Hartnollius lateralis (Paula & Rodríguez & Atzimba & Toledano-Carrasco, 2025)

Paula, Danièle Guinot, Rodríguez, Paula A., Atzimba, Moreno I. & Toledano-Carrasco, Atzimba, 2025, The charismatic Gecarcinus ruricola (Linnaeus, 1758), type species of Gecarcinus Leach, 1814, with a neotype designation and genetic data, and new generic assignment, Hartnollius n. gen., for the three remaining species of the genus (Crustacea, Brachyura, Gecarcinidae), Zoosystema 47 (16), pp. 261-314 : 286-291

Hartnollius lateralis (Fréminville in Guérin, 1832) n. comb.

( Figs 5 ; 9A ; 10B, E ; 11B ; 12 ; 13A, B ; 16 ; 19 ; Table 1)

Gecarcinus lateralis Fréminville in Guérin, 1832 (1829-1837): 7 and caption of pl. 5, fig. 1. — H. Milne Edwards 1837 a: 27; Atlas, pl. 18, figs 1-6. — Gerstaecker 1856: 144. — Saussure 1858a: 440. — Desbonne in Desbonne & Schramm 1867: 42. — Pocock 1889: 6. — Rathbun 1901: 14; 1910 pro parte: 591; 1918 pro parte: 355, fig. 161, pls 119, 120 (not material from Ecuador which is likely H. nobilii n. comb.); 1920: 19; 1921: 79; 1924: 19; 1933: 95, fig. 91, pl. 18f, 1-3; 1936: 388. — Verril 1908: 308, fig. 2. — Pearse 1916: 554. — Chace & Holthuis 1948: 26. — Bliss et al. 1966: 197-212; 1978: 111-152, figs 6, 7-11, 13-31, tables 1, 2. — Bliss 1968: 359, 360, 361, 362, 363, 366, 367, 369, 370, 374, 376 et seq., figs 2, 6, 7, 9, 10, 12, 14, 16-21, tables 2, 3; 1979: 385-41, figs 1-18, table 1. — Chace & Hobbs 1969: 198, figs 65, 67e-g. — Bright & Hogue 1972: 20. — Klaassen 1973: 73-79, figs 5, 6; 1975: 101-174, figs 1-6. — Powers 1977: 139. — Hopkins et al. 1979: 192-207. — Rodríguez 1980: 403, fig. 110, pl. 68. — Lemaitre 1981: 261. — Powers & Bliss 1983: 273 et seq. — Keith 1985: 274, fig. 12A. — Savazzi 1985: 147-153, figs 1A, 2, 3A, B, 4, 5A, B. — Abele & Kim 1986: 61, 661, 663, fig. b, d. — Scelzo & Varela 1988: 36, 48. — Martinez & Bliss 1989: 1-29. — Hernández-Aguilera et al. 1996: 92. — García et al. 1998: 27. — Guinot & Bouchard 1998: 669. — Venable 2004: unnumbered page and photo. — Carré 2005: 23. — Schubart et al. 2006: 195, table. 1. — Lalana et al. 2007: 82. — Ng et al. 2008: 215. — Felder et al. 2009: 1088. — Yokoyama 2013: 114, fig. p. 115. — Barro et al. 2013: 45. — Diez 2014: 83. — Questel 2014: 11; 2018: 15; 2019: 25 (and unnumbered photos), 33. — Hartnoll et al. 2014: 535; 2017: 949. — Seike & Curran 2014: 61, 63, 64, 67, 68 figs 2a-c, 3, 4, table 1. — Perger & Wall 2014: 97, figs 2A, B, 4H, I, 5A-C, 6A-C, 7, 8. — Hermoso-Salazar & Arvizu-Coyotzi 2015: 21. — Luque 2017: 153, fig. 3C, D. — Köhnk et al. 2017: 2018, fig. 18. — Diez & Espinosa 2018: 151. — Guinot et al. 2018: 568, 569. — Poupin 2018: 223; 2024: 138 . — N. K. Ng et al. 2019: 99 , fig. 2F. — Questel 2019: 25, unnumbered photos. — Parasram et al. 2021: 466 , fig. 8A-D. — Toledano-Carrasco 2016: 37-41; 2019: 16, figs 10A, 11A-D, 2A-J, 13A-I, 14A-N, 16A-N, 20A-F, I-Q. — Toledano-Carrasco et al. 2021: 215 , 216, 219 et seq., figs 1A, 2A-C, 3A, 4, 5, 7, 8, tables 1, 2, 3. — Vendeville et al. 2022: 193. — Hernández-Aguilera et al. 2022: 204, pl. 1, fig. F, table 1. — Parasram 2023: 125, fig. 3.8 A, B, C, D.

Ocypoda lateralis – Fréminville 1835: 224.

Gecarcinus (Gecarcinus) lateralis lateralis – Türkay 1970: 337, fig. 2af; 1974: 974, fig. 2a-f. — Willems 1982: 180-201, figs 1-10 (larval development). — Prahl & Manjarrés 1983: 32, fig. 2B; 1984a: 155, 158, 166, figs 3.2, 4; 1984b: 6, 8.

Nec Gecarcinus lateralis – Rathbun 1910 pro parte ( Ecuador): 591 (= Hartnollius nobilii ( Perger & Wall, 2014) n. comb.).

Nec Gecarcinus lateralis – Türkay 1987: 147, fig. 7 (= Hartnollius nobilii ( Perger & Wall, 2014) n. comb.).

Nec Geocarcinus lateralis – Young 1900: 239. (= Hartnollius quadratus ( Saussure, 1853) n. comb.). — Perger & Wall 2014: 97 (= Hartnollius quadratus ( Saussure, 1853) n. comb.).

TYPE MATERIAL. — Neotype (designation by N. K. Ng et al. 2019: fig. 2F). Guadeloupe • ♂ 36.7 × 47.2 mm; dry;; Beaupertuis coll.; as Gecarcinus lateralis ; MNHN-IU-2000-3758 (= MNHN-B3758 ).

OTHER MATERIAL EXAMINED — Guadeloupe • 1 ♂ (DAMAGED), 1 ♀ 23.9 × 27.6 mm; dry; M. Beaupertuis coll.; as Gecarcinus lateralis ; MNHN-IU-2000-3757 (= MNHN-B3757 ) • 22 ♂ 40.5 × 55.7 mm (photo), 40.4× 54.3 mm, 32.8 × 40.7 mm, 32.6 × 41.6 mm, 30.0 × 36.6 mm, 28.0 × 35.0 mm, 25.9 mm, 32.7mm, 24.7 × 30.6 mm, 22.2 × 27.4 mm, 21.4 × 26.0 mm, 21.0 × 26.2 mm, 20.5 × 24.7 mm, 18.5 × 22.6 mm, 15.8 × 18.8 mm, 15.3 × 18.7 mm, 16.7 × 20.6 mm, 16.5 × 20.3 mm, 13.2 × 15.8 mm, 13.0 × 15.7 mm, 12.0 × 14.8 mm, 11.8 × 13.8 mm; 12 ♀: 32.6 × 41.8 mm (photo), 27.5 × 34.2 mm, 27.4 × 35.4 mm, 26.4 × 33.0 mm, 22.4 × 27.7 mm, 20.4 × 25.7 mm, 17.9 × 21.6mm, 17.6 × 21.7 mm, 16.2 × 19.7 mm, 13.4 × 16.4 mm, 13.2 × 16.3 mm; in ethanol; Côte sud de Grande Terre, Anse Vinaigri, Stn 131; Muséum Antilles 1978; 9. VI.1978; as Gecarcinus lateralis ; MNHN-IU-2017-8390 (= MNHN-B24656 ) • 1♂ 28.2 × 36.3 mm; Îles des Saintes , Terre-de-Haut; KARUBENTHOS 3; Stn IGM1 ; 15°52.6’N, 61°34.7’W; 8.X.2024; MNHNARBig-LPRig coll.; MNHN-IU-2024-5132 • 1 ♀ 29.3 × 35.9 mm; Guadeloupe , Marie-Galante; KARUBENTHOS 3, Stn IGM25 , 15°53.3’N, 61°13.3’W; 16.X.2024; MNHN-ARBig-LPRig coll.; MNHN-IU-2024-5551 .

Martinique • 1 ♂ 27.8 × 34.6 mm; dry; M. Bélanger; as Gecarcinus lateralis ; MNHN-IU-2000-10768 (= MNHN-B10768 ) • 1 ♂ 28.8 × 35.5, 1 ♀ 28.0 × 35.0; dry; M. Bélanger; as Gecarcinus lateralis ; MNHN-IU-2000-3755 (= MNHN-B3755 ) • 1 ♂ cl 26.2 ca damaged; dry; as Gecarcinus lateralis ; MNHN-IU-2000-3756 (= MNHN-B3756 ) .

Cayman Islands, Little Cayman • 1♂ 29.0 mm × 37.0 mm, Cayman Expedition, 1938; in bush and plantation; Coll. Oxford University, 1952; 1.17.4-6; det. Gecarcinus ruricola ; NHM .

Bahamas • 1♂ 43.6 × 57.4 mm; dry; as Gecarcinus ruricola ; MNHN- IU-2000-10933 (= MNHN-B10933).

Panama • 1 ♂ 44.7 × 56.7 mm; Naos Island; Panama Survey ; 4.V.1971; C. A. Child, det Gecarcinus ruricola ; USNM 155253 .

Gulf of Mexico, Florida • 2 ♂ 31.0 × 39.9 mm, 32.3 × 40.5 mm, 2 ♀ 38.3 × 47.2 mm, 31.6 × 38.8 mm; Florida Keys ; Loggerhead Key, N. End; 30.VII.1926; Rathbun det. Gecarcinus ruricola ; USNM 71219 . (See Fig. 5A, B ) .

Nicaragua • 2 ♂ 32.4 × 44.2 mm, 31.0 × 40.3 mm, Greytown, Rathbun det. Gecarcinus ruricola ; label by Carson: “looks like to me G. lateralis ”; 25.X.1965; Barnwell det. G. lateralis , 14VIII.1975; USNM 74612. (See Fig. 5C, D ).

French Guiana • 1 specimen 18.0 × 23. mm (damaged); dry; M. Leprieur; as Gecarcinus lateralis ; MNHN-IU-2000-3754 (= MNHNB3754 ) .

Mexico • 1 ♂ 43.0 × 55.0 mm; in ethanol; Playa Isla Blanca , Quintana Roo; 21.VII.2018; as Gecarcinus lateralis ; CNCR 35126 .

TYPE LOCALITY. — Guadeloupe (see N. K. Ng et al. 2019: 99, 100).

DIAGNOSIS

Carapace

Carapace of smaller size than Gecarcinus ruricola , broader than long but proportionally less broad than G. ruricola , relatively flat, with hepatic, subhepatic and branchial regions not markedly inflated; widest part of carapace being in line with antero-lateral angles of mesogastric region. Fronto-orbital distance about half or a little less than half of maximum carapace width in adults. Dorsal surface with shallow grooves: cervical groove ending anteriorly in a pit near orbital angle; median (or urogastric) groove and longitudinal mesogastric groove rising towards frontal margin. Numerous striae along lateral margins of the carapace, used as stridulatory pars stridens. Front short, broad, moderately produced and deflexed, widening very little below, its inferior margin being slightly arcuate. Mesial lobe of infraorbital margin angular, just joining front edge and completely exposed. Antero-lateral margins entire, not markedly rounded, joining exorbital angle, with more or less marked junction; marked by granular row in females.

Cephalic structures

Antennules very small, folded obliquely. Antennae very short, completely exposed. Orbits small, with marked angle at anterolateral margin. Eyestalks relatively short, curved.

Proepistome, epistome and pterygostome

Proepistome covered by subfrontal plate. Epistome developed, with one median crest and a lateral crest on each side, setose. Buccal cavity rhomboid. Subhepatic and pterygostomial region glabrous, with many striae.

Mxp3

Mxp3 rather small, not reaching epistome, leaving between them a narrow rhomboid gap, in longitudinal position. Ischium and merus subequal, with their articulation only slightly oblique; ischium barely smaller than merus, without longitudinal groove (only a small trace); merus only slightly directed obliquely, not narrowing anteriorly; anterior margin with slight but distinct emargination, sometimes only concave and with barely marked notch; meri of both sides not joining medially; palp inserted below merus: palp with first article fused to merus internal surface and with mobile distal article barely exposed. Exopod of mxp3 as narrow plate, completely concealed by fringe of thick setae, apex not reaching ischium-merus articulation; without flagellum.

Chelipeds

Male chelipeds massive but not extraordinarily enlarged, very unequal especially in old males, widely gaping; heterochely variable, usually slightly marked; occlusal margins of fingers with small, spaced teeth on both sides; in the rare cases of greatly uneven chelipeds (heterochely), a more pronounced gap and pronounced heterodonty. Merus and carpus of adults without row of granules, entirely smooth or may be with two spiniform granules; young adults with two rows of teeth on merus and spiniform granules on inner margin of carpus. Inner surface of palm of chelae used as stridulatory plectrum by rubbing on pterygostomial striae (pars stridens).

Female chelipeds subequal or nearly so, moderately gaping, therefore sexual dimorphism moderate.

Ambulatory legs

P3 moderately spiny. Propodus with unequally developed lateral carinae bearing four rows of weakly developed spines. Dactylus with four rows of small equal spines.

Sterno-pleonal cavity and pleon

Sterno-pleonal cavity completely glabrous, short, ending far from sternal suture 2/3, with marked ridge around telson. Male pleon moderately long, bell-shaped; with all somites free plus telson; lateral margins with fringe of setae; somite 6 with convex lateral margins, forming lateral shoulder; telson campanulate, narrower than somite 6, with lateral margins slightly marked, tip rounded, relatively narrow.

Female pleon subcircular; telson forming isosceles triangle, as wide as or slightly narrower than posterior margin of somite 6, lateral margins straight, smooth.

Thoracic sternum, locking pleonal structures and setal tufts Thoracic sternum wide, narrowing at level of somite 5, thus restricted at level of P1; sternite 1 as small triangular tooth, not separated by suture from sternite 2, not recessed; sternite 2 semi-ovate, with strongly convex margins; suture 2/3 present, practically straight or barely concave and only forming an obtuse angle; suture 3/4 absent, without lateral trace; sternites 3 +4 completely fused, with concave, obliquely directed margins; sutures 4/5 to 7/8 interrupted; sternites 5-7 similarly shaped, sutures well defined; suture 7/8 rather short; sternite 8 not developed medially, totally hidden when pleon is folded; posterior emargination reaching sternite 7; at level of suture 7/8 only some traces of bridges; deep median line only along sternite 7.

Locking pleonal structure as prominence covered by setae, rather close to suture 4/5; corresponding pleonal sockets not delineated, so pleonal locking no longer functional ( Guinot & Bouchard 1998: 660, 685; Köhnk et al. 2017: 2212).

Setal tufts of more or less dense hydrophilic setae located along first pleonal somites, margins of pleon and at its junction with carapace.

Male gonopore and penis

Male gonopore and penis at level of suture 7/8 emerging rather far from P5 coxo-sternal condyle.

G1 and G2

G1 slightly tapering at its extremity, apex short, with unequal setae at its end; laterally, a very long, narrow, horny, unfolded and curved tube, open over a long length and exceeding G1 tip; several horny setae at its base.

G2 very small, without flagellum.

Vulvae

Protruding, oriented nearly horizontally, normally occluded by rigid calcified immobile operculum.

COLOUR

Based on Gecarcinus lateralis from Bermuda described by Verrill (1908: 308), Rathbun (1918: 356) wrote: “Commonly the carapace is mostly of a deep reddish brown or plum color; often this color is replaced posteriorly by a wide transverse band of lighter color spotted with yellow; this band extends forward, along each side, becoming narrower and darker, disappearing near the eye-sockets; a pair of small white spots close behind the eye-sockets and another pair in the cardiac region; legs light grayish brown; chelipeds darker and more red; last joint bright orange, underside white.” See also Chace & Hobbs (1969: 198, figs 5A-C, 6A-C, 7, 8, as G. lateralis ); Parasram et al. (2021: fig. 8, as G. lateralis ) ( Fig. 19 ).

According to Perger & Wall (2014: 105, table 2), the colour of the Pacific Gecarcinus lateralis they examined showed little variation (see their figs 5A, 7E-F, 8G, H) and did not approach the range of variability found in G. lateralis from the Atlantic coast of Central America, characterised by morphs with transitional forms (see their figs 5B, C, 7A-D, 8A-F). For a detailed study of the colour variation in G. lateralis from Bimini, Bahamas, and from the Bermudas, see Martinez & Bliss (1989: figs 1-12, pls 1-3, as G. lateralis ).

VERNACULAR NAMES

‘Black land-crab’, ‘common land-crab’ ( Rathbun 1918); ‘black-backed land crab‘ in Saint Martin ( Yokoyama 2013). Also called ‘Tourloulou’ or ‘Touloulou’, like other species of Gecarcinidae , including Gecarcinus ruricola .

REMARKS

The authorship of Gecarcinus lateralis is traditionally attributed to Fréminville (1835) (e.g. H. Milne Edwards 1837 a; Chace & Hobbs 1969; Türkay 1970; Bliss et al. 1978; Hartnoll et al. 2006a, b; Ng & Guinot 2001; Ng et al. 2008; Perger & Wall 2014). Low et al. (2013) stated that Guérin (1832 in Guérin 1829-1837) should have priority. Fréminville (1835) described Ocypoda lateralis from Guadeloupe and its islands (Les Saintes, Marie-Galante, La Désirade), and Martinique in the West Indies, based on specimens he probably collected himself. In the introduction to this paper (1835: 213, footnote), the editor of the volume, namely H. Milne Edwards, indicates about Fréminville’s ‘tourlourou’: “son Ocypoda lateralis est une espèce de Gécarcin bien distincte et dont j’ai donné une figure dans mon Histoire naturelle des Crustacés. M. Guérin l’a également figurée dans son Iconographie du règne animal. ” [“his Ocypoda lateralis is a clearly distinct species of ‘Gecarcin’ and to which I have given a figure in my Histoire naturelle des Crustacés. M. Guérin has also figured it in his Iconographie du règne animal ”]. Guérin (1832, in Guérin 1829-1837: 7) had previously used the name “ Gecarcinus lateralis Fréminville ” and illustrated what is clearly the same species. It is very likely that Guérin used the same material as Fréminville and that he was aware of the future species by Fréminville. According to the official dates, Guérin’s plate has been published before the description by Fréminville in 1835. According to Low et al. (2013), the authorship of G. lateralis must be credited to Guérin (1832). But, as Fréminville is solely responsible for the species name in a way satisfying the criteria of availability (Code, Art. 50.1.1), the authorship of G. lateralis should be credited to Fréminville in Guérin (1832) (see N. K. Ng et al. 2019).

As explained by N. K. Ng et al. (2019: 100), Türkay (1970), based on erroneous indications given by J. Forest, the curator of Crustacea Collection in the MNHN at the time, regarded as the type series of Gecarcinus lateralis material collected by two French naturalists, Beaupertuis and Bélanger, and deposited in this institution. That is why Türkay (1970: 337) selected as lectotype of Gecarcinus (Gecarcinus) lateralis a specimen from Guadeloupe collected by Beaupertuis, MNHN-IU-2000-3758 (= MNHN-B3758). Türkay (1974: 974, 975, fig. 2) then designated as paralectotypes one male and one female from Guadeloupe, MNHN-IU-2000-3757 (= MNHN-B3757), and two males and one female collected by Bélanger from Martinique, MNHN-IU-2000-3755 (= MNHN-B3755), MNHN- IU-2000-3756 (=MNHN-B3756). A colour figure of this lectotype was published by Perger & Wall (2014: fig. 6AC). However, Beaupertuis’ and Bélanger’s specimens were probably not collected during this period (i.e., before 1832), these two naturalists having travelled in the Antilles later on, as shown by the entry dates of their material in the CAA (Beaupertuis: 1839 from Guadeloupe; Bélanger: 1859, 1860, 1864 from Martinique), and cannot constitute the original material seen by Guérin (1832). The specimen from Guadeloupe previously referred to, although unsupported, as the lectotype of this species by Türkay (1970), then by Perger & Wall (2014), registered MNHN-IU-2000-3758 (= MNHN-B3758) and eligible for neotype designation, was selected as the neotype of G. lateralis by N. K. Ng et al. (2019: 99, fig. 2F).

Türkay (1974: 974, fig. 2, as G. lateralis ) found that the mxp3 showed a high degree of variability in the shape of the merus emargination, and this even in the type series where it may be different in each side.

GEOGRAPHICAL DISTRIBUTION

Hartnollius lateralis n. comb. is distributed along the American Atlantic coast, from Florida to Venezuela and Guiana. Records include Texas ( Ray 1967; Britton 1976), and Florida Keys ( Bright & Hogue 1972: 21, as Gecarcinus lateralis ; Hartnoll 1988a: fig. 2.6, as Gecarcinus lateralis ). In the Caribbean Sea, it is present in Honduras, Swan Islands, Nicaragua, Costa Rica, Panama, Colombia, and in the islands Guadeloupe, Martinique, Puerto Rico, Haiti, Jamaica, Cuba, Bahamas; and also in Bermuda. Toledano-Carrasco et al. (2021) assumed that the records from the American Pacific coast by Türkay (1970), Rathbun (1918), Capistrán-Barradas et al. (2003), Perger & Wall (2014) and Toledano-Carrasco (2016) were actually H. quadratus n. comb. Based on species distribution, the Gecarcinus quadratus cited by Rathbun (1910: 591; 1918: 358) from ‘Turbo, Colombia’ correspond likely to H. lateralis n. comb. In Rathbun (1910: 591; 1918: 367), the records ‘ Bahamas to Guiana; Bermudas’ of Gecarcinus lateralis correspond well to H. lateralis n. comb.; however, the record from Ecuador cited according to the mention of G. ruricola by Nobili (1901: 46), later synonymised with G. lateralis , corresponds to Hartnollius nobilii n. comb. (see Perger & Wall 2014).

The Gecarcinus ruricola specimens from mainland America, namely from ‘Florida’ (USNM 71219) ( Fig. 5A, B ) (see Rathbun 1918: 355), mentioned by Chace & Hobbs (1969) and Keith (1985), as well as the two males from Nicaragua, Greytown (USNM 74612) ( Fig. 5C, D ), identified as G. ruricola by Rathbun and mentioned by the two same authors but not confirmed by other sources, are in fact Hartnollius lateralis n. comb; see above under G. ruricola ).

Gecarcinus ruricola is partially sympatric with Hartnollius lateralis n. comb. in many areas of the Caribbean: namely in the western Atlantic islands, in Lesser Antilles (e.g. Martinique, Guadeloupe, Saint Martin, Saint-Barthelemy), in Greater Antillen ( Jamaica, Cuba) and in the Bahamas ( Rathbun 1918; Toledano-Carrasco & Villalobos Hiriart 2018).

BIOLOGY

Several important contrasts between Gecarcinus ruricola and Hartnollius lateralis n. comb. are treated under the first (see above). H. lateralis n. comb. is more common than G. ruricola , often found 6-9 m above high-tide mark but sometimes up to 1000 m from shore, and is largely herbivorous, but also opportunistic carnivore and cannibal ( Wolcott & Wolcott 1984; 1988: fig. 3.3.9; Burggren & McMahon 1988: fig. 3.6).

According to studies on Hartnollius lateralis n. comb. carried out by Bliss et al. (1978: figs 6, 7-11, 13-31, as Gecarcinus lateralis ) at Sabal Point, just north of Boca Raton Inlet, Florida, with environmental conditions supporting a dense population of H. lateralis n. comb., the crabs can be seen outside of their burrows during the daytime, an unusual behaviour for this species that is typically an active burrower. In eastern Florida, H. lateralis n. comb. inhabits wooded areas of dune ridges and back dunes, under logs and leaf litter, and burrows in dry sandy areas; it is primarily nocturnal ( Powers 1977: 139). In Martinique, traps to catch the ‘touloulou’, e.g. ‘ Z’attrap crab’ or ‘ bwèt à krab’, are placed over the holes. Observations on the species in Bermuda by Savazzi (1985: figs 1A, 2A, 3A, B, 4, 5A, B, as Gecarcinus lateralis ; see also Schmalfuss 1978) showed that it excavates permanent tunnels in compacted soil in grass-covered areas or among tree roots and boulders: finely tuberculated terraces on the chelipeds, around the sides of the carapace and on the walking legs, are related to a wedging function (see also Davie et al. 2015a: fig.71.2.30C).

In Hartnollius lateralis n. comb., moulting and mating can take place inside the burrow, thus far inland. Males defend burrows during breeding migrations ( Wolcott 1988: fig. 3.3.10). Ovigerous females must leave their terrestrial burrows and adopt several types of behaviour to reduce the risks (predators, extremes of salinity and wave impact) for both adult females and larvae during migration and spawning, i.e., migrate directly toward the shore (reducing the time to reach the sea, avoiding standing water) to carry their developing egg masses to the surf and release their eggs. Females spawn synchronously; ovigerous females actively release eggs only when they are ripe, preventing premature release ( Wolcott & Wolcott 1982, 1988, as G. lateralis ). Young crabs come up these beaches to live on land. Fertility is very high in land crabs compared to any of soil inhabitants (e.g. berried females of Hartnollius lateralis n. comb. carry between 19 000 and 109 000 eggs each ( Klaassen 1975, as Gecarcinus lateralis ; Green et al. 1997, as G. lateralis ), and this high reproductive potential ensures the prosperity of crabs in terrestrial habitats. See Britton et al. (1982) for biometric and ecological relationships, including habitat preferences, activity pattern and resource allocation.

During the night and when disturbed in their burrows during the day, Hartnollius lateralis n. comb. as well as H. quadratus n. comb. are known to produce sounds ( Klaassen 1973: figs 1-5; 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). However, in the case of Gecarcinus ruricola , which has similar striae in the same region, this type of communication does not seem to have been reported.

Figures

FIG. 5. — Specimens from mainland America identified by Rathbun as Gecarcinus ruricola (Linnaeus, 1758), but being in fact Hartnollius lateralis (Fréminville in Guérin, 1832) n. comb. A, B, ♂ 32.3 × 40.5 mm, Florida, Florida Keys, Loggerhead Key, USNM 71219: A, general dorsal view; B, ventral view; C, D, ♂ 32.4 × 44.2 mm, Nicaragua, Greytown, Rathbun det. Gecarcinus ruricola; labels by Carson and Barnwell indicating G. lateralis, USNM 74612; C, general dorsal view; D, ventral view. Scale bars: 10 mm. Credits: MNHN-Soubzmaigne.

FIG. 9. — Hartnollius n. gen., general views:A, H. lateralis (Fréminville in Guérin,1832) n. comb.,♂ 42.0 × 56.0 mm,Guadeloupe, MNHN-IU-2017-8390 (= MNHN- B24656); B, H. quadratus (Saussure, 1853) n. comb., ♂ 50.0 × 64.0 mm, Mexico, MNHN-IU-2017-8391 (= MNHN-B20900). Scale bars: 20 mm. Credits: MNHN- Soubzmaigne.

FIG. 10. — A-C, frontal views,D-F, chelipeds:A, Gecarcinus ruricola (Linnaeus,1758),neotype,♂ 55.0 × 76.0 mm,Cuba,MNHN-IU-2017-8392 (= MNHN-B13155); B, Hartnollius lateralis (Fréminville in Guérin, 1832) n. comb., ♂ 43.0 × 55.0 mm, Mexico, CNCR 35126; C, Hartnollius quadratus (Saussure, 1853) n. comb., ♀ 36.0 × 46.0 mm, Mexico, CNCR 24607; D, Gecarcinus ruricola (Linnaeus, 1758), neotype, ♂ 55.0 × 76.0 mm, Cuba, MNHN-IU-2017-8392 (= MNHN-B13155): see granules on margins of merus and carpus of chelipeds; E, Hartnollius lateralis n. comb., ♂ 43.0 × 55.0 mm, Mexico, CNCR 35126: see smooth margins of chelipeds; F, Hartnollius quadratus (Saussure, 1853) n. comb., ♂ 43.0 × 55.0 mm, Mexico, CNCR 34630: see smooth margins of chelipeds. Scale bars: 10 mm. Credits: A, D, MNHN-Soubzmaigne; B, C, E, F, CNCR-Toledano-Carrasco.

FIG. 11. — Mxp3, internal view, and palp: A, Gecarcinus ruricola (Linnaeus, 1758), Jamaica, MZUSP 18501 (ex USU-279); B, Hartnollius lateralis (Fréminville in Guérin, 1832) n. comb., Costa Rica, MZUSP 18509 (ex USU-281); C, H. quadratus (Saussure, 1853) n. comb., Mexico, MZUSP 18859 (ex AHF) (see Tavares 1989: fig. 14). Courtesy Marcos Tavares.

FIG. 12. — Hartnollius lateralis (Fréminville in Guérin, 1832) n. comb., ♂ 42.0 × 56.0 mm, Guadeloupe, MNHN-IU-2017-8390 (= MNHN-B24656): A, frontal view; B, front, orbit,and mesial lobe of infraorbital margin;C, front,proepistome (hidden), antenna (exposed) and mesial lobe of infraorbital margin; D, thoracic sternum and male pleon; E, F, external and internal views of chelipeds. Scale bars: A, D, E, F, 10 mm; B, C, 5 mm. Credits: MNHN-Soubzmaigne.

FIG. 13. — Harrtnollius n. gen.: gonopods and vulvae:A, B, Hartnollius lateralis (Fréminville in Guérin, 1832) n. comb., Guadeloupe, MNHN-IU-2017-8390 (= MNHN-B24656): A, ♂ 40.5 × 55.7 mm: G1, G2, caudal view; B, ♀ 32.6 × 41.8 mm:vulvae;C, H.quadratus (Saussure,1853) n.comb.,♂ 50.0 × 64.0 mm, Mexico, MNHN-IU-2017-8391 (= MNHN-B20900):G1, G2, caudal view. Scale bars: A, C, 2 mm; B, 1 mm. Credits: MNHN-Soubzmaigne.

FIG. 16. — Bayesian inference phylogenetic tree of Gecarcinidae based on the concatenation of mitochondrial COI and 16S rRNA gene fragments.Numbers at nodes are support values for BI (posterior probability) and ML (Ultrafast bootstrap). The clade of crabs with less terrestrial habits (Cardisoma Latreille, 1828, Discoplax A.Milne-Edwards,1867,and Tuerkayana Guinot,N. K. Ng & Rodríguez Moreno, 2018) are highlighted in purple,whereas the clade with markedly terrestrial habits (Gecarcinus Leach, 1814, Hartnollius n. gen. and Johngarthia Türkay, 1970) are highlighted in red. Ocypode rotundata Miers, 1882 was included as outgroup.

FIG. 19. — Hartnollius lateralis (Fréminville in Guérin,1832) n. comb., living and in the field:A, Guadeloupe,Marie-Galante, KARUBENTHOS 3, Stn IGM25,MNHN- IU-2024-5551; B, C, Guadeloupe, July 2015, on sand; D, E, Martinique, Anse à Prunes, forest about 65 m far from the shore, altitude about 2 m; D, crab bearing a branch; E, crab on a tree. Credits: A, L. Corbari-MNHN-ARBig-LPRig; B, C, J. Poupin; D, E, F. Lavail (planetedoc.com).