Puncturella agger Watson 1883
Creators: name: Gofas, Serge
name: Luque, Ángel A.
name: Oliver, Joan Daniel
name: Templado, José
name: Serrano, Alberto
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Lepetellida
Fissurellidae
Puncturella
Puncturella agger

description: Puncturella agger Watson, 1883
Fig. 5A‒N
Puncturella agger Watson, 1883: 32.
Puncturella agger – Watson 1886: 40, pl. 4 fig. 6.
Puncturella profundi (Jeffreys, 1877) – Rolán Mosquera & Pérez-Gándaras 1981: 6, pl. 1 fig. 4. — Rolán Mosquera 1983: 68.
Rimula granulata Seguenza, 1863 – Beck et al. 2006: 41. — Hoffman et al. 2011a: 90, pl. 108 figs 39‒44.
Cranopsis sp. – Corral Prado 2006: 27‒30.
Cranopsis agger (Watson, 1883) – Barrio González 2015: 109‒123, figs 32‒34.
Type material
Syntype
VIRGIN ISLANDS • 1 sh (Fig. 5J–L); off St. Thomas, north of Culebra Island; 18°38′30″ N, 65°5′30″ W; 390 fathoms; 25 Mar. 1863; Challenger expedition, Station 24, coral-mud; NHMUK 1887.2.9.130.
Material examined
GALICIA BANK • 2 sh; 42°52′ N, 11°51′ W; 985‒1000 m; 20 Oct. 1987; SEAMOUNT 1 DW116; MNHN • 3 spm; 42°49.13′ N, 11°46.59′ W; 903 m; 4 Aug. 2011; BANGAL 0711 GOC6; MNCN • 1 sh; 42°41.94′ N, 11°40.58′ W; 744 m; 31 Jul. 2011; BANGAL 0711 V4; MNCN • 1 sh; Galicia Bank (no more details); 590‒900 m; 1980‒1981; G. Pérez-Gándaras, Instituto de Investigaciones Pesqueras de Vigo-CSIC leg.; CER-MHNS.
Description (based on material examined from GB)
Shell small (length 4.0 mm, width 2.9 mm, height 3.9 mm), with an oval outline in apertural view, in lateral view with a conical profile, the apex located in the posterior ¼ and in the upper ⅓ of the shell, curved towards the ventral side. Protoconch of one whorl, rounded, skewed to the right side, with a diameter ca 245 μm (Fig. 5E). Selenizone small but well marked, narrower than the foramen, bordered by a smooth and slightly raised rim. Foramen elongate, narrowing anteriorly to a sharp point, located dorsally in the highest part of the shell, bordered on each side by a flange that continues that of the selenizone; width of the foramen 9% of the width of the shell; length 30% of the length of the shell. In front of the foramen, there is a double rib along which the two halves of the shell meet. Sculpture almost absent in the initial coiled part, then mainly constituted by small pustules, aligned along a median thread to form radial cords (Fig. 5F). The width of the interspaces between radial cords is equivalent to or somewhat greater than the thickness of the pustules, and the interval between pustules along a cord is less than the diameter of the pustules. In the abapical half of the shell, appear additional radial cords that grow rapidly in thickness until the primary cords are matched. There are around 80‒90 radial cords reaching the growth edge of the shell, of which one-third was added in the abapical half. The pustules are also connected by fine, irregular commarginal lamellae. Aperture oval, contained in a plane, with its edge denticulated by the termination of the cords. Inner surface smooth, shiny, with a groove running from the foramen to the anterior edge. Large internal septum (one third of the total length of the shell), with sharp and almost straight anterior edge, concealing more than half of the foramen in apertural view.
Distribution
The type locality of Puncturella agger is Challenger station 24, off north of Culebra Island, Puerto Rico. It was subsequently recorded from Florida, Cuba and Mexico by Pérez Farfante (1947). Living specimens and shells are known from NW Galicia and Galicia Bank, shells only from Meteor, Hyères, Irving, Plato, Atlantis and Josephine seamounts (Corral Prado 2006, as Cranopsis sp.; Barrio González 2015, as Cranopsis agger (Watson, 1883)), and shells recorded as Rimula granulata Seguenza, 1863, from Ampère, Seine and Sedlo seamounts (Beck et al. 2006) and Rockall Bank (Hoffman et al. 2011a), see under remarks. The species has therefore an amphiatlantic distribution.
Remarks
This species has been reported from different locations in the northeast Atlantic with names which we consider wrong. Rolán Mosquera & Pérez-Gándaras (1981: 6, pl. 1 fig. 4) and Rolán Mosquera (1983: 68) recorded and illustrated for the first time one specimen from the Galicia Bank, misidentified as Puncturella profundi Jeffreys, 1877, which is a different species currently named Profundisepta profundi (Jeffreys, 1877), (see Fig. 6E–G herein). The specimen figured in the aforementioned papers is illustrated again here (Fig. 5M–N).
The shell figured by Micali & Villari (1989: figs 1‒4) as Rimula granulata Seguenza, 1863, from the Pleistocene of Salice (Sicily) is somewhat similar to P. agger, but clearly differs in having an extremely inflated profile, with an apex much more anterior and much more curved towards the ventral edge so as to be situated near the half of the total height of the shell (in the upper third in Puncturella agger). The sculpture of this fossil species is also different, with the radial rows of tubercles all of similar size and thicker than the spaces between rows. An old shell, possibly subfossil, collected from the Galicia Bank (Fig. 4K‒L) could represent the real Puncturella granulata, since it agrees in profile and sculpture with the original description and illustration of Rimula granulata by Seguenza (1863: 88, figs 6, 6a). Watson (1883: 31) reported and described a specimen of “ Puncturella (Cranopsis) granulata, Seg. [tuberculata n. sp.]”, also collected in the type locality of Puncturella agger (Challenger Sta. 24). However, it is not clear whether this identification is correct since Watson’s (1886: 46, pl. 4 fig. 5) illustration is a copy of Seguenza’s (1863: fig. 6) and he described his specimen as “peculiarly long and narrow” which does not fit the original description. This identification was nevertheless assumed by Pérez Farfante (1947: 125‒126, pl. 54 figs 4‒7) who also considered that Puncturella watsoni Dall, 1889 was the same as P. (C.) granulata sensu Watson (1883, 1886). Puncturella watsoni is also very close to the Western Atlantic Puncturella larva Dall, 1927 (see Pérez Farfante 1947).
Further specimens of Puncturella agger from SEAMOUNT 1 DW116 were recorded in Eva Corral’s unpublished undergraduate project (Corral Prado 2006) as Cranopsis sp. Later, Lucia Barrio in her PhD Thesis (Barrio González 2015) described and illustrated as Cranopsis agger (Watson, 1883) a large amount of material (32 specimens and 362 shells) collected in several cruises from different localities of NW Galicia and several NE Atlantic seamounts (see under distribution).
Puncturella fornicata Locard, 1898, a valid species never reported since its original description from off Western Sahara, 782 m (Locard 1898: 78‒79, pl. 5 figs 1‒3), is somewhat similar to P. granulata in profile but with definite radial ribs as in P. asturiana and P. noachina.
None of the eight western Atlantic species of Cranopsis described and illustrated by Simone & Cunha (2014) is identical to Puncturella agger. Cranopsis canopa Simone & Cunha, 2014 is somewhat similar in profile and in having a relatively small septum, but it differs from P. agger in having fewer and broader axial ribs (46 versus up to 90 in P. agger), uniform axial ribs (P. agger usually has larger and smaller ribs intercalated), and the ventro-anterior edge of the septum concave, while in P. agger it is convex.
description: Published as part of Gofas, Serge, Luque, Ángel A., Oliver, Joan Daniel, Templado, José & Serrano, Alberto, 2021, The Mollusca of Galicia Bank (NE Atlantic Ocean), pp. 1-114 in European Journal of Taxonomy 785 (1) on pages 32-36, DOI: 10.5852/ejt.2021.785.1605, http://zenodo.org/record/5798418