Monophorus caracca ( Dall, 1927 ) Fernandes & Pimenta, 2020

Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2020, Unraveling one of the ‘ Big Five’: update of the taxonomy of Triphoridae (Gastropoda, Triphoroidea) from Brazil, European Journal of Taxonomy 665 (665), pp. 1-170 : 25-27

Monophorus caracca ( Dall, 1927) comb. nov.

Figs 10 , 23N , 57

Triphora (Biforina) caracca Dall, 1927: 92 .

“ Triphora ” caracca – Rolán & Fernández-Garcés 2008: 140, fig. 24a–e.

Material examined

Lectotype

UNITED STATES OF AMERICA – off Georgia • 30º43′59″ N, 79º25′59″ W; depth 805 m; 1 Apr. 1885; R/V Albatross leg.; USNM 108343 . Two paralectotypes are also found under the same lot number.

Other material

BRAZIL – off Espírito Santo • 4 specs; MD55 st. 42-DC75; MNHN *.

Description

Shell sinistral, elongated, conical, rectilinear profile, the better-preserved shell is 5.7 mm long, 1.5 mm wide, although complete adult shells may be much larger. Protoconch multispiral but partially broken; penultimate whorl with cruciform granules spirally disposed; last whorl with two spiral cords, situated at ~31% and ~62% of whorl height, crossed by weak axial ribs, despite a smooth spiral zone (i.e., without axial sculpture) just above the adapical spiral cord; prosocline (below suture) to opisthocline (below adapical cord) axial ribs. Teleoconch with up to 14 whorls; two spiral cords (adapical and abapical) at beginning, abapical one continuous to that of protoconch; median spiral cord emerges very weakly in sixth/seventh whorl, much close to adapical cord, gradually strengthening but not reaching same size of other cords even after eight whorls; in late whorls, the spiral cords are 2.0–3.5 × as wide as distance between them; 16 opisthocline axial ribs; rounded to elliptical nodules of medium size, pointed profile, keeled-shaped, especially in abapical cord; median spiral cord initially wavy, acquiring nodules after many whorls; distinct but somewhat shallow suture, with small sutural cord that gradually strengthens and becomes thick in late whorls; additional spiral cord emerges in very late whorls, immediately above adapical spiral cord; thick, smooth subperipheral cord, one thin and smooth basal cord much close to subperipheral cord; base and canals not formed or considerably damaged. Brown protoconch, white teleoconch.

Remarks

The present species shows a late median spiral cord of the teleoconch ( Fig. 10J ), a protoconch with cruciform granules and a smooth spiral zone ( Fig. 10G ), features which are also observed in Monophorus ( Marshall 1983) . Monophorus caracca ( Dall, 1927) comb. nov. was described from the deep sea off Georgia ( USA). After comparisons with the type material ( Fig. 10A ), the single minor difference being the median spiral cord emerging in the sixth/seventh whorl of the teleoconch in a Brazilian shell, but it emerging discreetly in the eighth whorl of the lectotype, being properly detected only in the tenth whorl ( Rolán & Fernández-Garcés 2008). In addition, the bathymetric record of the type locality is deeper than seen in Brazil (805 m and 295 m, respectively).

Agreeing with the initial assignment of this species to the subgenus Biforina (currently a synonym of Monophorus ) by Dall (1927), this species is now regarded as belonging to Monophorus . Although Dall (1927) did not explain the etymology of the specific name, ‘ caracca ’ is a word in Italian which refers to large sailboats/ships used during the Great Navigations; because it is a noun, the ending remains unaltered after the new generic allocation ( ICZN 1999: article 31.2).

Geographical records

USA: off Georgia (type locality). Brazil: off Espírito Santo (this study).

Bathymetric distribution

Depth: 295 m (this study) to 805 m (type locality).

Figures

Fig. 10. Monophorus caracca (Dall, 1927) comb. nov. A. USNM 108343, lectotype, 7.1 mm. B–E. MNHN*, 4.42 mm, 6.84 mm, 4.50 mm and 5.74 mm, respectively. F–J. Same shell as E. Scale bars: A–F = 1 mm; G = 100 µm; H = 20 µm; I = 250 µm; J = 500 µm.

Fig. 23. Triphoridae from Brazil (2). A. “Inella” sp. 4. B. Iniforis carmelae Rolán & Fernández- Garcés, 1993. C. Iniforis pseudothomae Rolán & Fernández-Garcés, 1993. D. Isotriphora leo sp. nov. E. Isotriphora onca Fernandes, Pimenta & Leal, 2013. F. Isotriphora tigrina Fernandes, Pimenta & Leal, 2013. G. Isotriphora tricingulata Rolán & Fernández-Garcés, 2015. H. Isotriphora uncia sp. nov. I. Isotriphora sp. 1. J. Latitriphora albida (A. Adams, 1854). K. Marshallora sp. L. Marshallora ostenta Rolán & Fernández-Garcés, 2008. M. Marshallora sp. 1. N. Monophorus caracca (Dall, 1927) comb. nov. O. Monophorus olivaceus (Dall, 1889). P. Monophorus verecundus sp. nov. Q. Nanaphora leei Fernandes & Pimenta, 2015. R. Nanaphora verbernei (Moolenbeek & Faber, 1989). S. Nanaphora sp. 1. Scale bars: 1 mm.

Fig. 57. Distribution map of Monophorus caracca (Dall, 1927) comb. nov. (red circle = type locality; black circle = additional locality) and Monophorus verecundus sp. nov. (brown circle = type locality; gray circles = additional localities).