Gecarcinus ruricola ( Linnaeus, 1758 )

Gecarcinus ruricola ( Linnaeus, 1758) View in CoL

( Figs 1-4 View FIG View FIG View FIG View FIG ; 6 View FIG ; 10A, D View FIG ; 11A View FIG ; 16-18 View FIG View FIG View FIG ; 21 View FIG ; Table 1 View TABLE )

Cancer ruricola Linnaeus, 1758: 626 . — Herbst 1783: 119, pl. 3 fig. 36, pl. 4 fig. 37; 1790: 262, pl. 20 fig. 116; 1799: 39, pl. 49 fig. 1. — Fabricius 1798: 339. — Latreille 1817: 17.

Ocypode tourlourou Latreille, 1803 : only pl. 44 fig. 2 (see below under Ocypode tourlourou Latreille, 1803 ).

Gecarcinus ruricola View in CoL – Leach 1815: 322. — H. Milne Edwards 1837 a: 26; 1837b: pl. 20, fig.1, a-c. — Desmarest 1825: 113, pl. 11 (nec 12) fig. 2. — Bosc 1830: 252. — Lamarck 1838: 459. — Desbonne in Desbonne & Schramm 1867: 42. — Verrill 1892: 353. — Stebbing 1893: 80-84. — Doflein 1899: 181. — Rathbun 1918: 352-355, fig. 160, pls 117, 118; 1920: 341 [19]; 1924: 19; 1936: 38. — Chace 1940: 53. — Chace & Holthuis 1948: 26. — Hartnoll 1968: 297; 2015: 400, 402, 404, tables 1, 3. — Chace & Hobbs 1969: 194, 200, figs 66, 67h-j. — Bright & Hogue 1972: 20. — Powers 1977: 140. — Keith 1985: 276, fig. 12B. — Mulder & Stam 1987: 1-40. — Britton et al. 1982: 207. — Abele & Kim 1986: 62, 661, 663, fig. a, c. — Atkin 2004. — Venable 2004: unnumbered page and photo. — Baine et al. 2005: 1-59, figs 1-10. — Hartnoll et al. 2006a: 316-325 View Cited Treatment , figs 1-4, tables 1-7. — Hartnoll & Clark 2006: 149-164 View Cited Treatment . — Hartnoll et al. 2007: 425-436; 2014: 532, 534, 538, fig. 1A; 2017: 947, 949, table 4. — Lalana et al. 2007: 82. — Felder et al. 2009: 1088. — Barro et al. 2013: 45. — Vaslet et al. 2013: 245, annex 3. — Yokoyama 2013 114. — Diez 2014: 83. — Diez & Jover 2015: 16, fig. 7m-p. — Vides et al. 2016: fig. 25. — Diez & Soto-Borrero 2016: 79. — Diez & Espinosa 2018: 151. — Questel 2018: 15; 2019: 12 (and photo), 25 (and unnumbered photos), 33. — Guinot et al. 2018: 568, 569, 572, 586, 587, fig. 7A-D. — Poupin 2018: 223, fig. 254. — Parasram et al. 2021: 457 View Cited Treatment , fig. 9. — Toledano-Carrasco et al. 2021: 218, 221, 224, 226, 230, figs 3F, G, 4, 5, tables 1, 3. — Vendeville et al. 2022: 193. — Parasram 2023:127, fig. 3.9. — Marin & Tiunov 2023: 96, 117. — Pinheiro et al. 2024: 2, 7.

Geocarcinus ruricola – Young 1900: 238, 239.

Gecarcinus ( Gecarcinus) ruricola View in CoL – Türkay 1970: 336, fig. 1a-f. — Prahl & Manjarrés 1983: 32, fig. 2A; 1984a: 151, 155, 166, figs 1, 2, 3.1; 1984b: 6, 8. — Abele & Kim 1986: 62. — Scelzo & Varela 1988: 36, 49, fig. 4. — Acevedo 1989: 3-14. — Martinez & Bliss 1989: 3. — Ng et al. 2008: 215. — Felder et al. 2009: 1088.

Nec Ocypode ruricola – Latreille 1803: 35 (= Cardisoma guanhumi Latreille View in CoL in Le Peletier, Serville & Guérin, 1828).

Nec Ocypode ruricola – Fréminville 1835: 217 (= Cardisoma guanhumi Latreille View in CoL in Le Peletier, Serville & Guérin, 1828 fide Türkay 1970).

Nec Grapsus ( Gecarcinus) ruricola – De Haan 1850: 30, pl. c, figs below (= Gecarcoidea lalandii H. Milne Edwards, 1837 View in CoL ).

Nec Gecarcinus ruricola View in CoL – Cano 1889: 101, 227 (= Gecarcinus nobilii Perger & Wall, 2014 View in CoL ).

Nec Gecarcinus ruricola View in CoL – Nobili 1901: 46 (= Gecarcinus nobilii Perger & Wall, 2014 View in CoL ).

TYPE MATERIAL. — Neotype (by present designation). Cuba • ♂ 55.0 × 76.0 mm; in ethanol; de Boury coll. 1914; Bouvier det. as Gecarcinus ruricola ; M.Türkay vid. VI.1972; MNHN-IU-2017-8392 (= MNHN-B13155 ).

OTHER MATERIAL EXAMINED. — Cuba • 1 ♂ 66.4 × 95 mm; dry; M. Gundlach [coll]; as Gecarcinus ruricola ; MNHN-IU-2000-10953 (= MNHN-B10953 ) • 1 ♂ 66.2 × 93.3 mm; dry; M. Gundlach [coll]; as Gecarcinus ruricola ; MNHN-IU-2000-10955 (= MNHNB10955 ) • 1 ♂ 57.7 × 81.4 mm; dry; M. Gundlach [coll]; as Gecarcinus ruricola ; MNHN-IU-2000-3764 (= MNHN-B3764 ) • 1 ♂ 61.7 × 91.6 mm (as Gecarcinus ruricola ; MNHN-IU-2000-3766 (= MNHN-B3766 ) • 1 ♀ 60.5 × 83.8 mm; dry; as Gecarcinus ruricola ; MNHN-IU-2000-10754 (= MNHN-B10754 ) • 1 young ♂ 17.7 × 23.7 mm, same data as neoype; MNHN-IU-2018-5229 (= MNHN-B13155 ) • 1 ♀ 52.8 × 69.9 mm; in ethanol; M. Chaper, det. Gecarcinus ; MNHN-IU-2024-6554 • 1 ♂ 71.0 × 53.0 mm; Playa Larga , III.2004; as Gecarcinus ruricola ; ZMH-K65343 •

1 ♂ 21.2 × 27.0 mm, 3♀ 17.9 × 22.2 mm, 44.3 × 59.2 mm, one damaged; off Cape San Antonio, Ensenada de Cajon ; 21°52’00”N, 84°57’00”W; Tomas Barrera Exp., Henderson & Bartsch coll.; 22.V.1914; Rathbun det.; R. B. Manning redet.; USNM 48405 About USNM GoogleMaps • 1 ♂ 51.5 × 71.5 mm, Cabanas, 22°58’32”N, 82°55’00”W; Tomas Barrera Exp. ; st. 16 (nec depth 4-22 m); Henderson, Brooks & Bartsch coll.; 8/ 9.VI.1914; USNM 48402 About USNM (See Fig. 6H View FIG ) GoogleMaps • 3♂ 52.4 × 73.5 mm, 54.0 × 75.0 mm, 55.9 × 75.5 mm; 4 ♀ cl 52.5 mm, 42.7 × 55.9 mm, 40.9 × 54.7 mm, 53.3 × 71.4 mm; P. Bartsch coll.; 1930; R. B. Manning det.; USNM 71242 About USNM .

Cayman Islands • 1 ♂ 61.2 × 88.0 mm, Cayman Expedition 1938; English Sound, Sta. 31; Coll. & Pres. Oxford University; 11.V.1938; NHM 2024.353. Little Cayman • 3 ♂ 56.0 × 78.1 mm, 62.7 × 87.7 mm (yellow morph), 58.2 × 82.6 mm (red morph), 1♀ 68.0 × 95.2 mm (red morph); Cayman Expedition 1938, 1938; in bush and plantation; 1952.1.17.4-6; Coll. Oxford University; 11.V.1938; NHM 2024.353 [ 1 ♂ 29.3 × 37.0 mm of this sample is Hartnollius lateralis n. comb.].

Jamaica • 1♂ 56.8 × 80.2 mm; Clydesdale; coll. W. Lynn; 1.VI.1936; alt. 1067 m, Rathbun det.; USNM 72785 About USNM .

Haiti • 1 ♂ 25.4 × 32.0, 1♀ 29.0 × 35.6 mm; Coll. D. F. Weinland, MCZ n°1613, USNM 1513693 About USNM (See Fig. 6C View FIG ) .

Near Haiti, Navassa Island (Isle de la Fortune) • 6 ♂ (60.0 × 82, 9 mm Cr 63, 55.6 × 76.6 mm Cr 64, 55.9 × 75.9 mm Cr 65, 60.0 × 82.7 mm Cr 66, 55.4 × 77.0 mm Cr 67, 54.0 × 76.2 mm Cr 68; I. Sanderson; 16.XII.1937; det. A. C. Evans; NHM 1967.7.1.80- 85. (See Fig. 6A, B View FIG ).

St Kitts • 1 ♂ (many legs detached) 66.6 × 93.8 mm (red morph); 1912.6.18.1; pres. J. J. Quelch; NHM 1888.26 .

Antilles • 1 ♀ 59.8 × 82.2 mm; dry; as Gecarcinus ruricola ; MNHNIU-2000-3765 (= MNHN-B3765).

Guadeloupe • 1 ♂ 74.8 × 109.2 mm; dry; as Gecarcinus ruricola ; MNHN-IU-2000-10876 (= MNHN-B10876 ) • 1 ♂ 32.7 × 43.4 mm (red morph); Îles des Saintes ; KARUBENTHOS 3; Stn IGM4 View Materials , 15°52.44’N, 61°34.8’W; 28.IX.2024; MNHN-ARBig-LPRig coll.; Parasram det.; MNHN-IU-2024-4640; (see Fig. 6D View FIG ) GoogleMaps • 1 ♀ 41.2 × 54.2 mm, ‘red morph’; La Désirade ; Parc du Souffleur; KARUBENTHOS 3; Stn AU-EP-09, 16°18’51.0”N, 61°02’55”W, alt. 263 m; dry forest; 10.XI.2024, E. Poirier MNHN-ARBig-LPRig coll.; Parasram det.; MNHN-IU-2024-7258 (See Fig. 6E View FIG ) GoogleMaps .

Dominica • 1♂ 65.6 × 91.0 mm; near mouth of Layou River , along road at night; H. H. Hobbs Jr coll.; 14.II.1966 and det.; USNM 12693 About USNM • 1♂ 67.3 × 91.3 mm, 1 ♀ 68.0 × 93.6 mm; on cliff above S. shore of mouth of Layou River ; H. H. Hobbs Jr & F. A. Chace coll. 9.III.1964 and det.; USNM 126937 About USNM ( See Fig. 6F View FIG ) • 1 ovigerous ♀ 67.2 × 92.5 mm; coll. J. G. Ramage; 1888.26; NHM 1888.26. Barbados • 1 ♂ 60.0 × 85.4 mm, 1 ♀ 63.2 × 86.6 mm (dark red morphs); Crane Hotel , St. Philip; coastal cliffs; 13°10’25.96”N, 59°44’65.73”W, 28.09.2019; Parasram coll. and det.; BLSZ 059 . Curaçao • 1 ♂ 37.8 × 51.4 mm; Caracas Bay , Hato [Hato caves]; 28.IV.1920; C. van der Horst; USNM 56879 About USNM .

Colombia, Isla de la Providencia • 4 ♀ 63.4 × 83.9 mm, 66.7 × 89.8 mm, 60.0 × 80.6 mm, 55.2 × 71.5 mm; R / V Albatross ; S. I. Smith det.; USNM 7343 About USNM (See Fig. 6G View FIG ) .

Bahamas • 1 ♀ 59.0 × 81.0 mm; dry, damaged; as Gecarcinus ruricola ; MNHN-IU-2000-12496 (= MNHN-B12496 ) .

TYPE LOCALITY. — The previous statement of ‘America’ by Linnaeus (1758) as type locality must be replaced by the place of origin of the neotype, namely Cuba.

DESIGNATION OF A NEOTYPE

In order to fix the taxonomic identity of Gecarcinus ruricola , we undertook the necessary steps to trace the type of Cancer ruricola Linnaeus, 1758 , first by consulting the Catalogue of the ‘Linnaean collection’ held at Uppsala University, and then by contacting the Linnean Society of London, which provided us with a list of ‘Linnaean type specimens’, including Crustacea, deposited at that institution ( Wheeler 1983). No specimen with this name has been found in these two institutions and therefore no name-bearing type specimen is considered to be extant ( ICZN 1999: Article 75.1). In order to define and typify G. ruricola objectively by a single specimen, a neotype is designated here. As the neotype must come “as nearly as practicable from the original type locality” ( ICZN 1999: Article 75.3.6), in our case from ‘America’, a Cuban representative ( Figs 2 View FIG ; 3 View FIG A-F) is well suited to be a candidate for the neotype since Linnaeus had received material from various places in America, including this island, for his Systema Naturae.

DIAGNOSIS

Like the genus Gecarcinus new status, which is represented by the one and only species G. ruricola .

REMARKS

According to Hartnoll et al. (2006a: table 6), in San Andrès, the species is heterochelic, with no preferential handedness. The larger size of male chelae is small compared to other gecarcinoid species. Growth patterns of the chelae result in modest levels of heterochely and sexual dimorphism. This suggests that both sexes play roles of similar dominance levels during intraspecific interactions. In the material examined, the chelae of male G. ruricola are subequal, without marked heterochely and heterodonty ( Figs 1A View FIG ; 3A, B View FIG ; 4B View FIG ; 10D View FIG ; 17 View FIG ; 18 View FIG ), however with exceptions (see Fig. 1B View FIG ). There appears to be no genetic predisposition for right-handedness in Gecarcinus ruricola .

During the night and when disturbed in their burrows during the day, Hartnollius lateralis n. comb. and H. quadratus n. comb. are known to produce sounds ( Klaassen 1973: figs 1-5, and Abele et al. 1973: fig. 1, respectively) by friction of the merus of the cheliped against the subhepatic region of the carapace, which bears a number of oblique rows of striae (pars stridens) ( Figs 12A View FIG ; 14A View FIG , respectively). However, in the case of Gecarcinus ruricola , which has similar striae in the same region ( Figs 2B View FIG ; 4D View FIG ; 18B View FIG ), this type of communication does not seem to have been reported.

SIZE

Besides Gecarcoidea natalis (Pocock, 1888) View in CoL , from Christmas Island, Indian Ocean, which can exceed 120 mm cw (see Green 1997), Gecarcinus ruricola View in CoL reaches very large sizes, with a modal size of 97-110 mm cw and a maximum recorded of 123 mm cw ( Van der Hoeven & Walters 1998; Hartnoll et al. 2006a: figs 2, 3). It is one of the largest American gecarcinids, making it a ‘museum piece’ ( Richmond 2003) ( Figs 1 View FIG ; 2 View FIG ). The mean carapace width of all measured Hartnollius lateralis n. comb. was approximately half that of all measured G. ruricola View in CoL , whereas the mean fronto-orbital distance of H. lateralis n. comb. was less than half that of G. ruricola View in CoL ( Britton et al. 1982: fig. 3), i.e., the carapace of G. ruricola View in CoL lateral to the orbits is proportionately larger than the corresponding area of H. lateralis n. comb. The mean size of adult G. ruricola View in CoL is known to differ among the Caribbean Islands: for example, throughout the Grand Cayman both sexes are smaller in terms of body size than other populations in the Caribbean and males are larger than females (see below, Biology); by comparison, H. lateralis n. comb. shows an increase in mean size from eastern to western localities. G. ruricola View in CoL has by far the most inflated carapace.

COLOUR

Phenotypic plasticity in colour patterns is very often observed in land crabs, and multiple morphs can be recognised in the same species. Gecarcinus ruricola is known to exhibit extensive colour polymorphism, with at least four main colour morphs: black, red or purplish, yellow and green, some with subpatterns, as follows. Martinique: carapace and legs intense purplish or dark morph ( Fig. 17A View FIG ); Dominica: black morph that has a rich purple dorsal surface of carapace, with reddish overtones and various spots ( Fig. 18H View FIG ) ( Chace & Hobbs 1969), and yellow morph ( Fig. 18G View FIG ); Saint-Barthelemy: a green morph mixed with other colours ( Fig. 18A View FIG ), a red morph ( Fig. 18B View FIG ) also an intense purplish morph or black morph ( Fig. 18C View FIG ); Anguilla:a mixed colour morph ( Fig. 18E View FIG ), a black morph ( Fig. 18F View FIG ) and a yellow morph ( Fig. 18D View FIG ); Grand Cayman: black morph, and subpatterns. The mesial lobe of infraorbital margin is very often, whatever the island and the morph, intensely red ( Figs 17 View FIG ; 18 View FIG ). In Puerto Rico, G. ruricola has different colours on the carapace, chelae, and legs: some carapaces have varying intensities of purple, from dark to light, blue, and varying intensities of yellow/orange ( Rodríguez-Fourquet et al. 2025: fig. 6). The Grand Cayman ‘black crab’ exists in three different colour morphs ( Stensmyr et al. 2008: fig. 1A, D), but this information must be corroborated because the figure E of the same authors seems to belong to Hartnollius lateralis n. comb.

In Cuba, Gecarcinus ruricola displays two different patterns: the black and light tan or yellow morphs ( Chace 1940: 53). A study of colour polymorphism in the G. ruricola from western Cuba, in the Parque Nacional Ciénaga de Zapata (one of best bird watching areas in the world) has identified two different patterns: black and yellow morphs, without any statistically significant difference for the frequency of the yellow colour neither between sexes nor between years; and the relation cheliped-body weight compared between both colours gave similar result ( Acevedo 1989: figs 2-4, table 1). A striking but variable red/purplish morph is observed in Cuban G. ruricola from La Blanquilla ( Scelzo & Varela 1988: fig.4), which can lead to confusion with Hartnollius lateralis n. comb. ( Fig. 19 View FIG ). A mixed colour morph is also present in Cuba ( Fig. 17B View FIG ).

For Gecarcinus ruricola View in CoL there are no studies focusing on the colour patterns and the significance of the colour diversity. Such a study has been conducted, for example, on Cardisoma guanhumi View in CoL from northeastern Brazil, where the four identified colour patterns could be clearly related to the crab’s stage of development (growth size) and sexual maturity, with the smallest individuals being bright orange and the sexually mature adults ranging from brown to blue ( Silva et al. 2014). It is also possible that colour patterns may change depending on seasonality and the current state of the individual (stress, endogenous rhythms or even temperature variations). They could also be related to osmoregulatory and respiratory physiology, response to desiccation, moult cycle and mating behaviour ( Reid et al. 1997; Silbiger & Munguia 2008).

In comparison, in Johngarthia lagostoma View in CoL from Trindade Island ( Brazil), colouration varies depending on individual size, sex and ecological processes related to differential occupation of available habitats: there are three colour types (black, purple and yellow), with black crabs being exclusive and predominant in the smaller size classes; then, yellow crabs dominate throughout ontogeny, while purple individuals are less frequent. Crabs of all three colour types are present in both sexes, and the frequency of each type are similar in males and females. Black and purple crabs primarily occupy hill areas, whereas yellow crabs predominate throughout the island. Camouflage by background matching appears to be particularly important for small black crabs at recruitment (beach sand) and resident areas (hills vegetation and soil), where individuals exhibit higher colour matching types in both sexes. The frequency of each type, their brightness and colour metrics are similar between beaches and resident areas (hills vegetation and soil), where individuals exhibit higher colour matching ( João et al. 2023).

VERNACULAR NAMES

Gecarcinus ruricola is known as the ‘black land crab’, ‘purple land crab’, ‘red land crab’, ‘mountain land crab’, ‘zombie crab’, ‘Halloween Krabbe’, and ‘blue crab’. It may be given the surname of ‘tourlourou’ or ‘touloulou’ (as in the French Antilles, see Fig. 4A, B View FIG ), as well as other species of Gecarcinidae , e.g. Hartnollius lateralis n. comb. (see below, Identity of land crabs synonymised with Gecarcinus ruricola or G. lateralis in the literature).

For the pre-Linnaean nomenclature of gecarcinids, see Holthuis (1959) in his C rustacea Decapoda of Suriname. Holthuis (1959: 7) explains that Labat (1724: 47-53) described the species ‘Tourlouroux’ ( Gecarcinus spec. ), ‘Crabes violettes’ (= Gecarcinus spec. ), ’Crabes blanches’ (= Cardisoma guanhumi Latr. ), and that the Suriname species identified by Fermin (1765) as ’Crabes violets’, ‘Crabes blancs’ are not the species referred to by Labat but are Ucides cordatus (Linnaeus, 1763) and Ocypode quadrata (Fabricius, 1787) , respectively. In fact, only Cardisoma guanhumi is found in Suriname, and its distribution area extends from Brazil to Bermuda, Bahamas, Southern Florida and the West Indies ( Holthuis 1959: 259, pl. 12).

UPDATED GEOGRAPHICAL DISTRIBUTION

Gecarcinus ruricola View in CoL is found without discontinuity throughout much of the Caribbean, only on islands. From the Bahamas and Cuba in the west it extends through the Greater and Lesser Antilles to Barbados in the east, i.e., Jamaica, Hispaniola, Cayman Islands, St. Croix, Saint Martin, Saint-Barthelemy, Saba, Montserrat, Guadeloupe, Martinique, Dominica, Barbados (see Hartnoll 1988a: fig. 2.6). Outlying populations occur on Curaçao, Aruba, Bonaire, Blanquilla, and in the western Caribbean in the Swan Islands off Honduras, Half Moon Caye of the Belize Barrier Reef; and also the Archipelago of San Andrés, Old Providence and Santa Catalina, off the Caribbean coast of Colombia ( Powers 1977; Abele & Kim 1986; Hartnoll et al. 2007). It is common on some Caribbean islands, but less in others.

There were very few records of Gecarcinus ruricola View in CoL for continental America and, moreover, they have not been confirmed ( Hartnoll & Clark 2006). The record from Florida ( Rathbun 1918: 355) is only supported by specimens from Loggerhead Key in the Dry Tortugas, where the species was considered rare ( Powers 1977; Bliss et al. 1978). The location in southeastern Florida by Chace & Hobbs (1969) and Keith (1985) has not been confirmed by other sources, and no specimens or locations are cited ( Hartnoll et al. 2006a). Our examination of the NMNH material leads to the elimination of G. ruricola View in CoL from continental America. In fact, Rathbun’s record from ‘Florida’ (cited e.g. by Chace & Hobbs 1969; Keith 1985; Luque 2017) does not apply to G. ruricola View in CoL . The records ‘nS Am’ and ’E Fla’ in Felder et al. (2009: 1088) are also erroneous. The two males and two females from the Florida Keys, Loggerhead Key (USNM 71219) ( Fig. 5A, B View FIG ) were misidentified as G. ruricola View in CoL by Rathbun (1918) and are in fact typical Hartnollius lateralis n. comb. Similarly, references to ‘Nicaragua’ mentioned by Chace & Hobbs (1969) and Keith (1985) but not confirmed by other sources, and the absence of citations of other specimens from this location (see Hartnoll et al. 2006a) correspond to a misidentification. Our examination of the material ( two males) ( Fig. 5C, D View FIG ) from Nicaragua, Greytown (USNM 74612), labelled as Gecarcinus ruricola View in CoL by Rathbun, but later annotated “looks like to me G. lateralis ” by H. L. Carson, and reidentified as G. lateralis by F. H. Barnwell, shows that these crabs are indeed Hartnollius lateralis n. comb. Due to the absence of G. ruricola View in CoL in continental America here confirmed, G. ruricola View in CoL would be restricted to the Caribbean Islands and would be an insular species (see Garth 1976 for comments on insular species), which makes previous accounts of its distribution inaccurate.

Note that a crab from Isabel Island, Sinaloa, Mexico, a male 66.0 × 94.0 mm, W. C. Swettt coll. (‘red land crab’), 19.III.1933, Rathbun det. (USNM 139315), was misidentified and, according to our examination, is in fact the eastern Pacific land crab Johngarthia planata (see Samaniego-Herrera & Bedolla-Guzmán 2012; Perger 2019). The report of G. ruricola in the North of Mexico by Leija-Tristán (1985) is most likely Hartnollius lateralis n. comb.

The mention of ‘ Ecuador (Cano, Nobili)’ by Rathbun (1910: 612; 1918: 357) regarding the distributional range of Gecarcinus lateralis is somewhat confusing because the Gecarcinus of Cano (1889: 101, 227) and Nobili (1901: 46), both from Ecuador, are cited by these two authors as G. ruricola . This formulation by Rathbun (1910, 1918) is explained by the fact that she attributed these G. ruricola specimens from the Pacific coast to G. lateralis . The G. ruricola of Cano and Nobili were later assigned to G. quadratus by Garth (1948: 59). The crab of Nobili (1901) gave its name to G. nobilii Perger & Wall, 2014 , now Hartnollius nobilii n. comb. (see Perger & Wall 2014). Although Perger & Wall (2014) do no mention the G. ruricola of Cano (1889: 101, 227) from the same region, Ecuador, it is likely that this specimen also belongs to Hartnollius nobilii n. comb.

PHENOTYPIC VARIATIONS

We assembled abundant material of Gecarcinus ruricola , a species widespread in many and diverse Caribbean islands, but also reported on the continent, to detect possible intraspecific variability or the presence of cryptic species.Since the few previous records of G. ruricola from continental America had never been confirmed, it was necessary to review this issue in depth. Our examination has evidenced that the continental species assumed to be G. ruricola were in fact Hartnollius lateralis n. comb., see above Updated geographical distribution; and Figure 5 View FIG .

The main variation observed concerns the mxp3 (when firmly applied against the buccal wall) and the level reached by the extremity of the sterno-pleonal cavity in relation to the thoracic sternal suture 2/3, which somewhat varies, being either straight or slightly concave ( Fig. 6 View FIG ). An extreme condition, with maximum anterior extension of the mxp3 and complete coverage of the buccal cavity, is found in Gecarcinus ruricola from Haiti.We examined two lots: one from the NMNH (USNM 1513693, with one male and one female, both small); and another lot from the NHM (NHM 1967.7.1.80-85 with six large males) from the vicinity of Haiti, namely from Navassa Island (‘Isle de la Fortune’). These Haitian individuals are characterised by a remarkable feature, that of having their mxp3 reaching the frontal border, and even exceeding it in some, and the meri on each side being entirely joined medially (except at the level of the mandibles), with an irregular latero-internal margin ( Fig. 6 View FIG A-C). The two external maxillipeds form a complete cover to the more internal mouthparts, with only part of the mandibles and some small portions of other maxillipeds being exposed. Therefore, the latero-external margin of the merus is very close to the infraorbital ridge. A character that appears concomitant is the close proximity of the extremity of the sterno-pleonal cavity to the thoracic sternal suture 2/3 ( Fig. 6 View FIG A-C). When compared in all the Haitian specimens we have examined, the mxp3 merus is more or less oval, more or less elongated, and more or less obliquely directed, which demonstrates that this structure is somewhat variable, even among crabs within a population that appears homogeneous. See below under Gecarcinus depressus Saussure, 1857 .

Considering Gecarcinus ruricola from other Caribbean islands, it is clear that the condition of mxp3 is variable. Forward extension and covering of the buccal cavity are observed in crabs from other localities than Haiti, to varying degrees. For example, the small male and female from Guadeloupe collected during Karubenthos 3 Expedition ( Fig. 5A, B View FIG ) show a similar extension of the mxp3 ( Fig. 6D, E View FIG ): the merus reaches the front, and its internal border is slightly concave; each merus joins that of the other side; the extremity of the sternal cavity reaches the sternal suture 2/3. The pattern is the same in G. ruricola from Martinique ( Fig. 17A View FIG ). The extension is quite pronounced in a male G. ruricola from Dominica ( Figs 6F View FIG ; 18G View FIG ). In a small male cw 75.9 mm ( USNM 2065) and two larger males 60.0 × 85.3 mm, 63.1 × 86.5 mm ( BLSZ 059) from Barbados, as well as in a male 66.6 × 93.8 mm ( NHM 1888.26) from St Kitts, the mxp3 are much extended and leave only a very short space between the anterior margin of merus and the front. In a male from Jamaica, the merus reaches the antennules, as in the large male cl 67.0 mm represented by Chace & Hobbs (1969: fig. 66) where the merus covers the epistome and most of the antennular cavities. In specimens of Cayman Islands, the merus reaches either the antennules or only the epistome. On Providencia Island, Colombia, all four females examined have the anterior part of the mxp3 reaching only the epistome but to a variable extent ( Fig. 6G View FIG ). In the material from Cuba, individuals have their mxp3 reaching either the level of the front ( Figs 17B View FIG ) or the antennules or only that of the epistome as in the neotype ( Figs 2 View FIG C-D; 10A); in another specimen ( Fig 6H View FIG : see right mxp3), the space between the merus and the frontal margin is more or less pronounced.

As these are only occasional and isolated examples, or at least studies involving a far insufficient number of individuals, the above remarks may be biased and may not represent the overall morphology of the external mouthparts in all individuals in the populations of the countries considered. The first male gonopod is known to be the most reliable character for taxonomic decisions (see Toledano-Carrasco 2019: figs 14-19, the numerous figures of H. lateralis n. comb. and H. quadratus n. comb., as Gecarcinus ), but, despite careful examination of the G 1 in Gecarcinus ruricola crabs from various islands, we did not detect any possible variation, at least under a binocular microscope.

The phylogenetic tree based on the mitochondrial genes COI and 16S ( Fig. 16 View FIG ), as well as the COI-based genetic distance matrix ( Table 3 View TABLE ), do not reveal any significant differences between the samples from Cuba and Guadeloupe. We therefore assume that Gecarcinus ruricola is a species with intraspecific variability and whose interbreeding populations are reproductively compatible.To corroborate this hypothesis, it would be interesting to include more specimens from different localities in a more in-depth study of the species. It is possible to assume that actually or potentially interbreeding populations are reproductively compatible with other populations The pelagic lifespan of G. ruricola is likely to be of 40-50 days and, if water currents are conservatively paced at 1-2 knots, then this would give a potential dispersal range of between 2000 to 4500 km. This potential larval dispersal (see Garth 1976) is sufficiently strong to indicate potential intermixing between Caribbean populations of the species ( R. Hartnoll, pers. comm.). We currently have - with material insufficiently representative of a population – no decisive morphological argument in one direction or the other: for example, all Haitian specimens examined from three different lots exhibit a similar morphology of the mxp3 ( Fig. 6 View FIG A-C) but, on the other hand, the specimens from Cuba show a mxp3 merus either extending to the front ( Fig. 17B View FIG ) or reaching only the antennules, or the epistome only ( Fig. 6G View FIG ). Could the low phenotypic disparity observed, which, at this stage, does not, in our opinion, imply taxonomic changes, be related to genetic divergence? The DNA analyses (although limited) of individuals from the Caribbean islands does not demonstrate the existence of cryptic species in a possible G. ruricola complex.

BIOLOGY

Gecarcinus ruricola View in CoL inhabits damp, shaded forest areas or dry upland habitats, retiring into rock crevices or sheltering between tree roots or hiding under fallen trees, sometimes muddy beaches, which distinguishes it from the other three species of Hartnollius n. gen. (see Wolcott 1988: fig. 3.1, as Gecarcinus View in CoL ). The population biology of G. ruricola View in CoL , studied in the western Caribbean, particularly on two islands of the San Andrés Archipelago, San Andrés and Old Providence/Santa Catalina Islands ( Hartnoll et al. 2006a) View in CoL , reveals that the ‘black land crab’ is the most terrestrial of gecarcinids in the Caribbean (some of endemic Jamaican sesarmids are more terrestrial overall). It feeds on fruits, mushrooms and other organic matter from the forest.

In Dominica, G. ruricola View in CoL is found several kilometres inland from the sea, up to 300 m ( Chace & Hobbs 1969), and up to 1000 m in Jamaica ( Britton et al. 1982) and in the San Andrés Archipelago ( Hartnoll et al. 2006a); it can even live several kilometres inland ( Wolcott 1988). G. ruricola View in CoL (‘black land crab’) is found throughout Grand Cayman (such as Cardisoma guanhumi View in CoL ): males reach a larger maximum size than females, both sexes are smaller in terms of body size than other populations in the Caribbean (it may be possible the populations on Grand Cayman reach sexual maturity at an earlier stage and smaller size than other geographic locations), and the reproductive migration season extends over three months on Grand Cayman ( Tedford 2018). The lateral regions of the carapace are inflated to accommodate the highly modified respiratory structures.

Its biometric characteristics, distribution and activity have been compared to those of Hartnollius lateralis n. comb. by Britton et al. (1982, as Gecarcinus lateralis ). Burrowing is somewhat incidental in G. ruricola , whereas H. lateralis n. comb. is an active burrower ( Wolcott 1988: fig. 3.9) and even moults within its burrow ( Weitzman 1963; Bliss 1968; Bliss et al. 1978, as G. lateralis ). G. ruricola is frugiforous and mainly nocturnal ( Rodríguez-Fourquet et al. 2025), except during the breeding migration, whereas H. lateralis n. comb. can demonstrate striking diurnal activity, for example in the Cayman Islands forest ( Britton et al. 1982, as G. lateralis ) and is mostly herbivorous/omnivorous ( Linton & Greenaway 2007: table 3, as G. lateralis ), sometimes cannibalistic ( Wolcott & Wolcott 1984, as G. lateralis ). Carson (1967), Carson & Wheeler (1967) and Stensmyr et al. (2008: fig. 1, as G. ruricola and G. lateralis ; see also Stensmyr & Hansson 2007, as G. lateralis ) described the symbiotic relationships of G. ruricola (and also H. lateralis n. comb.) with drosophilids in the West Indies (see also Bright & Hogue 1972: table 1, as Gecarcinus ) and in Puerto Rico ( Rodríguez-Fourquet et al. 2025: fig. 7, as Gecarcinus ruricola ). Protists have been found in the digestive tract of H. lateralis n. comb. ( Perger et al. 2022).

Gecarcinus ruricola and Hartnollius lateralis n. comb. are sympatric in many areas of the Caribbean. Britton et al. (1982, as Gecarcinus lateralis ), who conducted comparative biometric analyses, habitat preferences, activity patterns and other biological data on these two species, highlighted the paucity of literature on G. ruricola within its range (in contrast to the extensive literature on H. lateralis n. comb.; see under that name), despite it is one of the most conspicuous terrestrial crustaceans, captured and used as food. The increasing presence of human activities in the Caribbean may deprive G. ruricola of suitable habitat and thus reduce its numbers.

The study of the reproductive biology of Gecarcinus ruricola in the San Andrés Archipelago by Hartnoll et al. (2007) provides extensive details on breeding females, annual breeding migration, egg laying (migrating crabs are mostly females with predominance of ovigerous females with the eggs carried under the pleon; some females mate and lay eggs on the landward side, others on the seaward side (see Fig. 21A View FIG ), migrating females on average are larger than migrating males), fecundity and irregular recruitment. The megalopa of G. ruricola is the most terrestrially adapted megalopa described to date for locomotion on land: it is the returning stage from the sea to the terrestrial habitat ( Hartnoll & Clark 2006: 162, figs 3-9, table 2). There are sometimes extensive land invasions by megalopae, with pink mass of megalopae crossing the landward side of the coast, a hasty moulting to the first crab and swarming into the forest. But such an invasion is not an annual event. The megalopa is the stage which invades land and normally travels overland some distance before moulting; the migration of berried females to the sea varies in timing and intensity from year to year, with, however, a substantial migration each year ( Hartnoll & Clark 2006: 162, fig. 2; Hartnoll et al. 2014: 532, fig. 1). A similar land invasion by megalopae occurred in Jamaica in 2006 ( Aiken & Pal 2009). And, in Cuba, crabs (red, yellow or black) sometimes emerge by the millions and head towards the sea to deposit their fertilised eggs in the water, mating having previously taken place in underground burrows.

In Puerto Rico, where site fidelity is present (except during migration), only female migration has been observed, meaning that copulation occurs far from the shore and in the forests, which males therefore do not abandon ( Rodríguez-Fourquet et al. 2025). If this is confirmed, there would be a notable difference with land crabs such as the ‘red crab‘ Gecarcoidea natalis (Pocock,1888) on Christmas Island, in which males and females migrate together to the sea and mate there, then the males return to their main residence, while the females remain on the shore to lay their eggs and release them in the sea, before heading towards the forests; a mass recruitment is observed approximately every five years ( Hicks 1985; Hicks et al. 1990).

ROLE OF GECARCINUS RURICOLA AND ITS STATUS

AS AN ENDANGERED SPECIES

As other gecarcinid land crabs, Gecarcinus ruricola is an ecosystem engineer and plays an important role in nutrient recycling and seedling propagation in coastal forests. Given the predicted future decline in precipitation for the Caribbean, the effects of dehydration on feeding preferences of G. ruricola were investigated on the Eleuthera Island ( Bahamas) by McGaw et al. (2019).

Gecarcinus ruricola View in CoL is a major source of protein and economic subsistence in many countries. It is known to have an extraordinary flavour. It is a popular food item, harvested on many Caribbean islands and offered live in markets ( Burggren & McMahon 1988: fig. 3.12B). According to Carson (1974: 3518), “relentlessly hunted down in the populated parts of its range, it remains today principally on small, isolated islands”. In Puerto Rico, the species is uncommon, and its harvest is prohibited, suggesting that other factors are affecting the population; G. ruricola View in CoL is classified as vulnerable by Puerto Rico’s Department of Natural and Environmental Resources ( Rodríguez-Fourquet et al. 2025).

In the San Andrés Archipelago, Colombia, on the tiny island of Providence in the southwest Caribbean about 140 miles east of, Bluefields, Nicaragua, Gecarcinus ruricola View in CoL , the ‘Cangrejo Negro’ or ‘black land crab’ ( Fig. 21 View FIG ) is a cultural symbol of the traditional patrimony, a figure in folklore, and plays an important role within the socio-economic structure of the local demography. Crabs of this species are a major local food source: its extraction and commercialisation is considered the third tier of the economy in Providencia (and also Santa Catalina), because approximately 139 families depend exclusively on black crab commercialisation to survive. Due to indiscriminate and illegal hunting, overexploitation, forest reduction, predators and difficulties in surviving during breeding and migration periods, G. ruricola View in CoL is one of the endangered species of these islands. As a result of the glaring lack of information on Gecarcinus ruricola View in CoL , the Final Report in April 2005 of the Darwin Initiative for the Survival of Species launched the project “Sustainable Management of the Black Land Crab, Gecarcinus ruricola View in CoL , Colombia (162/11/015)”, which, for example, supported the papers of Hartnoll et al. (2006 a, 2007) on the biology and reproduction of this species in San Andrés. According to Baine et al. (2007), the exploitation of G. ruricola View in CoL in San Andrés for human food is so extensive that the Colombian government has established closed fishing areas, closed seasons, and minimum catch sizes.

The ‘Providencia Black Crab Presidium’, created to ensure the preservation of a marine and coastal ecosystem and the survival of species that represent an important source of income, is supported by IFAD (International Fund for Agricultural Development) and the European Union, with the collaboration of several strategic local partners (see Slow Food Foundation for Biodiversity, Providencia Black Crab). On April 1, 2024, the CORALINA Corporation [for the Sustainable Development of the Archipelago of San Andrés, Old Providence and Santa Catalina], “announced to all inhabitants of San Andrés Providencia and Santa Catalina, that from April 1 to July 31, the ‘black crab’ ban period begins, in accordance with resolutions 156 of 1993 and 1132 of December 30, 2005, for this reason the appropriation, access, capture, possession, extraction, transportation, commercialization or in any other way, the use of the species or derived products is prohibited.”

San Andrés natives are known as ‘black crabs’, and sociologists have coined the term «crab antics» to refer to West Indian cultural behaviours (see Darwin Initiative for the Survival of Species, a UK government grants scheme, notably for biodiversity conservation). The ‘Crab antics’ (i.e., the antics done by the crabs) in San Andrés and Providencia is a metaphor based on the observation of fishermen catching crabs and putting them in an open basket or barrel: the crabs quickly pull down any crab that tries to get out of the basket on its own; if they had cooperated, they could have easily escaped from the basket, but they did not: the lack of cooperation leaves everyone at the bottom of the basket. For a discussion of ‘crab antics’, see Wilson (1973, 1995, 2017). ‘Crab barrel syndrome’ (CBS) is similar: no crab can actually get out of the basket, and a person with CBS does not want to see anyone progress except for himself ( Uzum & Ozdemir (2020), and ‘Crab mentality’ or ‘crab theory’ refers to successful individuals that are seen as a threat by those who want to maintain their position and power, ensuring the collective demise ( Tagle 2021).

Gecarcinus ruricola is threatened in the Lesser Antilles by rats ( Pascal et al. 2004).

PHILATELY

Gecarcinus ruricola View in CoL is represented on a multitude of postage stamps from West Indies, notably Cuba, and other Caribbean countries ( Omori & Holthuis 2000, 2005). The species was featured on two African postage stamps (Tanzanian and Ugandan stamps) for the International Year of the Ocean in 1998, under the name ‘mountain crab’.

ON THE IDENTITY OF LAND CRABS SYNONYMISED

WITH GECARCINUS RURICOLA OR G. LATERALIS

IN THE LITERATURE

Ocypode ruricola Latreille, 1803

Latreille (1803: 35 and footnote) described Ocypode ruricola with the following features: carapace regularly domed, without edge; dorsal prints short, confused; carpus and palms little ornamented; tarsi with spiny edges; found ‘in America between the two Tropics and in their neighbourhoods, perhaps not living further than the neighbouring places of the Line (the Equator)’. Regarded as Gecarcinus ruricola View in CoL by H. Milne Edwards (1837 a: 26) and Young (1900: 239, as Geocarcinus ruricola ), it would be Cardisoma guanhumi View in CoL according to Rathbun (1918: 341); nevertheless, the figures of Latreille (1803: pl. 44 fig. 2), copied from Herbst (1783: pl. 4 fig. 37, as Cancer ruricola ), represent the true G. ruricola . There is no crab labelled Ocypode ruricola in the MNHN collection.

Ocypode tourlourou Latreille, 1803

In the same paper, Latreille (1803: 36) established Ocypode tourlourou from Santo Domingo, for a large species, generally pale yellow, almost whitish, sometimes washed with reddish and presenting the following characters: chelipeds practically unarmed; major cheliped on the right with the fingers bearing a molariform tooth, and a smooth carpus with a small internal tooth; ventral surface with black setae (‘poils noirs’); and merus of the legs unidentate. Latreille added that the only figure of Seba [ Cancer View in CoL terrestris] that is suitable for this species is that of t. III, pl. 20, fig. 5 (see Seba 1734 -1765). This species, not mentioned by H. Milne Edwards (see 1837a: 26), was considered, without further explanation, to be a true Gecarcinus ruricola View in CoL by Rathbun (1918: 352), Chace & Hobbs (1969: 200) and Türkay (1970: 336) [who does not mention the Latreille’s O. ruricola View in CoL ]. No crab bearing the name Ocypode tourlourou is present in the MNHN collection.

‘Tourlourou’ is a popular term given during the First World War to infantry soldiers who wore a blue jacket and madderred trousers. Sailors arriving in the Antilles nicknamed the red crabs ‘Tourlourous’. ln French Guyana, ‘Tourloulou’ denotes any disguised and masked person, alluding to the expression ‘Tour le loup’, which refers to women wearing a mask and whirling while dancing in ballrooms ( Belfort 2013).

Land crabs in Fréminville (1835)

Fréminville (1835: 215) wrote: “Linnaeus was the first to characterize, under the name of Cancer Ruricola , the common Tourlouroux of the Antilles; and of all the descriptions that have since been made of this land crab, his is still the best; but nevertheless, his successors, either through negligence or lack of opportunity to observe better, have reported and confused with his Cancer Ruricola , two or three distinct species which we will make known below.” Fréminville (1835: 215, 216, 217) later wrote: “We are applied particularly to observing land crabs or Tourlouroux and we first noticed that among those understood to this day by naturalists under the names of Cancer Ruricola , Ocypoda Ruricola and Gecarcinus Ruricola , of which they are one and the same species, we could recognise them three distinct ones as Mr. Bosc had already suspected. It is therefore not surprising that the authors differ among themselves in the descriptions they give of the Tourlourou”. Fréminville retains the name of Ocypode Ruricole for the one of the three species “that is the most common and is the true Cancer Ruricola of Linnaeus”, and describes its morphology (too vaguely to be identified), its colour pattern and its biology (”lives in the woods and feeds there on leaves, fallen fruits and generally on plant substances”; never carnivorous unlike other gecarcinids; nocturnal; digs burrows; runs with such speed that it seems to glide rather than run, so that it is very difficult to catch, and rushes into the burrow, which serves as its retreat). An Editor’s note (p. 213) indicates that it is probably Cardisoma guanhumi .

Then, Fréminville (1835) lists four taxa:

1. The Ocypode Ruricole or common Tourlourou.

Ocypoda Ruricola, Fabricius, Bosc.

Cancer Ruricola Linnaeus.

Gecarcinus Ruricola , plates from the Encyclopedia.

See Bosc (1830: 252): “It is found in America, where it is known as Land Crab. There are probably several species confused under this name”.

2. The great Tourlourou. Ocypoda gigantea N. [i.e., Nobis]

This ‘dirty white’ crab (see Fréminville 1835: 221) is Cardisoma guanhumi , according to an Editor’s note (p. 213) and to Chace & Hobbs (1969: 195).

3. The red Tourlourou. Ocypoda rubra Fréminville (1835: 222) from Antilles.

According to the Editor’s note (p. 213), it seems to be the real G. ruricola . It was synonymised with Gecarcinus ruricola by Rathbun (1918: 352) without any comment, then by Türkay (1970: 336), Prahl & Manjarrés (1984a: 154), and Ng et al. (2008: 215). However, Ocypode rubra might not be Gecarcinus ruricola but could be G. lateralis (i.e., Hartnollius lateralis n. comb., see below), which is red and digs oblique, complex burrows near the shore. The fact that it “stands as a sentinelle near the opening, and runs very fast” leaves some doubt.

Ocypode agricola Reichenbach, 1836 (p. 230, 231)

(see Reichenbach 1828 -1836)

We attempted to locate the specimens from the Antilles that were used by Reichenbach (1836: 230) to establish Ocypode agricola . As was customary at the time, the species was described vaguely and summarily:carapace blood-red; sides raised; margins rounded; orbits round. It lives in holes, is nocturnal, and migrates to the sea and then to land. O. agricola was synonymised with Gecarcinus ruricola by Rathbun (1918: 352) without any comment, and later by Türkay (1970: 336) and Ng et al. (2008: 215). The species is rarely mentioned in the chresonymy of G. ruricola , except by some authors such as Chace & Hobbs (1969: 200), Prahl & Manjarrés (1984a: 154), Questel (2019: 26) and Schweitzer et al. (2023: 2). With the help of curators and researchers from various German institutions, we learnt that Reichenbach studied in Leipzig and that the remarkable collection of the “Zoologisches Institut Leipzig” is now part (at least) of the Crustacean collection in Dresden. It seems that three specimens in two lots (dry and partly in poor condition) from the Antilles bearing the name ‘ Gecarcinus ruricola ( Linnaeus, 1758) ’ and registered «Crustacea - SNSD» were found in the Dresden Collection: but, supposedly purchased later, in 1881, from Flesche, they would probably not be the original Reichenbach’s specimens, collected earlier (Andreas Allspach and A. Reimann, pers. comm.). Moreover, if the type of O. agricola was included in the Crustacean collection of Dresden, a town destroyed in 1945, it must be considered lost (A. Reimann, pers. comm). Although the crabs listed in the Catalogue of the old Leipzig Collection (started in 1870) are not registered as the syntypes of Ocypode agricola , we nevertheless give here some photographs (kindly sent by A. Reimann) of the three specimens from the Antilles (two lots): the mesial lobe of the infraorbital margin just joining front margin in all three specimens ( Fig. 7B, E, G View FIG ) indicates a true Hartnollius lateralis n. comb. ( Figs 10B View FIG ; 12B, C View FIG ; 19 View FIG ); although the anterior margin of mxp3 merus is not notched and is only barely concave, thus not really concordant, it is not distally triangular as in G. ruricola : it would be only a variation of H. lateralis n. comb. No specimens of Reichenbach appear to be part of the collection of the Leipzig University (Robert Klesser and Bernhard Detlef, pers. comm.).

Gecarcinus depressus Saussure, 1857 View in CoL

Saussure (1857: 305; 1858a: 439, pl. 2 fig. 14, a-c; 1858b: 23, fig. 11) established for two very small specimens from Haiti a new species, Gecarcinus depressus View in CoL , “due to the remarkable configuration of its maxillipeds which seems to indicate a special group within the genus Gecarcinus View in CoL ”, without any comparison with G. ruricola View in CoL , but with a detailed description, with characters as follows. The mxp3 merus is oval, much less wide than the ischium, does not narrow towards the front and barely narrows towards the back; its anterior margin is subnotched (‘subéchancré’), and the dactylus of the legs has four rows of spines. G. depressus View in CoL was synonymised with G. lateralis (under its former name, see below under Harnollius lateralis n. comb.) by Rathbun (1918: 355) without any comment, then by Chace & Hobbs (1969: 198), Türkay (1970: 337) and most authors. The suggestion by Miers (1886: 218, and footnote, as Geocarcinus depressus ) that this species might not be distinct from Gecarcinus lagostoma View in CoL , now Johngarthia lagostoma (H. Milne Edwards, 1837) View in CoL , cannot be accepted because the mxp3 merus is subnotched on the anterior margin in G. depressus (in fact, it appears only very sligthly concave in Saussure’s figures), whereas it is clearly notched on the lateral margin in J. lagostoma View in CoL (see Türkay 1970: fig. 5c, as Gecarcinus ( Johngarthia) lagostoma View in CoL ). Young (1900: 240, as Geocarcinus depressus ) provided a description based on Saussure and considered the species valid. In any case, the species Gecarcinus depressus View in CoL deserves close scrutiny.

According to Hollier (2018: 294; see also Hollier & Hollier 2012), two small male syntypes of Gecarcinus depressus from Haiti, first dry then transferred into alcohol, are deposited at the MHNG. The two specimens are stored in separate tubes in the same jar, with two typewritten labels indicating that Türkay revised the specimens in 1972 and identified them as G. lateralis lateralis ( Türkay 1970: 337) . But a careful examination of the photographs of these two syntypes ( one male 19 × 23 mm, another one damaged), kindly sent by J. Hollier, poses a problem: the two syntypes belong to two different species. Specimen MHNG-ARTO-16403, a male c. 23.1 × 18.7 mm ( Fig. 8 View FIG A-D) is not G. lateralis but is quite similar to G. ruricola in that the mesial lobe of the infraorbital margin is overlapped by the frontal edge (versus only joined in G. lateralis ); the mxp3 merus (somewhat asymmetric) is oval and rather close to the front, with an unnotched anterior margin and a barely notched internal margin (versus anterior border emarginated in G. lateralis ); and the tip of the male sterno-pleonal cavity extends to the thoracic sternal suture 2/3 (versus the two are distant in G. lateralis ). The small exorbital tooth present ( Fig. 5 View FIG ) is also found in our smallest specimens of G. ruricola from Haiti ( Fig. 6C View FIG ). These characters are rather those of G. ruricola . Although the mxp3 merus of G. depressus ( Fig. 8C View FIG ) is not as narrow distally and not as obliquely directed as in our Haitian G. ruricola specimens ( Fig. 6 View FIG A-C), even in the smallest examined ( Fig. 6C View FIG ), it remains quite distinct from that of G. lateralis (under its former name, see below under Harnollius lateralis n. comb. ( Figs 10B View FIG ; 11B View FIG ; 12A, B View FIG ). Given the variations observed in the G. ruricola examined, it is possible that G. depressus is pro parte a young G. ruricola .

Conversely, specimen MHNG-ARTO-16404, a male c. 17.6 × 14.6 mm, with a damaged carapace, has the mesial lobe of the infraorbital margin just joining the frontal margin ( Fig. 8E, F View FIG ); the right mxp3, in place, is smaller, very far from the front; the merus is small, its anterior margin is slightly subnotched whereas its internal margin is slightly bowed; the left mxp3, detached and photographed at higher magnification, shows a clear notch on the anterior margin ( Fig. 8F, H View FIG ). This is the specimen whose Saussure (1858a: 439, pl. 2 fig. 14, a-c; 1858b: 23, fig. 11) depicted the mxp 3 in the same way on several occasions, and which, in this respect, most resembles G. lateralis (under its former name; see under Hartnollius lateralis n. comb.), although studied and compared by Saussure on the same page.

If genomic sequencing were to demonstrate the existence of genetically distinct populations in Haiti (simple working hypothesis), the specific name depressus could apply. See above, Phenotypic variations.