Inella

Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2019, Taxonomic review of Inella and Strobiligera (Gastropoda: Triphoridae) from Brazil, Zootaxa 4613 (1), pp. 1-52 : 27-29

“ Inella ” faceta sp. nov.

Figure 14

urn:lsid:zoobank.org:act:ED2D1925-84E6-405E-93BA-2AD917BEE15E

Type material. Holotype: MNRJ 18712 . Paratypes: Brazil: Bahia state: MNRJ 32913 , 13 º 25ʹ 43ʺ S, 38º 49ʹ 30ʺ W, 32 m, v/2007 [1]. Rio de Janeiro state: MNRJ 18641 , HAB 16-G3 [1]; MNRJ 32062 , 23 º 13ʹ 30ʺ S, 41º 21ʹ 00ʺ W, 93 m, x/2008 [2]; IBUFRJ 2319, 23º 42ʹ 12ʺ S, 43º 01ʹ 06ʺ W, 129 m, 28/iii/1983 [1].

Other material examined. Brazil: Espírito Santo state: IBUFRJ 19503 [1], IBUFRJ 19602 [3], REVIZEE- Central C 1-VV38 ; MORG 52259 , REVIZEE-Central C1-VV22 [1] . Rio de Janeiro state: MORG 39415 , Campos Basin [2] ; MNRJ 18713 , HAB 13-I4 [1]; MNRJ 32365 , 22 º 42ʹ S, 40º 40ʹ W, 110–120 m, ix/2004 [1]; MNRJ 31120 , 22 º 42ʹ S, 40º 40ʹ W, 110–120 m, xi/2007 [1]; IBUFRJ 11697 [5], IBUFRJ 11700 [1], IBUFRJ 19578 [3], 22º 48ʹ S, 40º 45ʹ W, 106–110 m, 27/i/1998; MNRJ 32045 , 23 º 03ʹ 18ʺ S, 41º 02ʹ 06ʺ W, 97 m, x/2008 [1]; MORG 52213 , 23 º 04ʹ 14ʺ S, 40º 59ʹ 31ʺ W, 100 m, 17/xii/2004 [4]; MNRJ 31114 , 23 º 04ʹ 14ʺ S, 40º 59ʹ 31ʺ W, 100 m, iii/2005 [1]; MNRJ 32398 , 23 º 05ʹ S, 40º 59ʹ W, 100 m, v/2009 [1]; MNRJ 32543 [3] , MORG 52235 [1] , MORG 52243 [2], 23º 05ʹ S, 40º 58ʹ W, 100 m ; MNRJ 32070 , 23 º 09ʹ 00ʺ S, 41º 02ʹ 06ʺ W, 100 m, x/2008 [1]; MNRJ 60196 , PADCT sta. 6627 [1] . São Paulo state: MNRJ 32920 , 25 º 13ʹ 06ʺ S, 44º 59ʹ 31ʺ W, 160 m, viii/2008 [1].

Type locality. HAB 13-H5, 21º 42ʹ 33ʺ S, 40º 09ʹ 06ʺ W, 147 m, Rio de Janeiro state, Brazil .

Etymology. facetus, L. = fine, elegant. It alludes to the refined shell sculpture and color pattern of this species.

Diagnosis. Golden protoconch, with two spiral cords very close to each other, the abapical one much more prominent; adapical spiral cord of teleoconch with orange nodules alternating with white nodules; median spiral cord often emerges on the sixth whorl of the teleoconch, usually reaching the same size of the abapical cord after five whorls.

Description. Shell sinistral, elongated, conical, rectilinear profile, reaching 8.95 mm in length, 2.07 mm in width, length/width ratio 3.9 to 4.3. Protoconch somewhat tumid, subcylindrical, 0.59–0.84 mm in length, 0.58–0.65 mm in width in its last whorl; 3.25 to 4 very convex whorls, clear distinction between protoconch and teleoconch; initial whorl dome-shaped, covered by several vesicles and spirally disposed granules; remaining whorls initially with two spiral cords, situated at 41% and 54–67% of penultimate whorl height, the abapical one much more prominent and gradually assuming a very keeled shape (barely resulting in a pagoda-shape to each protoconch whorl), the adapical one gradually diminishing and becoming much closer to the abapical cord, disappearing just before the transition to the teleoconch or even earlier; small, numerous faint axial riblets, more evident above the adapical cord, being nearly orthocline to much prosocline. Teleoconch with up to 12 whorls; two spiral cords (adapical and abapical) in the beginning, the abapical one continuous with that of the protoconch; median spiral cord emerges narrowly at the end of the fifth to the beginning of the seventh whorl, reaching the same size of the abapical cord (the adapical one is more prominent, especially in late whorls) after 4.5 to 5.5 whorls; on the body whorl, distance between spiral cords is 0.9 to 1.2 times the width of cords; 18 to 21 strongly opisthocline axial ribs; rounded (especially the adapical cord) to slightly elliptical (median and abapical cords) nodules of a medium to moderately large size; distinct and well-developed suture, with a small sutural cord; weakly nodulose to wavy subperipheral cord, one narrow, slightly wavy basal cord, besides a smooth thickening below it, directed downwards, not developing in a true abapical basal cord; no supranumerical cords; ovate aperture, 0.98–1.22 mm long, 0.87–1.03 mm wide, length/ width ratio 1.1–1.2; anterior canal curved almost downwards, moderately long, partly or entirely closed, 0.58–0.69 mm long, 0.37–0.43 mm wide, length/width ratio 1.5–1.6; posterior canal a deep, wide sinus, 0.16–0.19 mm long, not detached from the aperture. Protoconch golden; cream/whitish background of teleoconch, the adapical spiral cord irregularly tinted with one or two orange nodules usually alternating with one or two (hardly ever three) white nodules, with the orange patches occasionally reaching the median spiral cord; light brown/orange base.

Remarks. This is a fairly common species in Campos Basin, southeastern Brazil, possessing very distinct features, like the protoconch sculpture with two close spiral cords ( Fig. 14 I–K), the gradual development of the median spiral cord of the teleoconch (reaching the same size of the abapical cord about five whorls after its emergence) and the notable color pattern of the adapical spiral cord of teleoconch ( Fig. 14 A–D). The teleoconch of the western Atlantic species Monophorus olivaceus ( Dall, 1889) superficially resembles that of “ Inella ” faceta sp. nov., especially in the irregular brown/orange blotches alternating with white nodules in the adapical spiral cord.

Geographical distribution. Brazil: Bahia to São Paulo.

Bathymetric distribution. 32–160 m.

Figures

FIGURE 14. “Inella” faceta sp. nov. A. MNRJ 18712, holotype, 8.78 mm. B. MNRJ 32062, paratype, 7.34 mm. C. MNRJ 32913, paratype, 7.72 mm. D. IBUFRJ 2319, paratype, 7.88 mm. E–J: holotype. K–M: same shell as B. Scale bars: A–E, 1 mm; F–H, 500 µm; I, L, 50 µm; J–K, M, 100 µm.