Triphora charybdis sp. nov.

(Figure 7 C–K)

Type material. Holotype: MNRJ 18620. Paratypes: Brazil: Rio de Janeiro state: MNRJ 31107, 22º42’S, 40º40’W, xi/2007 [1]; MNRJ 32067, 22º42’S, 40º40’W, x/2007 [1]; MNRJ 32404, 22º42’S, 40º40’W, viii/2002 [1]; MNRJ 33527, type locality [1]; MNRJ 32549, 23º05’S, 40º58’W, 100 m [2]; MORG 52207 [1], MORG 52238 [1]: 23º05’S, 40º58’W, 100 m.

Other material examined. Brazil: Amapá state: MNRJ 33392, 04º27’54”N, 49º58’05”W, 160 m, 13/x/2000 [18]. Rio de Janeiro state: MNRJ 32351, 22º20’29”S, 40º11’41” W, xii/2004 [2]; MNRJ 19480, 22º42’S, 40º40’W, 110 m, 11/iv/2003 [1]; MNRJ 30869, 22º42’S, 40º40’W, 110 m, 19/ix/2003 [2]; IBUFRJ 19563, 22º48’S, 40º45’W, 110 m, iv/1998 [7]; IBUFRJ 19576, 22º48’S, 40º45’W, 110 m, 27/i/1998 [2]; IBUFRJ 19593, REVIZEE C1-D3 [1]; MORG 48290, 23º05’S, 40º58’W, 100 m [1]; MORG 52247, 23º05’S, 40º58’W, 100 m [1]. Santa Catarina state: MNRJ 32071, 26º38’45”S, 46º51’54”W, 153 m, ii/2004 [8]; MNRJ 32622, 26º38’51”S, 46º52’30”W, 150 m, 28/i/2005 [3]; MORG 50071, off Itajaí, 28/i/2005 [4].

Material examined of Triphora cf. lilacina (Dall, 1889) in Rolán & Fernández-Garcés (2008): FLMNH 129846 [2]; FLMNH 154900 [2]; FLMNH 238675 [5]; FLMNH 279375 [1].

Type locality. Station HAB 16-B4 of Project Habitats: 23º10’01”S, 41º03’13”W, 107 m, Rio de Janeiro state, Brazil.

Etymology. The specific name refers to the sea monster Charybdis, from Greek Mythology. Epithet as a noun in apposition.

Diagnosis. Median spiral cord usually emerges on seventh teleoconch whorl, reaching same size of abapical cord after about five whorls; white adapical spiral cord, brown abapical cord, median cord initially white and later becoming brown or being brown from its emergence; long anterior canal, almost closed, directed downward.

Description. Shell sinistral, elongated, conical-fusiform, rectilinear profile, reaching 8.53 mm in length, 1.97 mm in width. Brown protoconch; teleoconch with white adapical spiral cord, brown to orange-brownish abapical cord, median cord initially white but later becoming brown/orange-brownish or brown/orange-brownish since its emergence; nodules lighter in color than inter-nodular spaces in all spiral cords; orange-brownish base. Protoconch conical, 0.54–0.60 mm in length, 0.39–0.42 mm in width, with 5 to 5.5 convex whorls; embryonic shell domeshaped, covered by rounded granules overall; larval shell with one spiral cord (abapical) at its beginning, the adapical cord emerging after one whorl, but disappearing just before the transition to teleoconch; about 28 almost rectilinear to slightly sigmoid axial ribs. Teleoconch with up to 14 whorls; two spiral cords (adapical and abapical) on the first whorl, abapical one continuous with that of protoconch; median spiral cord emerges between end of sixth and beginning of eighth whorl, reaching same size of abapical cord (adapical one slightly more pronounced than others) after 4.5 to six whorls; 20 to 21 opisthocline axial ribs; rounded nodules of medium size; distinct but little developed suture, with a small sutural cord; narrow and weakly nodulose to wavy subperipheral and adapical basal cords, slightly wavy to smooth abapical basal cord; two supranumerical cords may develop, one between median and abapical spiral cords, the other between abapical and subperipheral cords; aperture ovate; long anterior canal, almost closed, directed downward; posterior canal as a notch, not detached from aperture.

Remarks. Shells of Triphora charybdis sp. nov. from Amapá (northern Brazil) and Santa Catarina (southern Brazil) are much worn, although their identification as this species is unambiguous. In a certain way, they resemble sub-fossil material, almost losing the original coloration, indicating that this species may have had a wider distribution in the past.

Triphora charybdis is similar to the morphotype Triphora cf. lilacina (Dall, 1889) in Rolán & Fernández-Garcés (2008), also illustrated in the present study (Fig. 7 B). The protoconch sculpture, the coloration pattern of the teleoconch and the whorl in which the median spiral cord emerges are very similar in both. In contrast, T. charybdis has a later strenghtening of the median spiral cord (reaching the same size of the abapical cord after about five whorls, Fig. 7 F; after ~2.5 whorls in T. cf. lilacina, Fig. 7 B), slightly longer anterior canal directed downward (Fig. 7 H), more heterogeneous coloration between adapical (white) and abapical (brown) spiral cords on the teleoconch (the distinction of coloration is not so evident in most shells of T. cf. lilacina - Fig. 7 B), narrower and less nodulose subperipheral cord (Fig. 7 H), in addition to a more rectilinear shell profile (but slightly curvilinear profile in T. cf. lilacina). The shell of Triphora lilacina (Dall, 1889), whose lectotype is illustrated herein (Fig. 7A) and in Rolán & Fernández-Garcés (2008), has a curvilinear profile, lilac coloration, and median spiral cord emerging only in the eleventh whorl (Rolán & Fernández-Garcés 2008), thus being greatly differentiated from T. charybdis .

Shells of T. charybdis with damaged or incomplete base (without the distinct anterior canal) and with few teleoconch whorls (precluding the late development of the median spiral cord) can be mistaken for other species from the western Atlantic having a white adapical cord and a brown abapical cord. Triphora ellyae De Jong & Coomans, 1988 is easily distinguished by its smaller size, curvilinear-ovoid shell shape, and smooth subperipheral cord. Triphora atlantica (Smith, 1890) has two or three white initial teleoconch whorls, a thicker and more nodulose subperipheral cord, and larval shell with only one spiral cord (the abapical) on two whorls, but on one whorl in T. charybdis (Fig. 7 I). In Triphora elvirae De Jong & Coomans, 1988 and Eutriphora bermudensis (Bartsch, 1911), the median spiral cord is always white, but in T. charybdis it acquires a brown coloration after its emergence (Fig. 7 C-D).

Geographic distribution. Brazil: Amapá [subfossil?], Rio de Janeiro and Santa Catarina [subfossil?].

Bathymetric distribution. 80 to 160 m.