocene), 3 specimens, USNM 67959; Torquay, Balcombe’s Bay, Victoria, Janjukian (Late Oligocene), 1 specimen, USNM 1295618; 3 miles (=4.8 km) west of river Gellibrand, Otway’s region, Victoria, "Murray Tertiaries" (probably Middle Miocene) (specimen reported by Duncan, 1864, 1870), BM.

Description.

The anthocyathus has straight rounded thecal edges, with an edge angle of 54-72° and face angle of about 27°. The holotype is 30.8 × 18.1 mm in calicular diameter and 28.5 mm in height, with a greater scar diameter of 8.7 mm, similar in size to the specimen reported by Duncan. The GCD:LCD ratio is 1.5-2.1; the H:GCD = 0.95-1.05; and the GSD:GCD is about 0.27, with the scar reaching as long as 12 mm. Four or five pairs of prominent flattened thecal edge spines are present. The septa are quite regularly arranged in five cycles (S1-3>S4>S5), with one pair of S6 in each of the four end half-systems, resulting in 104 septa. The lower axial edges of the larger septa are only slightly sinuous, whereas the upper outer edges are gracefully attenuate, meeting the upper theca as low lamellae. The fossa is open, bordered by the axial edges of the wide S1-3. The anthocaulus is unknown.

Distribution.

Late Oligocene to Middle Miocene, Victoria.

Remarks.

As suggested by the key, Truncatoflabellum duncani is remarkably similar to Truncatoflabellum multispinosum , but can be distinguished by its attenuated upper septal margins. It is also known only from the Oligocene to Miocene of Australia, whereas Truncatoflabellum multispinosum is restricted to the Holocene and Late Pleistocene.

Etymology.

Named in honor Peter M. Duncan, who first discovered specimens belonging to this species.