Pilumnus vinaceus A. Milne-Edwards, 1880

Magalhães, Tatiana, Pantaleão, João A. F. & Mantelatto, Fernando L., 2021, Resurrection of Pilumnus vinaceus A. Milne-Edwards, 1880 (Brachyura Pilumnidae) using integrative evidence from molecular and morphology, Zootaxa 5047 (5), pp. 547-556 : 550-553

Pilumnus vinaceus A. Milne-Edwards, 1880 [in A. Milne-Edwards, 1873-1880]

( Fig. 1 A–D )

Pilumnus vinaceus – A. Milne-Edwards, 1880: 283, pl. L, fig. 2 (type locality: Florida reefs, USA) .

Pilumnus dasypodus – Rathbun 1901: 40 (in part); Williams 1965: 178 (in part); 1984: 425 (in part); Coelho & Ramos 1972: 193 (in part); Powers 1977: 105 (in part); Lemaitre 1981: 256 (in part); Abele & Kim 1986: 51, 193 (in part); 1989: 37 (in part); Melo et al. 1989: 17 (in part); Melo 1996: 382 (in part); Melo 1998: 487 (in part); Bosa & Masunari 2000 (population ecology); Braga et al. 2005: 31; Almeida & Coelho 2008: 201 (in part); Coelho et al. 2008: 27 (in part); Melo 2008: 9 (in part); Bertini et al. 2004: 2191, 2202; Branco & Fracasso 2004: 299; Marochi & Masunari 2011: 23, 28; Alves et al. 2012b: 502, 507; Boos et al. 2012: 1031; Branco et al. 2015: 6.

Material examined. Syntypes, 2 males, cw 11.8 mm and 5.4 mm, west of Tortugas, Florida, United States, 1877-78, coll. Coast Survey Steamer Blake, under the supervision of Alexander Agassiz, MCZ 3049 . Additional material. United States: 1 female cw 10.0 mm and 1 male cw 12.6 mm, South Padre Island , Texas, 1 December 1998, coll. D.L. Felder, ULLZ 4432 . Belize: 1 male, cw 16.1 mm, Carrie Bow Cay Field Station , Stann Creek, 1 October 2002, coll. Cole et al., ULLZ 10826 ; 1 female, cw 15.3 mm, Carrie Bow Cay Field Station , Stann Creek, 1 October 2002, coll. Cole et al., ULLZ 10828 ; 1 female, cw 7.9 mm and 1 male, cw 5.2 mm, Twin Cays , 24 April 2015, coll. Felder et al., ULLZ 16547 . Martinique: 1 male, cw 9.9 mm, date not informed, coll. Mr. Fisher, MNHN-IU-4322 (= MNHN-B4322 ) . Panama: 1 ov. female, cw 8.9 mm, Bocas del Toro, 10 August 2011, coll. Taxonomy class, ULLZ 17033 . Brazil: 1 ov. female, cw 11.8 mm, Praia dos Coqueiros , Piauí, date and coll. not informed, MZUSP 33213 ; 3 ov. females and 3 males, cw 6.9 mm, 6.5 mm, 5.7 mm, 8.2 mm, 7.8 mm and 6.3 mm, Praia da Pedra Rachada, Paracuru , Ceará, 14 November 2015, coll. F.L. Mantelatto et al., CCDB 6191 ; 1 female, 2 ov. females and 2 males, cw 7.1 mm, 7.1 mm, 7.5 mm, 7.9 mm and 5.5 mm, respectively, Praia do Pacheco, Caucaia , Ceará, 12 February 2013, coll. F.L. Mantelatto et al., CCDB 5383 ; 1 male, cw 7.6 mm, Praia do Paiva, Recife , Pernambuco, 17 April 2014, coll. F.L. Mantelatto and F.B. Mantelatto, CCDB 4995 ; 1 male, 14.9 mm, Espírito Santo, 9 April 1993, coll. not informed, MZUSP 32326 ; 1 female, cw 17.0 mm, Macaé , Rio de Janeiro, 11 April 2002, coll. N.O.A. Garoupe, MNRJ 17249 ; 1 female, cw 6.0 mm, Praia Ferradura, Búzios , Rio de Janeiro, 15 November 2011, coll. E. Ocampo, CCDB 3716 ; 1 female, cw 9.9 mm, Píer do Itaguá, Ubatuba , São Paulo, 15 September 2008, coll. F.L. Mantelatto, CCDB 4598 ; 1 male, cw 7.1 mm, Ubatuba , São Paulo, 31 April 2014, coll. F.L. Mantelatto et al., CCDB 5850 ; 2 females and 2 males, cw 8.6 mm, 6.4 mm, 7.5 mm and 8.2 mm, respectively, Praia do Itaguá, Ubatuba , São Paulo, 16 October 2012, coll. F.L. Mantelatto et al., CCDB 5660 ; 1 female e 1 male, cw 4.0 mm and 8.5 mm, respectively, Praia do Itaguá, Ubatuba , São Paulo, 02 December 2014, coll. F.L. Mantelatto et al., CCDB 5670 ; 1 male, cw 7.9 mm, Ubatuba , São Paulo, 16 October 2012, coll. F.L. Mantelatto et al., CCDB 5677 ; 1 female, cw 11.1 mm, Ubatuba , São Paulo, 16 October 2012, coll. F.L. Mantelatto et al., CCDB 6193 ; 2 females and 2 males, cw 6.2 mm, 3.7 mm, 9.4 mm and 3.9 mm, respectively, Praia do Itaguá, Ubatuba , São Paulo, 03 April 2011, coll. I. Leone and T . Magalhães , CCDB 6194 ; 1 ov. female, cw 9.2 mm, Praia do Itaguá, Ubatuba , São Paulo, 17 October 2012, coll. F.L. Mantelatto et al., CCDB 5382 ; 1 male, cw 5.7 mm, Ilha de Búzios, Ilhabela , São Paulo, 10 April 2013, coll. F.J. Zara et al., CCDB 5919 ; 1 ov. female, cw 13.2 mm, Ilha de Búzios, Ilhabela , São Paulo, 10 April 2013, coll. F.J. Zara et al., CCDB 6702 ; 1 male, cw 17.7 mm, Florianópolis, Santa Catarina , 20 March 1998, coll. A. R . Magalhães , MZUSP 12570 .

Diagnosis. Carapace outline sub-hexagonal, dorsal surface of carapace with sparse clavate setae and stiff simple setae not concealing surface anteriorly, presence of small granules, teeth and/or spines on anterolateral region and a row of granules at base of the last anterolateral spine towards the gastric region, regions very poorly marked; frontal lobes convex to either side of strong median indentation; supraorbital and infraorbital margins with spines and/or teeth; anterolateral margin with 4 spines, including outer orbital angle. Major chela with upper and proximal surfaces covered by longitudinal rows and groups of heavy spines or spiniform tubercles, between which rows are coarse interspersed among smaller granules, clavate setae and stiff setae; more than two thirds of outer surface smooth.

Description. Carapace sub-hexagonal ( Figs. 1A, B ) with anterior and posterior regions both sloped downward, dorsum longitudinally arched; dorsal surface with sparse simple setae not concealing surface anteriorly, with few tufts of longer stiff setae, some clavate, on the gastric and branchial regions; presence of small granules, teeth and/or spines on anterolateral region and line of granules at base of last anterolateral spine towards gastric region; dorsal surface overall smooth, bearing few small granules, regions poorly marked; fronto-orbital width more than half the greatest width of carapace, excluding spines; front with 2 divided into 2 prominent convex lobes, separated by strong median indentation, lobes smooth with longitudinal row of simple longer setae, distal margins with granules and/or teeth; antennal sulcus between lateral and to frontal lobe rounded, unarmed, sulcus ending terminating laterally in antennal tooth or spine; subhepatic region with small granules; pterygostomial region granulate; anterolateral margin with 4 spines, anterior most narrow, formed of outer orbital angle, surmounted by subacute spine, second through fourth distinctly conical; supraorbital and suborbital infraorbital margins ( Figs. 1A, B , respectively) with strong teeth or spines, lined by small rounded to subacute granules. Third maxilliped ischium twice length of merus; ischium and merus both with acute distomesial corners, that of merus produced distally. Chelipeds unequal ( Figs. 1A, B ). Minor cheliped carpus and chela covered with spines, spiniform tubercles, granules on upper, lower, and outer surfaces, entirely covering outer surfaces of palms, strong elongate setae, some clavate, especially on outer and upper surface of chela, including dactylus and fixed finger. Major cheliped ( Fig. 1A ) carpus, upper and proximal chela surfaces covered by with longitudinal rows and fields of heavy spines or spiniform tubercles, between which rows are coarse interspersed among smaller granules and strong elongate setae, some clavate; half or more of smooth outer surface.

Distribution. western Atlantic – Gulf of Mexico ( USA: Texas, Florida), Central America ( Belize; Panama) and South America ( Brazil: Piauí, Ceará, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Santa Catarina).

Live coloration. Background dorsal surface of the carapace color light orangish or light brownish in the posterior region becoming darker in the anterior region or sometimes with dark and light orange and white spots in the anterior region becoming whitish on the margins; chelipeds dark orangish in the upper and proximal region, light orangish to whitish on the outer surface; ambulatory legs surface color whitish to light orangish; most of the time the spines, fingers of the chelipeds are brownish and light orangish to whitish on the tips ( Fig. 1A, B ).

Remarks. Alphonse Milne-Edwards (1880: 283) described the species from an unspecified number of specimens from a location between Florida and Cuba, noting he also had one specimen from Martinique, but also saying that the species is common in Florida. Rathbun (1897: 16) synonymised P. vinaceus under P. dasypodus without any comment, only indicating she had “authentic specimens” of the former. Rathbun (1930: 493) reaffirmed the synonymy without comment and noted she had examined a type specimen from Florida reefs. However, after analyzing the original descriptions of Kingsley (1879: 155) for P. dasypodus , a specimen on the Yale Peabody Museum of Natural History (catalog number: YPM IZ 022640, indicated as type), the original description of A. Milne-Edwards (1880: 283) for P. vinaceus , the syntype of this species at the MCZ in Boston (MCZ 3049) and different fixed specimens from Brazil, Central America and Gulf of Mexico, we verified that biggest adults of P. vinaceus differs from P. dasypodus due the granulations in the hepatic region and a row of granules at the base of the last anterolateral spine towards the gastric region ( Fig. 1A ). Pilumnus dasypodus presents the whole carapace very smooth without the spines on the hepatic and pterygostomial regions. These morphological characteristics allows the separation of adults of both species. However, the two species are remarkably similar, being possible to distinguish them only among the biggest adults. Small adults or juvenile individuals, in turn, are practically identical. In the fixed specimens analyzed we did not find other morphological differences between male and female, or such as chela, gonopod morphology or different color pattern as observed among the mud crabs species of Panopeus by Schubart et al. (2000) or the purse crabs Persephona by Magalhães et al. (2016).

We are convinced that the illustrations from A. Milne-Edwards, 1880: 283, pl. L, figs. 2, 2a and 2b, together with the two syntypes analyzed are enough to represent the species, because it is possible to recognize the diagnostic characters (such as the granulations in the hepatic region and a row of granules at the base of the last anterolateral spine towards gastric region). These characters allow the identification of the species and prevent doubts about its taxonomy, thus, we considered it is not necessary to designate a neotype to P. vinaceus . Because P. vinaceus occur simpatrically with P. dasypodus in part of its distribution (Gulf of Mexico to Bahia, Brazil) many earlier reports of P. dasypodus could represent P. vinaceus . As animals from these reports are unavailable, or if available, it is not possible to ascertain the true identity, to avoid confusion, our synonymy included only reports of P. dasypodus that could potentially represent in full or in part P. vinaceus . Many of these studies are faunistic lists where P. dasypodus was listed as part of the inventory.

In the molecular analysis, 21 specimens belonging to 14 species of Pilumnus ( Table 1) were compared. The interspecific pairwise distances based on COI ranged from 6% ( P. pannosus vs. P. lacteus ) to 19% ( P. mantelattoi vs. P. marshi ) between well-defined morphological species. The minimum value observed between P. dasypodus and P. vinaceus was 6% indicating that these two species are genetically distinct. While the interspecific pairwise distance based on 16S ranged from 2% ( P. lacteus vs. P. pannosus ; P. lacteus vs. P. reticulatus ) to 8% ( P. gemmatus vs. P. sayi ) between well-defined morphological species. The minimum value observed between P. dasypodus and P. vinaceus was 2%. Thus, the interspecific pairwise distances supporting the validity of two different species.

Through neighbor-joining (NJ) analysis, P. vinaceus was recovered as a distinct clade from P. dasypodus for both the COI gene ( Fig. 2 ) and for 16S ( Fig. 3 ) with a high support value (99 and 96%, respectively).

In this way, based on the differences observed in the morphology of carapace from specimens of P. dasypodus and P. vinaceus , including those from the type series, high genetic distance for both COI and 16S genes, and robust topology of our tree, it can be inferred that the hairy crab Pilumnus vinaceus should be resurrected as a valid entity on the western Atlantic.

Figures

FIGURE 1. Pilumnus vinaceus. CCDB 6194 – male (CW - 9.9 mm).A. Dorsal view. B. Ventral view. CCDB 6702 – ovigerous female (CW - 13.2 mm). C. Dorsal view. D. Ventral view. Scale bars = 10 mm.

FIGURE 2. A neighbor-joining (NJ) tree of species of selected species of Pilumnus from the western Atlantic, based on 652 bp of the cytochrome oxidase subunit I gene. Probability values at the nodes represent bootstrap, values below 50 are not shown.

FIGURE 3. A neighbor-joining (NJ) tree of species of selected species of Pilumnus from the western Atlantic, based on 502 bp of the 16S ribosomal (r)RNA gene. Probability values at the nodes represent bootstrap, values below 50 are not shown.