Microcancilla phoenix, Souza & Pimenta & Miyaji, 2021

Souza, Leonardo Santos de, Pimenta, Alexandre Dias & Miyaji, Cintia, 2021, A new species of Microcancilla from the southwestern Atlantic and notes on Microcancilla brasiliensis comb. nov. (Gastropoda, Cancellariidae), Papéis Avulsos de Zoologia 61, pp. 1-8 : 2-5

Microcancilla phoenix sp. nov.

http://zoobank.org/ 60489198-E5B0-4CE3-968D-B66EEB5DB937 ( Figs. 1 A-H, 2A-F)

Axelella brasiliensis – Wiggers & Veitenheimer-Mendes (2003: 58, fig. 15); Forcelli & Narosky (2015: pl. 5, fig. 1) (non Verhecken, 1991).

Type material: Holotype MNRJ 60299 . Paratypes: BRAZIL: São Paulo: PADCT stn. 6627: MNRJ 28192 † [1] ; REVIZEE Sul stn. 6658: MNRJ 60302 [1] ; Paraná: REVIZEE- Sul stn. 6652: MNRJ 23200 † [54], MNRJ 28183 † [1] .

Type locality: BRAZIL: Santa Catarina: PADCT stn. 6595 (26°23′32″S, 46°39′29″W, 175 m), coll. RV Prof.W.Besnard, xi.1997 - i.1998.

Additional material examined: BRAZIL: from type locality: MNRJ 28191 † [1], MNRJ † [9] ; Rio de Janeiro: PADCT stn. 6541: MNRJ † [2] ; PADCT stn. 6553: MNRJ 28188 † [1] ; PADCT stn. 6627: MNRJ † [2]; São Paulo: REVIZEE-Sul stn. 6669: MNRJ 28189 † [3] ; REVIZEE-Sul stn. 6660: MNRJ † [1]; PADCT stn. 6579: MNRJ 28184 † [3] ; REVIZEE-Sul stn. 6680: MNRJ † [1]; Paraná: REVIZEE-Sul stn. 6651: MNRJ † [2] ; Santa Catarina: PADCT stn. 6635: MNRJ 28187 † [4] ; PADCT stn. 6601: MNRJ 28186 † [4] ; PADCT stn. 6608: MNRJ † [8]; PADCT stn. 6611: MNRJ † [1].

Description: Shell conical, spire short, whitish, reaching 4.25 mm long and 2.41 mm wide.Protoconch paucispiral, globose, covered by microscopic pustules, 1.25 whorls, 600 µm long, 700 µm wide, transition distinguishable by emergence of axial sculpture of teleoconch. Teleoconch with 3.0 slightly convex whorls, reticulated, shouldered; suture well-demarcated, with small, almost flat subsutural region ornamented by axial cords, nodulated at margin. Last whorl occupying 70% of whole shell length, with six spiral cords between sutures and about 20 axial cords since outer lip. Base slightly sinuous, with three to four spiral cords. Aperture wide, almost elliptical, round- ed posteriorly, more constricted anteriorly at slightly elongated siphonal canal. Outer lip thin, prosocline. Inner lip sinuous, reflected, slightly folded about middle; presence of very minute umbilical chink behind inner lip.

Measurements: Holotype: whorls = 3.0; SL = 2.85 mm; BWL = 2.24 mm; AL = 1.42 mm; SW = 1.68 mm; AW = 0.98 mm. Paratype MNRJ 28183: Whorls = 4.25; SL = 4.20 mm; BWL = 3.01 mm; AL = 1.81 mm; SW = 2.41 mm; AW = 1.31 mm.

Etymology: phoenix (Latin) refers to a fabled bird symbolic of resurrection and immortality; the epithet is named in honor of the “Museu Nacional”. Epithet as a noun in apposition.

Geographic distribution: BRAZIL: from Rio de Janeiro (this study) to Rio Grande do Sul (Wiggers &Veitenheimer- Mendes, 2003; Forcelli & Narosky, 2015) .

Bathymetric range: From 50 m to 490 m.

Remarks: The previously selected type series of M. phoenix sp. nov., including the holotype, was destroyed by the fire of “Museu Nacional”. An additional shell was obtained later; in spite of it being a young- er and partially broken shell, we choose a preserved specimen as the name-bearing type of M. phoenix ( Fig. 1A ).

Some shells of M. phoenix ( Figs.1 A-D) have axial cords slightly thinner than others ( Figs. 2 A-C, E, F). A small gradient can be observed in Figs. 2 D-F. The two types of sculpture occur in specimens from the same locality ( Figs. 2 D-F) and this may be due to intraspecific variability. Despite these differences, both forms have the same number of protoconch whorls (1.25), with a mean height of 590 µm (n = 6). The dimensions of the teleoconch are proportionally similar.

Microcancilla microscopica ( Dall, 1889) , known from Florida, USA, and western Caribbean, has a smaller protoconch (Lectotype USNM 82977, designated by Barros & Petit (2007: 99), 0.75 whorls, 560 µm wide vs. Holotype of M.phoenix , 1.25whorls, 700 µm wide),wider parietal region, and a shorter siphonal canal ( Barros & Petit,2007:figs.9-11).

Microcancilla jonasi Barros & Petit, 2007 , known from Northeast Brazil, differs by the very faint spiral sculpture with stronger axial ribs and by the flatter and narrower subsutural region resembling a crown as a result of the axial sculpture ( Barros & Petit, 2007: figs. 1-8).

Brocchinia pustulosa Verhecken, 1991 has a similar number of protoconch whorls (1.25), but the protoconch is wider (800 µm high and 900 µm wide vs. Holotype of M.phoenix , 600µm high and 700µm wide)(see Verhecken, 1991: figs. 3-4, for data of B. pustulosa ). Furthermore, B. pustulosa is larger in general, reaching 10.7 mm long, more twice the length of M. phoenix in shells with a similar number of whorls, and also has a stronger nodulation in the teleoconch ( Verhecken, 1991: figs. 1-2).

Figures

Figure 1. Microcancilla phoenix sp.nov.(A) Holotype,MNRJ60299 (2.85 mm long).(B-H) Paratype,MNRJ 28183 (4.25 mm long).(A-B) entire shell in ventral view. (C) same, lateral view. (D) same, dorsal view, white square enlarged in E. (E) Detail of teleoconch sculpture, white square enlarged in F. (F) Detail of microscopic pustules covering the shell.(G) Protoconch in frontal view.(H) Protoconch in apical view.Scale bars:A-D = 1 mm;E,G,H = 100 µm;F = 20µm.

Figure 2. Microcancilla phoenix sp.nov. (A-C) MNRJ 28191 (2.94 mm long). (D-E) MNRJ 28189 (2.72 mm, 3.07 mm and 3.39 mm, respectively).(A, B, D-F) Entire shell inventral view,white square in A enlarged in C.(B) same,lateral view.(C) Detail of teleoconch sculpture.Scale bars:A,B,D-F = 1 mm;C = 100 µm.