Mercuria maceana
Creators: name: Miller, Jonathan P.
name: Delicado, Diana
name: García-Guerrero, Fernando
name: Khalloufi, Noureddine
name: Ramos, Marian A.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Littorinimorpha
Hydrobiidae
Mercuria
Mercuria maceana

description: Mercuria maceana (Paladilhe, 1869)
Figs 15–16
Amnicola maceana Paladilhe, 1869: 103.
Mercuria maceana – Bank & Neubert 2017: 16.
Revised diagnosis
Shell ovate-conic; aperture obliquely broad ovate; periostracum yellowish to pale grey; protoconch microsculpture granulated; central radular tooth formula 3-C-3/1-1.
Type material (not examined)
Syntypes SPAIN • 1 spec. (sex unknown); Barcelona, C’an Tunis; MHNG-MOLL-105438/2 • 1 spec. (sex unknown); same collection data as for preceding; MHNL 45013950 • 1 spec. (sex unknown); same collection data as for preceding; UM.PDL.006 (Breure & Audibert 2017).
Type locality
C’an Tunis, Barcelona, Spain. The type locality of this species in the original description “récoltée à Antunez, près de Barcelone” refers to a series of local geographic names for a private property: C’an Tunis, Casa Antúnez, Camp de la Bota, Llano del Llobregat. These names have been written either conserving the original language, Catalan, sometimes using the Spanish form, or even using other local names for the same place.
Material examined
SPAIN • 30 specs; Barcelona, C’an Tunis; MNCN 15.05/7009 • 30 specs; same collection data as for preceding; MZB 77-8445, MZB 77-8107.
Description
SHELL. Ovate-conic, whorls 4–5, height 3.9–5.2 mm, width 3–3.8 mm (Fig. 15A–E); periostracum yellowish to pale grey; protoconch of 1.5 whorls, ca 350 µm wide, nucleus ca 200 µm wide (Fig. 16A); protoconch microsculpture granulated (Fig. 16B–C); teleoconch whorls convex, separated by a deep suture; body whorl large, convex, occupying about two-thirds of the total shell length; aperture obliquely broad ovate, complete; inner lip thicker than outer lip; aperture margin slightly reflexed; umbilicus narrow, not covered by the inner lip (Fig. 15A–E).
RADULA. Length intermediate, ca 800 µm long (35% of total shell length), containing about 63 rows of teeth. Central tooth formula 3-C-3/1-1, central cusp V shaped, cutting edge slightly concave (Fig. 16D). Lateral tooth formula (3)4-C-4(3), central cusp V shaped and slightly longer than the central tooth one. Inner marginal teeth with 12–14 cusps; outer marginal teeth with 12–14 cusps (Fig. 16E–F). Radular data were compiled from a dry specimen (MZB 77-8445) collected from the type locality.
Ecology and distribution
This species is only known from the type locality, C’an Tunis (Casa Antúnez), Catalonia, Spain. The type locality has likely disappeared due to extensive alterations (e.g., construction, pollution) of the area as a result of port works conducted in the Barcelona harbour and the industrial zone in the 1980s and the construction work carried out for the 1992 Olympic Games (Jordi Corbella and Francesc Uribe pers. com.). Recent surveys conducted around Barcelona did not yield live specimens.
Remarks
Mercuria maceana is only known from its type locality, which has been destroyed over the past few decades. Specimens of this species have not been found in the nearby areas, suggesting that the species is extinct (IUCN category EX). The shells and dry specimens of M. maceana deposited in the Zoological Museum of Barcelona were examined to delineate the morphological variation presented by the species and to support its recognition. Our PCA based on shell shape differentiated this species (Fig. 3). Accordingly, M. maceana differs from M. egarensis sp. nov. by its shorter and more globose or subglobose shell and is more similar to the Moroccan species M. targouasensis. Based on the characters observed on the radulae, M. maceana cannot be distinguished from M. similis or M. egarensis. We were unable to study other anatomical features due to the lack of ethanol-preserved material.
description: Published as part of Miller, Jonathan P., Delicado, Diana, García-Guerrero, Fernando, Khalloufi, Noureddine & Ramos, Marian A., 2023, Morphology and taxonomic assessment of eight genetic clades of Mercuria Boeters, 1971 (Caenogastropoda, Hydrobiidae), with the description of five new species, pp. 1-63 in European Journal of Taxonomy 866 (1) on pages 26-29, DOI: 10.5852/ejt.2023.866.2107, http://zenodo.org/record/7867353