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This paper describes rare Cardiomya species from Brazil which have been hitherto misidentified as Cardiomya cleryana (d’Orbigny, 1842) in literature or museum collections. Cardiomya minerva sp. nov. is proposed as new species and is characterized by its quadrangular shell, short and truncated rostrum, and external ornamentation composed of six radial ribs on the posterior half of the shell flank. Cardiomya striolata (Locard, 1897) described from the Mediterranean Sea and northwestern Atlantic Ocean, is reported from Brazil for the first time; although previously regarded as a junior synonym of Cardiomya costellata (Deshayes, 1835), it is herein considered as a full species and redescribed. This species is characterized by its trapezoidal shell flank, elongated rostrum, tapering towards the tip, and external ornamentation composed of 18–53 radial ribs, the 3–4 posterior ones being the strongest and more widely spaced. Other three previously unknown species are illustrated but not formally named due to the lack of well-preserved articulated shells.
The subfamily Sepiolinae (Mollusca: Cephalopoda: Sepiolidae), currently containing the genera Sepiola Leach, 1817, Euprymna Steenstrup, 1887, Inioteuthis Verrill, 1881, Rondeletiola Naef, 1921 and Sepietta Naef, 1912, is characterized by the hectocotylization of the left dorsal arm, i.e., its transformation into a copulatory organ thanks to modifications of sucker/pedicel elements. The hectocotylus morphology varies to a great extent across genera and species. In particular, one to several pedicels in its proximal third lose their sucker and become highly and diversely modified in shape to constitute a copulatory apparatus. An evolutionary gradient was observed in the copulatory apparatus morphology, from the simple modification into a papilla of just one pedicel from the third element of the ventral sucker row (some nominal species of Euprymna) to a quite complex structure involving several variously modified pedicels from both the ventral and dorsal sucker rows (Inioteuthis). In some species, elements in the distal portion of the hectocotylus may also be highly modified, such as the columnar suckers in Euprymna. The hectocotylian diversity allows to distinguish nine groups of species that do not match the current generic subdivision of Sepiolinae. Additional morphological characters (number of sucker rows on arms, female bursa copulatrix, occurrence and shape of visceral light organs, etc.) corroborate the subdivision of Sepiolinae into nine subtaxa, i.e., genera. Accordingly, a cladogram is drawn to describe the possible phylogenetic relationships among the nine clades. To comply with these results, all current genera are redefined and four new genera are described, namely Adinaefiola gen. nov., Boletzkyola gen. nov., Eumandya gen. nov. and Lusepiola gen. nov.
The present study aims to fulfill the gap of taxonomic knowledge on Triphoridae from Brazil. We describe five new species (Isotriphora uncia sp. nov., Isotriphora leo sp. nov., Monophorus verecundus sp. nov., Sagenotriphora albocaput sp. nov., Similiphora lucida sp. nov.), report five species previously known only from the Caribbean and related areas (Cheirodonta dupliniana (Olsson, 1916), Eutriphora auffenbergi Rolán & Lee, 2008, Isotriphora tricingulata Rolán & Fernández-Garcés, 2015, Marshallora ostenta Rolán & Fernández-Garcés, 2008, Monophorus caracca (Dall, 1927) comb. nov.) and describe six morphotypes at the generic level (Isotriphora sp. 1, Marshallora sp. 1, Nanaphora sp. 1, Sagenotriphora sp. 1, Sagenotriphora sp. 2, Similiphora sp. 1). Remarks are made to some species previously recorded from Brazil, including the invalidation of records, problems of generic allocation and geographical range extensions. Maps of the geographical distribution are provided for the 65 currently recognized species of Triphoridae from Brazil. Of these, 31 species are endemic to Brazil and 58 inhabit the continental shelf vs only seven from the continental slope. A distinct geographical zone occurs in southeastern Brazil. A few species occur exclusively near the mouth of the Amazon River, whereas others inhabit a local biogenic reef, possibly serving as a biogeographical corridor that connects western Atlantic populations. Species of Isotriphora from Brazil are particularly common around oceanic islands, probably due to adopting intracapsular metamorphosis, which may have evolved in more than one evolutionary event.