Inella euconfio, Fernandes & Pimenta, 2019

Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2019, Taxonomic review of Inella and Strobiligera (Gastropoda: Triphoridae) from Brazil, Zootaxa 4613 (1), pp. 1-52 : 22

“ Inella ” euconfio sp. nov.

Figure 11

urn:lsid:zoobank.org:act:44EB94EF-5688-435C-A44D-A88F82BA42AB

Type material. Holotype: MNRJ 32545 . Paratypes: Brazil: Almirante Saldanha Seamount : MNRJ 33763 , RE- VIZEE-Central C1-D1 [1]. Rio de Janeiro state: MNRJ 18962 [1], MNRJ 32627 [1], 23º04ʹ14ʹʹS, 40º59ʹ31ʹʹW, 100 m, 17/xii/2004 ; MNRJ 31113 , type locality, 22/iii/2005 [2].

Other material examined. Brazil: Rio de Janeiro state: MNRJ 18705 , HAB 11-G4 [1]; IBUFRJ 19579, 22º 48ʹ S, 40 º45ʹ W, 106–110 m, 27/i/1998 [1]; MORG 52212 [4], MORG 52240 [1], MORG 52244 [1], type locality; MNRJ 30910 , type locality, 17/ix/2004 [1]; MNRJ 32401 , 23 º 15ʹ 00ʺ S, 41º 06ʹ 00ʺ W, 112 m, x/2008 [1]; MNRJ 32402 , 23 º 18ʹ 35ʺ S, 41º 14ʹ 03ʺ W, 100 m, x/2005 [1]. São Paulo state: MNRJ 32919 , 25 º 13ʹ 06ʺ S, 44º 59ʹ 31ʺ W, 160 m, viii/2008 [1].

Type locality. 23º05ʹS, 40º58ʹW, 100 m, Rio de Janeiro state, Brazil .

Etymology. The specific epithet renders a meaning in Portuguese regarding the generic name; translating to English, it would mean “in her I trust”. Epithet as a noun in apposition.

Diagnosis. Protoconch with 3.5 to 4.25 very convex whorls; median spiral cord emerges at the end of the first to the beginning of the third whorl of teleoconch; light brown to cream shell.

Description. Shell sinistral, elongated, conical, rectilinear profile, reaching 14.33 mm in length, 3.15 mm in width, length/width ratio 3.8 to 4.6. Protoconch slightly globose, subcylindrical, 0.65–0.89 mm in length, 0.57–0.66 mm in width of its last whorl; 3.5 to 4.25 very convex whorls, clear distinction between protoconch and teleoconch; initial whorl dome-shaped but slightly elevated, covered by small, spirally-disposed vesicles; remaining whorls with two spiral cords, situated at 28% and 57% of last whorl height, the abapical one becoming more prominent and assuming a keeled shape on the last whorl, the adapical one sometimes disappearing in the last whorl; numerous small axial wrinkles above the adapical cord, being nearly orthocline to very prosocline, sparsely present also below the abapical cord. Teleoconch with up to 15 whorls; two spiral cords (adapical and abapical) in the beginning, the abapical one continuous with that of the protoconch; median spiral cord emerges at the end of the first whorl to the beginning of the third whorl, reaching the same size of other cords after 2 to 2.5 whorls; on the body whorl, distance between spiral cords is 1.1 to 1.7 times the width of cords; 18 to 20 nearly orthocline to opisthocline axial ribs; rounded nodules of a medium size; distinct and well-developed suture, with a small sutural cord; moderately to weakly nodulose subperipheral cord, two weakly nodulose to wavy basal cords, the adapical one situated closer to the subperipheral cord than to the thick abapical basal cord; a very fine supranumerical cord may develop just before the peristome, between the median and the abapical spiral cords; ovate aperture, 1.00– 1.72 mm long, 0.81–1.39 mm wide, length/width ratio 1.2–1.3; anterior canal curved almost downwards, being moderately long and partly or almost closed, 0.59–0.95 mm long, 0.34–0.51 mm wide, length/width ratio 1.7–1.9; posterior canal as a small notch, 0.20–0.31 mm long, not detached from the aperture. Light brown to cream shell; coloration usually faint in worn shells.

Remarks. The most similar species to “ Inella ” euconfio sp. nov. is “ Inella ” triserialis ( Dall, 1881) sensu lectotype ( Rolán & Fernández-Garcés 2008), especially considering the early development of the median spiral cord of teleoconch ( Fig. 3 C–D). In contrast, “ I ”. triserialis has the median spiral cord already present in the beginning of the teleoconch (but emerging at the end of the first to the beginning of the third whorl in Inella euconfio sp. nov.), a different protoconch, and its bathymetry ranges from 366 m to 1472 m ( Rolán & Fernández-Garcés 2008), instead of 91 m to 160 m in “ Inella ” euconfio sp. nov. The poorly preserved condition of the lectotype of “ I ”. triserialis ( Rolán & Fernández-Garcés 2008: fig. 14C–E), without a complete base and formation of anterior and posterior canals, precludes further comparisons.

Relative to species from Brazil, “ Inella ” euconfio sp. nov. has a similar protoconch to “ I ”. faberi and “ Inella ” sp. 2, but in these species the median spiral cord usually emerges at the fifth or sixth whorl of teleoconch, instead of the first to the beginning of the third whorl in “ Inella ” euconfio sp. nov. ( Fig. 11 E–F). Also, the three main spiral cords on the teleoconch of “ Inella ” euconfio sp. nov. have similar thickness, although the adapical cord of “ I ”. faberi and “ Inella ” sp. 2 is more prominent than other cords at the body whorl.

“ Inella ” euconfio sp. nov. has a similar teleoconch to Eutriphora auffenbergi Rolán & Lee, 2008 , a species from the southeastern U.S.A. ( Rolán & Fernández-Garcés 2008; Lee 2009), including the large shell size attained by both species (14.33 mm in “ Inella ” euconfio sp. nov., 21.8 mm in E. auffenbergi ). However, the multispiral protoconch of E. auffenbergi, indicative of planktotrophic development, is easily distinguishable from the lecithotrophic mode (but multi-whorled protoconch, up to 4.25 whorls) in “ Inella ” euconfio sp. nov. (Fig. 11I). Geographical distribution. Brazil: Almirante Saldanha Seamount, Rio de Janeiro and São Paulo. Bathymetric distribution. 91–160 m.

Figures

FIGURE 3. Type material of some species of Inella and Strobiligera. A–B. “Inella” intermedia (Dall, 1881), lectotype MCZ 7386 (A), non-type MCZ 7385 (B). C–D. “Inella” triserialis (Dall, 1881), paralectotypes MCZ 7384 (C) and MCZ 7382 (D). E–F. “Inella” faberi Rolán & Fernández-Garcés, 2008, holotype FLMNH 291343 (E), paratype FLMNH 419388 (F). G. “Inella” differens Rolán & Lee, 2008, holotype FLMNH 419184. H–I. “Inella” undebermuda Rolán & Lee, 2008, holotype FLMNH 419181 (H), paratype USNM 1112657 (I). J. “Inella” longissima (Dall, 1881), lectotype MCZ 7381. K–L. “Inella” harryleei Rolán & Fernández-Garcés, 2008, holotype FLMNH 419182 (K), paratype FLMNH 158178 (L). M. Strobiligera sentoma (Dall, 1927), lectotype USNM 108072. N. “Inella” pseudolongissima Rolán & Fernández-Garcés, 2008, paratype FLMNH 171183. O–P. Inella pseudotorticula Rolán & Lee, 2008, holotype FLMNH 419191 (O), paratype USNM 1112658 (P). Q. Strobiligera pompona (Dall, 1927), lectotype USNM 108339. R. Strobiligera compsa (Dall, 1927), lectotype USNM 333518. S–T. Strobiligera gaesona (Dall, 1927), lectotype and paralectotype USNM 108341. U–V. Strobiligera dinea (Dall, 1927), lectotype and paralectotype USNM 333517. W. Inella colon (Dall, 1881), paralectotype MCZ 7387. X. Strobiligera enopla (Dall, 1927), lectotype USNM 108074.Y. Inella apexbilirata Rolán & Fernández-Garcés, 2008, holotypeANSP 367841, credits of image to Paul Callomon. Scale bars: A, H–R, 5 mm; B–G, S–Y, 1 mm.

FIGURE 11. “Inella” euconfio sp. nov. A. MNRJ 32545, holotype, 7.96 mm. B. MNRJ 32627, paratype, 14.33 mm. C. MNRJ 33763, paratype, 6.83 mm. D–E. MNRJ 31113, paratype, 7.93 mm. F, I–K: MNRJ 18692, shell not illustrated (K, detail of first protoconch whorl). G–H: same shell as D. Scale bars: A–E, 1 mm; F–H, 500 µm; I–J, 100 µm; K, 50 µm.