Research Article |
Corresponding author: Alexandra Hiller ( alexandrahiller40@gmail.com ) Academic editor: Célio Magalhães
© 2024 Alexandra Hiller, Bernd Werding.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Hiller A, Werding B (2024) Description of a new species of the Petrolisthes galathinus complex from the Caribbean Sea, and resurrection of Petrolisthes occidentalis from the East Pacific (Crustacea, Anomura, Porcellanidae). ZooKeys 1191: 391-407. https://doi.org/10.3897/zookeys.1191.111570
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The Petrolisthes galathinus complex currently consists of six American species distributed in the West Atlantic, including the amphi-American P. galathinus. All species in the complex are similar in their adult morphology but differ in colour, size, larval morphology, and shape of the adult sternal plate. The West Atlantic species have different geographic ranges, which overlap in the southern Caribbean. Previously published molecular data support the monophyly of the complex, and the reciprocal monophyly of each described species and further clades corresponding to different colour morphs. Here, the morph P. caribensis “Blue” is described as Petrolisthes coeruleus sp. nov., and Petrolisthes occidentalis is formally resurrected for the Pacific individuals of P. galathinus. By adding these two species to the P. galathinus complex, this now consists of eight species. Colour illustrations of all species and colour morphs are provided and their geographic distributions and ecological ranges are discussed and updated.
Caribbean, colour morphs, ecological range, geographical range, Petrolisthes coeruleus sp. nov., Petrolisthes occidentalis
Petrolisthes galathinus (Bosc, 1802) is an American species, described as Porcellana galathina because of the transverse piliferous ridges covering carapace and extremities resembling those of the galatheid genus Galathea (Fig.
Regarding the possible type locality of P. galathinus,
In the decades following Bosc´s description, West Atlantic species of Petrolisthes with piliferous transverse ridges on carapace and extremities were reported as P. galathinus from localities throughout the Caribbean and southwards to Brazil. The eastern Pacific individuals, morphologically matching P. galathinus, were described as Petrolisthes occidentalis Stimpson, 1859, based on specimens collected in Panama. However,
In her study on the Porcellanidae of the western North Atlantic,
Morphotypes and distinguishing characters of the Petrolisthes galathinus complex.
Species | Number of epibranchial spines | Number of spines on inner border of dactylus of all walking legs | Maximum size of male adults (carapace width in mm) |
P. bolivarensis Werding & Kraus | 1 | 3 | > 15.0 |
P. caribensis Werding | 1 | 4 | 9.4 |
P. coeruleus sp. nov. | 1 | 4 | 12.4 |
P. columbiensis Werding | 2 | 4 | 7.2 |
P. galathinus (Bosc) “Stripes–Spots” | 1 | 3 | > 14.0 |
P. galathinus (Bosc) “White Teeth” | 1 | 3 | > 15.0 |
P. occidentalis Stimpson | 1 | 3 | > 17.0 |
P. rosariensis Werding | 2 | 4 | 6.0 |
P. sanmartini Werding & Hiller | 1 | 5 | 6.5 |
Dorsal view of a Petrolisthes rosariensis, male, Islas del Rosario, Colombian Caribbean b P. columbiensis, female, Islas del Rosario, Colombian Caribbean c P. caribensis, male, Islas del Rosario, Colombian Caribbean d P. caribensis, Roatán, Honduras, photo courtesy of M. Charteris. Scale bars: 0.6 cm (a); 0.8 cm (b); 0.3 cm (c).
Dorsal view of colour morphs within Petrolisthes galathinus, as designated by
Here, we describe P. coeruleus sp. nov. (Figs
Material of Petrolisthes coeruleus sp. nov. collected in Belize and the Panamanian and Colombian Caribbean, and of P. occidentalis collected in the Panamanian East Pacific, was used for morphological examination. Type material of the new species was deposited in the
Senckenberg Naturmuseum Frankfurt (
Family Porcellanidae Haworth, 1825: 184.
Genus Petrolisthes Stimpson, 1858: 227.
Petrolisthes galathinus Werding, 1982: 443 (part, Islas del Rosario).
Petrolisthes caribensis
“Blue”:
Holotype : Male, MUPADI–Crus–14, West Atlantic, Panamá, Colón, Punta Galeta, 9°24.161'N, 79°51.634'W; in Porites porites (Pallas, 1766), 0.5 m, leg. A Hiller, 12 Apr. 2021; 9.53 × 8.98 mm; female (ov) 8.83 × 7.78 mm; female 7.65 × 7.22 mm. Paratypes: MUPADI–Crus–02–16, same data as holotype; female (ov) 8.83 × 7.78 mm; female 7.65 × 7.22 mm. SMF57499, West Atlantic, Colombia, Bolívar, Islas del Rosario, Isla San Martín de Pajarales, 10°10.637'N, 75°46.234'W; in coral gravel, 1–2 m, leg. B. Werding, Sep. 2001; female (ov) 7.0 × 6.8 mm; male 7.3 × 7.0 mm; male 7.7 × 7.6 mm; male 5.4 × 5.2 mm; female (ov) 7.7 × 7.4 mm; female (ov) 7.6 × 7.6 mm; male 6.1 × 5.8 mm; female (ov) 7.5 × 7.7 mm; female (ov) 6.4 × 6.5 mm; male 5.4 × 5.3 mm; female 6.1 × 6.2 mm.
(personal collections by the authors). West Atlantic, Belize, Carrie Bow Cay, 16°48.188'N, 88°5.067'W; under blocks of dead elkhorn coral, 1–2 m, leg. A. Hiller, Jun. 2016; male 5.1 × 4.9 mm; female 5.3 × 5.0 mm.
Carapace slightly longer than broad, evenly rounded along branchial margins, broadest on midbranchial level. Surface with transverse, piliferous plications, one epibranchial spine present. Front sinuously triangular with a longitudinal depression, its borders fringed by a row of spinules, giving a serrated aspect; orbitae moderately deep, supraocular spine strong, postorbital angle produced into a spine-tipped tooth. Eyes moderately large, dorsal extension onto cornea narrow. Basal segment of antennulae with some transverse rugae, anterior margin with teeth. First movable segment of antennae with a serrated, spine-tipped lamellar lobe; second and third segments slightly rugose, flagellum naked.
Chelipeds sub-equal, surface with piliferous striations, merus rugose with serrated, spine-tipped lobe on anterior margin; carpus about two times as long as broad, armed on anterior margin with four, seldom five broad, serrated teeth; posterior margin slightly convex, armed with a row of strong, forwardly directed curved spines. Palm of manus broad with an inconspicuous longitudinal ridge ending at angle between fixed finger and pollex. Lateral surface of dactylus with interrupted transverse, piliferous striations; lateral surface of pollex with rough, conical protuberances extending to fixed finger; outer margin of palm convex, with row of strong, forwardly directed spines, frequently fringed with feathered setae. Gape of fingers with extended ventral pubescence covering proximal portions of pollex and dactylus. Walking legs rugose; anterior margin of merus with fringe of plumose setae, all segments covered with irregularly, wide-set, simple setae; anterior margin of merus with row of spines; large posterodistal spine on merus of walking legs 1 and 2, frequently a smaller one on leg 3; carpus of all walking legs with anterodistal spine; propodus with terminal triplet of movable spines on ventral border, with one or two additional ones; dactylus large, with four movable spinules on inner margin.
Telson seven-plated with a few short, transverse, piliferous ridges.
The overall colouration of most specimens consists of a brownish beige background, partly overlaid with iridescent blue tones towards the posterior part of the carapace and on the chelipeds; the transverse ridges of carapace and extremities are marked by blue stripes delineated by narrow dark purple lines. The distal articulations of the walking legs are spotted with blue and purple (Fig.
The new species was first perceived as a different colour morph of P. caribensis, as they are not distinguishable through the two main diagnostic traits (Table
While Petrolisthes caribensis is a typical inhabitant of shallow-water coralline environments, mostly in the dead bases of the finger coral Porites porites (Pallas), Petrolisthes coeruleus sp. nov. has a wider habitat spectrum and depth range, as it occurs under boulders in protected sites of the surf zone. The authors found the species on roots of the red mangrove Rhizophora mangle L. in a coastal lagoon in the Colombian Gulf of Morrosquillo (9°41.684'N, 75°41.135'W), and also in the furrows of the giant barrel sponge Xestospongia muta (Schmidt, 1870) at 8 m depth in the same locality (Table
Geographic and ecological range of the species and colour morphs comprising the Petrolisthes galathinus complex and allied species. WA = West Atlantic; EP = East Pacific;
Species | Geographic range | Ecology |
---|---|---|
Parapetrolisthes tortugensis (Glassell, 1945) | WA: Florida, Bahamas, Gulf of Mexico, Belize, Costa Rica, Panama, Colombia, Venezuela, Antilles ( |
Coral rubble, from sponges of the genus Ircinia Nardo, 1833; pers. comm. F. Sanford), 0.5–54 m ( |
Petrolisthes bolivarensis | WA: Florida, Panama, Colombia, Venezuela ( |
Dead part of Porites porites (Pallas, 1766), under boulders in protected sites of the surf zone, under dead blocks of Acropora palmata (Lamarck, 1816), 0–1.5 m ( |
Petrolisthes caribensis | WA: Florida, Bahamas, Gulf of Mexico, Belize, Panama, Colombia, Venezuela, Antilles, ( |
Dead part of Porites porites, under dead blocks of Acropora palmata, 0.5–22 m, on coral heads and rubble in shallow waters at 4 m, on outer reef slope ≤11 m ( |
Petrolisthes coeruleus sp. nov. | WA: Bahamas, Gulf of Mexico, Belize, Panama, Colombia ( |
Dead part of Porites porites, under boulders in protected sites of the surf zone, under dead blocks of Acropora palmata, on roots of Rhizophora mangle Linnaeus, 1753, in the furrows of Xestospongia muta (Schmidt, 1870), 8 m ( |
Petrolisthes columbiensis | WA: Colombia, Cuba ( |
Dead part of Porites porites, 1–6 m ( |
Petrolisthes galathinus “Stripes–Spots” | WA: Panama, Colombia, Guyana, Brazil ( |
Dead part of Porites porites, in reef of Agaricia Lamarck, 1801, under boulders in protected sites of the surf zone, 0.5–3 m ( |
Petrolisthes galathinus “White Teeth” | WA: Florida, Gulf of Mexico, Belize, Panama, Colombia, Venezuela, Antilles, possibly along the east coast of Florida ( |
Dead part of Porites porites, under dead, large blocks of Acropora palmata, under boulders in protected sites of the surf zone, on coral heads, 0.5–6 m ( |
Petrolisthes occidentalis | EP: Mexico (Cuastecomate Bay, Jalisco), El Salvador, Costa Rica, Panama, Colombia, Ecuador ( |
Under boulders at 0–2 m; dredged from sand and sand-shell bottoms at 7.2 and 18 m; among rocks with oysters ( |
Petrolisthes rosariensis | WA: Bahamas, Gulf of Mexico, Belize, Panama, Colombia, Venezuela, Antilles, Brazil ( |
Dead part of Porites porites, under dead, large blocks of Acropora palmata, under boulders in protected sites of the surf zone, on coral heads, in Agaricia coral reef framework, under boulders ( |
Petrolisthes sanmartini | WA: Bahamas, French Antilles, Colombia ( |
Dead part of Porites porites, in coral rubble; subtidal to 18 m ( |
Petrolisthes coeruleus sp. nov. is, so far, known from the Colombian and Panamanian Caribbean, Belize, and the east coast of Mexico. R. Lasley (
The name coeruleus alludes to the blueish tone of carapace and extremities, which comprises a reliable diagnostic character to distinguish this species from P. caribensis.
Petrolisthes occidentalis
Stimpson, 1858: 227 (nomen nudum; listed);
Petrolisthes galathinus
Ortmann, 1897: 284;
Syntypes
:
MUPADI–Crus–02–17, East Pacific, Panamá, Panama City, Punta Culebra, under large boulders, low intertidal, leg. A. Hiller, 21 Feb. 2015; male, 12.8 × 13.5 mm; male, 12.9 × 13.4 mm.
Petrolisthes occidentalis morphologically resembles the other members of the P. galathinus complex. An extensive description was given by
The transverse ridges and tubercles, which are typical of the members of the Petrolisthes galathinus species complex, are bordered with purplish red bands, the intervening grooves are yellowish, the yellow colour prevailing on the carpus teeth. The merus of the walking legs is irregularly spotted with purplish dots, the carpus and propodus show three broad, purplish bands alternating with paler yellowish ones (Fig.
Petrolisthes occidentalis was listed by
For more than two centuries Petrolisthes galathinus has been viewed as a widely dispersed species in the West Atlantic and East Pacific, with a broad ecological range, inhabiting a variety of substrates like rocks, corals, and sponges, and from the upper subtidal down to 50 m depth. This species turned out to be a complex of morphologically similar species; so far, the P. galathinus complex encompasses eight species, including P. coeruleus sp. nov. and the resurrected P. occidentalis. Each species is supported by distinctive mitochondrial DNA sequences, colouration, adult size, larval morphology, and shape of the sternal plate. All species, except P. rosariensis, share a most recent common ancestor (MRCA), which started diverging into different Atlantic and Pacific lineages before the Central American Isthmus finished rising and interrupted gene flow between populations from each ocean (
Petrolisthes galathinus still needs more revision, as it is unclear which of the molecular clades, designated in the phylogeny by
The P. galathinus complex poses an interesting case to study speciation within allopatric and sympatric scenarios, as it comprises closely related species on either side of the Isthmus of Panama. Such a unique assemblage allows assessing the relationship between genetic divergence and reproductive isolation, given the background of a relatively recent and well dated geological barrier that resulted in sister lineages on each side of the Americas (
The evolutionary, ecological, and geographic processes that gave rise to the formation of different West Atlantic species with similar geographic ranges and ecologies remains to be explained in the light of a multigene phylogeographic approach of the species complex. The overlapping geographic and ecological ranges in the southern Caribbean (Table
We thank T. Deuss (Bocas Mariculture, Panama) for supporting our collections in Bocas del Toro and for photographs of the new species. P. Quiceno (Universidad de Antioquia, Colombia), A. Baldinger (
The authors have declared that no competing interests exist.
No ethical statement was reported.
No funding was reported.
Both authors have contributed equally.
Alexandra Hiller https://orcid.org/0000-0001-9812-2126
Bernd Werding https://orcid.org/0000-0002-1311-6139
All of the data that support the findings of this study are available in the main text.