Stephanoconus candidatus (Mayer, 1862)

Plate 5 P 1 -P 2, Q

* Conus candidatus Mayer, in Bronn in Reiss 1862: 23, pl. 1, fig. 1.

Conus candidatus Mayer — Mayer 1864: 78, pl. 7, fig. 58.

Type material. Single specimen, diameter 40.0 mm, height 22.0 mm (incomplete spire fragment), Pinheiros (Baía da Cré), Santa Maria Island, Azores; whereabouts unknown (Beu 2017:165).

Santa Maria material examined. Maximum diameter 19.0 mm (apical fragment of juvenile). DBUA-F 913 (1), Ponta dos Frades, Santa Maria Island, Touril Complex, Lower Pliocene.

Original description. “ Eine Art mit Kronen-f̂rmigem Gewinde, wovon aber nur dieses selbst in einem einfachen Exemplare vorliegt und auf ein 1½" grosses Individuum deutet. Die 9-10 Windungen sind oben mit 3-4 SpiralStreifen versehen, ein wenig nach aussen abfallend, schwach Treppen-f̂rmig abgesetzt und auf der gerundeten Kante mit je 11-12 Knoten geziert. Der obre Theil des letzten Umganges etwas bauchig, glatt. Stimmt (soweit er erhalten) im Ausehen etwas mit C. miliaris Lk., C, nebulosus Solander und zumal C. nocturnus ̧berein; er ist aber etwas minder gestreckt, die Umgänge des Gewindes sind etwas ĥher und schärfer gekantet als an diesem. [A species with crown-shaped suture, of which only this is present as one specimen and points to a 1½" [inches?] tall individual. The 9-10 whorls, slightly sloping outwards and slightly scaled, bear 3-4 spiral threads and the edge bears 11-12 tubercles. The upper part of the last whorl is a bulbous, smooth. Agrees (as far as it is preserved) somewhat with C. miliaris Lk., C. nebulosus Solander and especially also C. nocturnus; but it is somewhat less elongated, the circumferences of the thread are slightly higher and sharper than on this.]” (Bronn in Reiss 1862: 23).

Latin description. “ C. testa mediocri, oblongo-conica; spira acuta, paulum depressa; anfractibus carinatis, scalatis, ad suturam plano-concavis, spiraliter lennuesulcatis, tuberculatisque; tuberculis crassis, obtusis, distantibus.” (Mayer 1864: 78).

Description. Apical fragment. Protoconch missing. Spire strongly depressed, slightly graded. Nine teleoconch whorls preserved, bearing broad, rounded poorly delimited tubercles and fine spiral sculpture.

Discussion. The spire fragment illustrated by Mayer, in Bronn in Reiss (1862: fig. 1) has strong tubercles at the shoulder and can undoubtedly be ascribed to the genus Stephanoconus M̂rch, 1852. This was already noted by Tucker & Tenorio (2009: 125). The spire fragment at hand, from Ponta dos Frades, matches closely the fragment illustrated by Mayer (1864: fig. 58) and clearly shows the tubercles and spiral sculpture on the spire. Stephanoconus is a tropical genus included by Landau et al. (2008, appendix A) in their list of paciphile genera. That is, genera that prior to the closure of the Central America Seaway (CAS) were distributed on both sides of the Isthmus of Panama but became restricted to the Pacific side of their originally wider distribution during or subsequent to the closure. Today Stephanoconus occurs in the eastern Pacific, represented by S. bartschi (Hanna & Strong, 1949). In the Caribbean Neogene it is represented by S. wiedenmayeri Jung, 1965, and several species from the Dominican Republic (NHMW collection) (Hendricks 2015). This record in Santa Maria, Azores is the most western Atlantic for the genus and the only genus with strong tropical western Atlantic rather than Mediterranean affinities in the assemblage.

Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores (Mayer, in Bronn in Reiss 1862; Mayer 1864).

Genus Conus s.l.