Polyschides quadridentatum ( Dall, 1881 )

Simone, Luiz Ricardo L., 2024, New species, misidentifications and problematic taxonomy of some Atlantic South American marine mollusks: a review, Papéis Avulsos de Zoologia 64, pp. 1-104 : 98-100

Polyschides quadridentatum ( Dall, 1881) revalidated, new combination

( Fig. 65 H-N)

Siphonodentalium quadridentatum Dall, 1881: 36 ; Steiner & Kabat, 2004: 636, 655.

Cadulus quadridentatus : Dall, 1889: 428-429 (pl. 24, fig. 5); Henderson, 1920: 97-99; Morretes, 1949: 52; Davis, 1968: 135-138 (fig. 1); Abbott, 1974: 389 (fig. 4545); Penna-Neme, 1974: 115.

Cadulus tetraschistus quadridentatus : Pilsbry & Sharp, 1898: 149 (pl. 23, fig. 7; pl. 28, figs. 1-5).

Cadulus tetraschistus : Penna-Neme, 1974: 114; Rios, 1975: 182 (pl. 58 fig. 889), 1985: 202 (pl. 73, fig. 1034); Scarabino, 1980: 11-12 (fig. 1) (non Watson, 1879).

stitut Sektion Malakologie. For the photo of Fissurella clenchi holotype and paratypes, and of the types of Fusinus brasiliensis , I am grateful to MCZ team, particularly Jennifer Trimble (Curatorial Assistant in IZ/Malacology), Melissa Merkel, Gonzalo Giribet and Adam J. Baldinger. For photos of live Pseudocyphoma intermedium I am grateful to Paulo Marcio S. Costa, Rio de Janeiro, and José Leal, BMSM. For photos of live Cyphoma gibbosum , I am grateful to Marcus and José Coltro, Femorale, and to Rick Stuart-Smith,Reef LifeSurveyhttps://reeflifesurvey.com.Thegastropodmaterialcollectedinthe MD 55 expedition in 1987, here studied, belongs to the MNHN, Paris, and a minor part was donated to MZSP by Philippe Bouchet; the collectors in that expedition were Bouchet,Leal and Métivier;the bivalve material belonged to Santa Úrsula University, Rio de Janeiro,and was donated to MZUSP,but part of it was also shared with NMHN. Photos of Dall types deposited in USNM were kindly sent by Ellen Strong,and are credited to the Department of Invertebrate Zoology, NMNH( USNM),Smithsonian Institution,particularlyYolandaVillacampa. The author gratefully acknowledge support by the Centro para Documentação da Biodiversidade,FFCLRP,University of São Paulo,Ribeirão Preto, Brazil for the tomography examinations. For Lara Guimarães. MZSP, for SEM examination of radulae.To William Lyons for the talking about Brazilian fasciolariid taxonomy.To Carlos E. Belz,Fabrizio M. Machado,Marcelo V. Fukuda and Airton Cruz for valuable comments on the manuscript in review process.

Polyschides tetraschistus : Días & Puyana, 1994: 257-258 (fig. 1048); Rios, 1994: 310 (pl. 107, fig. 1522), 2009: 453 (fig. 1281); Redfern, 2001: 191 (pl. 76 fig. 785); Absalão & Paula , 2004: 1-11 (fig. 1C); Steiner & Kabat, 2004: 557, 601, 606, 655, 656; Absalão et al., 2005: 175-178 (fig. 4); Caetano & Absalão, 2005: 1-8 (figs. 5-8); Caetano et al., 2006: 3 , 32-33 (figs. 64, 65) (non Watson, 1879).

Type locality: West coast of Florida, 30 fms.

Remarks: In the original description, Dall (1881: 36) already highlighted the distinctions between his newly described species and the previously known P. tetraschistus , particularly in terms of size and degree of obesity. These differences, along with other subtle details, prompted him to distinguish the Fernando de Noronha sample from his Floridian one.Despite these disparities, Pilsbry & Sharp (1898) remained unconvinced and considered every relatively slender,4-lobed posterior end species in the Western Atlantic as a single species ( tetraschistus , quadridentatus , and incisus ). This concept has been followed ever since, e.g., Penna-Neme (1974), Scarabino (1980).

However, subsequent collections revealed a consistent set of shell characteristics in the Fernando de Noronha species, setting it apart from specimens gathered in other regions. This evidence supports its classification as an isolated, endemic species. As much that it was described as new other two times ( Caetano & Absalão, 2005: P. xavante ; Simone, 2009: P. noronhensis ). As discussed earlier, the species with a wide distribution and a more inflated shell requires renaming through the revalidation of the oldest synonym. A study on the separation among four species of Polyschides was conduct- ed by Souza & Caetano (2020) based on morphometric analysis of the shell. They obtained an interesting result, summarized in their graphic of the fig. 3A, showing an overlap between their examined samples of P. xavante and P. noronhensis , and a separation of the sample of P. quadridentatum (what they called P. tetrachristus ). That result is congruent with the taxonomic resolution proposed here.

Figures

Figure 65.Polyschidestetraschistusshells of typespecimens:(A) holotypeof SiphodentaliumtetraschistumBMNH 1887.2.9.66(L 6.6mm),left view;(B)same,dorsal view;(C) same,detail of posterior end;(D-E) holotype of Polyschides xavanteIBUFRJ 14190 (L 5.4 mm), leftand dorsal views;(F)holotype of Polyschidesnoronhensis MZSP 88441, leftview (L 8.6mm);(G) paratype MZSP 46736,detail of posterior region,left view,scale:= 0.25 mm;(H) replication of Dall (1889:pl. 27, fig.5) illustration of Cadulusquadridentatus(L 13.2mm);(I) Polyschidesquadridentatum holotypeMCZ 7739 (L 9.5mm),rightview;(J)same,anteriorview;(K) same,posterior view; (L) replication of Bush (1885: pl. 45, fig. 20) illustration of Cadulus incisus (L 8 mm); (M) ordinary specimen of P.quadridentatum, MZSP 119346 (L 6.1 mm) (from Itaparica,Bahia,Brazil) (courtesyVitor A.Fogarolli),left view;(N) same,dorsal view;(O) same,detail of posterior end,right view,scale:= 1 mm.