On the identity of Porcellana paivacarvalhoi Rodrigues da Costa, 1968 (Crustacea: Anomura: Porcellanidae)

. Porcellana paivacarvalhoi Rodrigues da Costa, 1968, described from southeastern Brazil (São Sebastião, São Paulo), is morphologically similar to the eastern Atlantic P. platycheles (Pennant, 1777), and also to the west African P. africana Chace, 1956. The synonymy between P. paivacarvalhoi and P. platycheles was proposed by previous authors without examination of any specimens of P. platycheles, nor did they considered the morphological similarities between P. paivacarvalhoi and P. africana. This synonymy has been implicitly accepted without further analysis. The recent discovery of one male and two females syntypes of P. paivacarvalhoi has prompted new investigations into the status of P. paivacarvalhoi as a junior synonym either of P. platycheles or P. africana. Porcellana paivacarvalhoi is redescribed and illustrated based upon its lectotype herein designated. It is confirmed to be a junior synonym of P. platycheles; all evidence suggests that P. africana is a distinct, separate species. All previous records of P. platycheles from the Brazilian coast are reviewed. Its presence in southeastern Brazil in the late 1960’s most probably represents an historical case of human-mediated introduction by shipping activities. Porcellana platycheles did not manage to establish itself in São Sebastião, nor has it been recorded subsequently elsewhere in Brazil.

The specimens of P. paivacarvalhoi originally described by Rodrigues da Costa were actually in his collections before they (or part thereof ) went to the Museu de Zoologia, Universidade de São Paulo, Brazil (MZUSP) in 1987. The specimen MZUSP 8951 studied by Veloso & Melo (1993) no longer exist in MZUSP. However, the recent finding of 3 syntypes of P. paivacarvalhoi prompted us to revisit the status of P. paivacarvalhoi as a synonym of P. platycheles.
It has been confirmed recently that specific status should be given to Porcellana platycheles africana Chace, 1956, a shallow water species originally known from western Sahara to Senegal, and recently introduced to South Africa (Griffiths et al., 2018;see also d'Udekem d'Acoz, 1999). Porcellana platycheles and P. africana differ morphologically from each other only in minor details. Their strong morphological similarity in addition to the human-mediated introduction of P. africana into the South African coast, has prompted us to clarify the identity of P. paivacarvalhoi based upon its type material.
Since its original description, P. paivacarvalhoi remains briefly and poorly described and no prior illustrations of this species have been published. Therefore, this opportunity is taken to redescribe and illustrate the lectotype as herein designated. All previous records of P. platycheles from the Brazilian coast are reviewed.

MATERIAL AND METHODS
The studied specimens are deposited in the collections of the Museu de Zoologia, Universidade Redescription of the lectotype: Carapace subcircular, longer than broad in males and females, slightly rugose dorsally, pubescent. Front-orbital region depressed, smooth. Frontal width approximately ⅓ maximum carapace width. Frontal margin serrate, fringed with short setae; trilobate in dorsal and frontal views; median lobe rounded, overreaching lateral lobes; lateral lobes rounded. Outer orbital angle well defined, rounded, with spinulate margin. Carapace anterolateral margin spinulate. Carapace lateral margin well-defined by row of conspicuous spines. Epibranchial region slightly swollen. Epibranchial angle well-defined by distinct notch; cervical groove well-defined. Carapace posterolateral surface plicate; posterior margin concave. Branchiostegite entire (without membranous areas), with longitudinal, subparallel, pilose wrinkles; superoanterior region spinulate. Branchiostegal margin fringed with long, plumose setae.
Ocular peduncle short, smooth. Orbit with smooth margin, fringed with short setae. Cornea large, dilated.
P1 slightly unequal, robust, flattened, covered with dense, short setae dorsally; propodus and dactylus with sparse granules, more evident next to pollex; smooth ventrally, devoid of setae. Merus approximately ¼ length of carpus; mesial lobe well-developed, rounded, spinulate; distal spine ventrally. Carpus approximately half length of propodus, with subtriangular, spinulate lobe on proximal third mesially; distal spine laterally, lateral margin with row of spines. Propodus broad, lateral margin with row of spines; fringed with long, dense, plumose setae laterally. Fixed finger approximately ⅓ total length of propodus; not overreaching dactylus. Dactylus longer than fixed finger. Fingers tip curved; cutting edges of fingers with conspicuous granules, with traces of short setae.

Remarks:
Porcellana paivacarvalhoi was established based on 4 males and 3 females from southeastern Brazil (São Francisco beach, São Sebastião, São Paulo), one male and one female of which remain in the collections of the MZUSP and one additional female was retrieved from MOUFPE. The syntypes were originally in Rodrigues' da Costa collection and, after his death, the remains of his original collections were donated to MZUSP. The female housed at the MOUFPE was a donation from MZUSP. The male syntype is better preserved than either of the females and therefore is herein chosen as the lectotype (MZUSP 40050, Figs. 1A-J; 2A-D). The females (MZUSP 10621; MOUFPE 7734) are the paralectotypes. The designation of the lectotype and its redescription and illustration are made in an effort to clarify the identity of the species and promote nomenclatural stability.
Rodrigues da Costa (1968) stated that P. paivacarvalhoi was similar to the eastern Atlantic P. platycheles and, more particularly, to the west African P. platycheles africana Chace, 1956. Veloso & Melo (1993 placed P. paivacarvalhoi in synonymy with P. platycheles based on the examination of one "male paratype" [sic] (MZUSP 8951). That specimen no longer exists in the MZUSP collections, however there is no evidence that it was indeed a syntype, and it is unclear from their publication whether Veloso & Melo ever compared the purported syntype of P. paivacarvalhoi with specimens of P. platycheles. Furthermore, they never addressed the morphological similarities between P. paivacarvalhoi and P. africana, whose specific status has recently been confirmed by Griffiths et al. (2018) (see also d'Udekem d' Acoz, 1999). Despite this, the synonymy between P. paivacarvalhoi and P. platycheles has been implicitly accepted without further analysis (Melo, 1999;Rodríguez et al., 2005;Osawa & McLaughlin, 2010;Griffiths et al., 2018).
Porcellana paivacarvalhoi resembles P. africana in having the lateral margin of the P1 carpus armed with one conspicuous terminal spine, but can be distinguished from it in that the lateral margin of the P1 carpus is armed with 1, 2 or more spines of different sizes (Figs. 1G;2C,D). Conversely, the lateral margin of the P1 carpus has no spines other than the distal one in P. africana (Chace, 1956;Griffiths et al., 2018). Porcellana africana further differs in being overall less spinose and more tuberculate and rugose beneath the pubescence covering the carapace, whereas the carapace is nearly smooth dorsally in P. paivacarvalhoi (Figs. 1A; 2A). Porcellana paivacarvalhoi is not, therefore, a synonym of P. africana.
In P. paivacarvalhoi, as in P. platycheles, the carapace is nearly smooth dorsally, whilst its anterolateral and lateral margins have conspicuous spinules (Figs. 1A, C; 2A; 3A); the carapace and P1 dorsal surfaces are provided with either short or long setae; the antennular basal segment with 1 or 2 anterolateral spines (Figs. 1D; 3D); the lateral margin of the P1 carpus is armed with 1, 2 or more spines of different sizes (Figs. 1G; 3G); the P1 carpus mesial lobe is either well developed (Figs. 1G; 3G) or inconspicuous; and the P2-P4 dactyli have a longitudinal row of 5 or 4 spines ventrally (Figs. 1H; 3H, respectively). In addition to the P1 lateral spines, P. paivacarvalhoi further resembles P. platycheles in having conspicuous spinules on both the anterolateral and lateral margins of the carapace, and a nearly smooth carapace and P1. In these and other respects P. paivacarvalhoi lacks sufficient morphological differences to be recognized as a separate species from P. platycheles and, therefore, is confirmed herein to be its junior synonym.
The native range of Porcellana platycheles is in the eastern Atlantic (from Ireland southward to the Canary Islands) and in the Mediterranean Sea, from the intertidal zone down to 5 m (d'Udekem d'Acoz 1999). Its presence in São Sebastião in southeastern Brazil in the late 1960s most probably represents an historical case of human-mediated introduction by shipping activities. Indeed, São Sebastião, which started operation in 1963, is a busy city port catering to ocean-going vessels. The repeated presence of eastern Atlantic/Mediterranean species in southeastern Brazil (Tavares, 2011;Tavares & Mendonça, 2004;Tavares & Rössener, 2019; this report), indicates human-mediated connectivity between eastern Atlantic source areas and Brazilian points of entry and is a reflection of the level of inoculation pressure in the 1960s.
Porcellana platycheles did not manage to establish itself in São Sebastião, nor has it been recorded subsequently from elsewhere in Brazil. Macedo et al. (2012) reported on 1 male and 5 females (MHNCI 3840,3684,3130) purportedly belonging to P. platycheles associated with mussel farming in Santa Catarina, south Brazil. However, upon examination all these specimens proved to be Pisidia brasiliensis Haig in Rodrigues da Costa, 1968.