Tuerkayana rotundum ( Quoy & Gaimard, 1824 )

Ng and Hsi-Te Shih, Peter K. L., 2023, Tuerkayana latens, a New Species of Land Crab from French Polynesia, with a Discussion on the Phylogeny of the Genus (Crustacea: Decapoda: Brachyura: Gecarcinidae), Zoological Studies 62 (10), pp. 1-21 : 2-7

Tuerkayana rotundum ( Quoy & Gaimard, 1824)

( Figs. 1 , 2 , 5 , 6 , 7A, B , 8A–E , 9A–C , 10A–C, E–G , 11A–C, E–G, I–K )

Thelphusa rotunda Quoy & Gaimard, 1824: 527 , pl. 77 fig. 1 [type locality: as “Océanie” = Guam]; NK Ng et al. 2019: 101, fig. 3B [lectotype designation].

Cardisoma frontalis H. Milne-Edwards, 1853: 204 ; De Man 1902: 548, pl. 20 fig. 14; Tweedie 1950: 138, fig. 4h.

Discoplax pagenstecheri Kossmann, 1878: 255 .

Cardisoma rotundum – Türkay 1974a: 234, figs. 1, 14 (part); Sakai 1976: 679, pl. 232; Türkay and K. Sakai 1976: 14, figs. 3, 5, pl. 2(1–2); Takeda 1982: 225; Miyake 1983: 188, pl. 63(3); Hirata et al. 1988: 5, 1 unnumbered fig.; Ho et al. 1992: 61, fig. 6; Poupin 1994: fig. 50; PKL Ng 1998: 1151, 1 unnumbered fig.; Liu 1999: 85, figs. 30–31.

Discoplax rotundum – Lee 2001: 140, 2 unnumbered figs.; PKL Ng et al. 2001: 49; Davie 2002: 185; Lin et al. 2011: 37, 2 unnumbered figs.; PKL Ng et al. 2017: 97.

Discoplax rotunda – Innocenti and Vannini 2007: 635, fig. 1; PKL Ng et al. 2008: 214; Poupin and Juncker 2008: 35, fig. 5d; Poupin 2010: 42 (part); Poupin and Juncker 2010: 56 (part), 1 unnumbered fig. on p. 57; Orchard 2012: 149, 6 unnumbered figs.; Li and Chiu 2013: 65, 3 unnumbered figs.; Shih 2013 b: 28, fig. 9; PKL Ng and Shih 2014: 111; Toyota et al. 2014: 180, 7 unnumbered figs.; PKL Ng and Shih 2015: 382; Li and Chiu 2019a: 98, 3 unnumbered figs.; Li and Chiu 2019b: 2 unnumbered figs. on p. 52.

Tuerkayana rotundum – Guinot et al. 2018: 551, fig. 4G; Sasaki 2019: 12702; Toyota et al. 2019: 188, 4 unnumbered figs.

Diagnosis: Frontal, epigastric, epibranchial and anterior part of mesobranchial regions covered with numerous small granules and striae, those on anterior part more flattened; mesogastric, metagastric regions almost smooth; posterior part of meso-, metabranchial regions with prominent oblique striae and granules; epigastric regions prominent, margin relatively sharp; postorbital cristae strong, separated from epigastric by shallow concavity; external orbital tooth broadly triangular, margin confluent with anterolateral margin, separated by short narrow fissure or small cleft ( Figs. 2 , 5 , 6 , 7B ). Merus of third maxilliped subovate, longer than broad ( Fig. 7A ). Surfaces of adult chelae with low granules on margins, punctate to rugose ( Fig. 9A–C ). Ambulatory legs short; ratios of maximum length to maximum width of third and fourth ambulatory meri 2.5–2.6, 2.5–2.6, respectively; surfaces covered with striae, appears rugose; dorsal margin of merus rugose, uneven; lateral margins of propodus, dactylus lined with strong, stiff spines or setae ( Figs. 2 , 10A–C, E–G ). Male pleon relatively broad; somite 6 wider than long, lateral margins gently to strongly convex ( Fig. 8A–F ). Adult G1 almost straight, when viewed from ventral perspective; distal part curved at angle of about 45° from vertical; distal part of outer margin forming gentle shelf–like structure; distal part gently curves towards corneous tip, basal part tapers gradually to truncate tip in dorsomesial view, outer margin appearing gently concave in ventral view, forming relatively narrow triangular flange ( Fig. 11A–C, E–G, I–K ). Eastern Indian Ocean to Niue.

Material examined: Guam – lectotype male (63.0 × 50.0 mm) (MNHN-IU-2000-3745 = MNHN-B3745) [photographs examined], Guam, Oceania, M. Guérin; 1 male (ZRC 2000.568), coll. P.K.L. Ng, October 1996; 1 female (ZRC 2000.567), Hawaiian Rock Quarry, central Guam, coll. 20 April 2000; 2 females (ZRC 2001.703), Merizo, Guam, coll. P.K.L. Ng, 1 August 2001; 1 male (50.2 × 38.6 mm), 1 female (48.2 × 36.9 mm, with hatched zoeae) (ZRC 2000.566), Pago Bay, outside of marine laboratory, University of Guam, coll. P.K.L. Ng and C.-H. Wang, 15-18 April 2000. Taiwan – 1 male (ZRC 1998.471), Pingtung County, coll. H.-C. Liu et al., 13 May 1998; 1 male (53.3 × 41.0 mm) (ZRC 1998.474), 1 male, 1 female (ZRC 1998.432), Pingtung County, Taiwan, coll. H.- C. Liu et al., 22 May 1998; 1 female (ZRC 1998.476), Pingtung County, Taiwan, coll. H.-C. Liu et al., 18 Sep. 1997; 1 male (37.5 × 29.3 mm) (NCHUZOOL 15886), Siangjiaowan, Pingtung County, coll. 2 September 2000; 1 female (39.4 × 31.5 mm) (NCHUZOOL 15887), Dingtanzih, Kenting, Pingtung County, coll. 17 March 2018; 1 ovig. female (33.8 × 25.0 mm) (NCHUZOOL 15888), Dingtanzih, Kenting, Pingtung County, 27 August 2018. Japan – 1 male (SMF 6382), south of Daito-Jima, Riu-Kiu (= Ryukyu Islands), no other data. Philippines – 1 female (ZRC 2001.312), Tawala Cave, Panglao Island, Bohol, Philippines, coll. P.K.L. Ng et al., 17 December 2000; 1 male (47.8 × 37.8 mm) (ZRC 2008.506), Virata Cave, Panglao Island, Bohol, coll. Manong et al., 26 November 2001; 2 males (ZRC 2008.1005), Hinagdanan Cave, northern part of Panglao Island, Bohol, coll. local collectors, June 2002; 1 male (ZRC 2001.2311), Baloc-Baloc Cave, near Virata Cave, Panglao Island, Bohol, coll. Manong et al., 30 November 2001; 1 male (ZRC 2014.463), Panglao Island Nature Resort, Hinagdanan Cave, coll. P.K.L. Ng, 3 March 2004; 1 male (ZRC 2021.865), station M59, Cambagat Cave, Panglao, 9°37.5'N 123°48.1'E, coll. PANGLAO 2004 Expedition, 5 July 2004; 3 males, 3 females (ZRC 2012.437), outside cave at Panglao Island Nature Resort, Panglao Island, Bohol, coll. P.K.L. Ng and P.Y.C. Ng, December 2010; 1 female (ZRC 2001.2312), Balicasag Island, Panglao Island, Bohol, A. Porpetcho and R. Diaz, 30 November 2001; 1 male (SMF 19745), east Mactan, northwest coast of Hilutangan Channel, Cebu, 10°17'N 124°00'E, coll. A. Schreiber. Indonesia – 1 male (33.9 × 26.9 mm) (SMF), station Ip-1, Ambon, coll. Rumphius Expedition, K. Moosa, 17 January 1973; 1 ovigerous female (ZRC 2010.423), Kri Island, West Papua, coll. H.H. Tan, December 2010. Papua New Guinea – 1 female (SMF 24451), Kavieng, New Ireland, coll. 19 July 1998. Admiralty Islands – 2 males (36.6 × 28.8 mm, 35.9 × 28.3 mm), 1 female (40.4 × 30.9 mm) (SMF 5854), Nissan Atoll, Pinipal, Hanseatischen Südsee-Expedition, coll. E. Wolff, 8 May 1909; 1 female (53.1 × 41.0 mm) (SMF 5855), Pak, Hanseatischen Südsee-Expedition, coll. E. Wolff, 10 September 1909. New Caledonia – 1 male (61.4 × 78.0 mm) (MNHN–B 24813), Easo Cave, 17 m depth, Lifou Island, Loyalty Islands, coll. B. Richer de Forges, 20 August 1993; 1 male (28.0 × 26.3 mm) (MNHN–B 24809), on the ground, Lifou Island, Loyalty Islands, coll. B. Richer de Forges, 18 April 1993; 2 females (38.0 × 48.0 mm, 39.0 × 49.0 mm) (MNHN-B 24814), sea level, Maré Island, Loyalty Islands, coll. B. Richer de Forges, 16 July 1993; 1 juvenile (3.0 × 3.5 mm) (MNHN–B 26947), cave, station 88–066, Ouvea Atoll, Loyalty Islands, coll. T.M. Iliffe and S. Sarbu, 22 June 1988; 9 juveniles (MNHN-B 26948), Loyalty Islands, Luecilla Cave, station 88–058, Lifou Island, coll. T.M. Iliffe and S. Sarbu, 17 June 1988; 3 males (47.2 × 37.6, 47.2 × 37.7, 52.9 × 41.9 mm) (MNHN-IU-2014-10106), Lifou I. (Hnyekej), coll. J. Poupin and M. Juncker, 2005; 1 male (36.0 × 44.0 mm) (MNHN-B 17134), no other data. Solomon Islands – 1 young female, 6 juveniles (12.7 × 16.5 mm) (MNHN-B 26943), Malaita, coll. T.M. Iliffe and S. Sarbu, 27 August 1988. Vanuatu – 2 males (37.6 × 29.0 mm, 37.0 × 28.4 mm) (ZRC 2012.103), Espiritu Santo, entrance of Loren Cave, coll. G. Boxshall, 13 September 2006. Tuvalu Islands – 1 male (42.9 × 34.3 mm) (UF 6316), among breadfruit leaves, area with coconuts, strand vegetation, 2 m asl, Vaiaku, Fongafale, Tuvalu, Funafuti Atoll, coll. L. Kirkendale, 23 June 2004. Wallis & Futuna Islands – 1 female (38.3 × 29.5 mm) (MNHN-IU-2013-13174), coll. J. Poupin, 2007. Niue – 1 male (51.7 × 41.6 mm) (UF 2192), supratidal to well inland, Hakupu area, coll. B. Holthuis and G. Paulay, 9 April 1991. Australian Seas – 1 female (holotype of Discoplax pagenstecheri Kossmann, 1878 ) (55.1 × 44.1 mm) (SMF 6872) (ex Mus. Heidelberg Cr190, Mus. Godeffroy). Cocos-Keeling Islands ( Australia) – 1 male (46.5 × 57.4 mm) (ZRC 1965.12.1.7), coll. C.A. Gibson–Hill, 1941; 1 male, 1 female (ZRC 1965.12.1.8–9), coll. M.W.F. Tweedie, 1941; 1 male (57.6 × 44.5 mm) (ZRC 2013.1074), Horsburgh Island, coll. P.K.L. Ng et al., 23 March 2011; 6 males, 1 female (ZRC 2013.1075), Horsburgh Island, coll. P.K.L. Ng et al., 23 March 2011; 1 male (ZRC 2013.1084), station CK24, west southwest of Rumah Baru (boat launch point), West Island, coll. P.K.L. Ng, 24 March 2011; 3 males (ZRC 2019.744), within 500 m of landing point on island, North Keeling Island, coll. P.K.L. Ng, 8 February 2012; 1 female (ZRC 2019.741), within 500 m of landing point on island, North Keeling Island, coll. P.K.L. Ng, 8 February 2012; 1 female (ZRC 2019.743), station CK 2-14, National Park Camp, central west side of lagoon, North Keeling Island, coll. P.K.L. Ng, 8 February 2012; 1 male, 1 female (ZRC 2021.866) National Park Camp, central west side of lagoon, North Keeling Island, coll. P.K.L. Ng, 8 February 2012. Mauritius – 1 male (no other data), Mauritius Institute.

Colour: The adult coloration of T. rotundum is surprisingly variable. Most specimens tend to have a dark brown carapace, the ambulatory legs are usually dark brown with the joints and dactylus orange, and the chelipeds are reddish-brown to purplish with palecoloured fingers ( Fig. 1A, B, E, F ). Some specimens, however, are much lighter in colour with yellow to orange chelipeds and ambulatory legs ( Fig. 1B, C ).

Distribution: East Africa ( Kenya), Aldabra, Seychelles, Mauritius, Cocos-Keeling Islands, Christmas Island, Japan (Ryukyus), Taiwan, Philippines, Indonesia ( Ambon), Papua New Guinea, Guam, Ujae Atoll, Solomon Islands, Vanuatu, New Caledonia, Tuvalu Islands, Wallis & Futuna, Tokelau, Niue, Cook Islands.

Remarks: This well-known species has a wide distribution in the western Indian Ocean to western Pacific ( Fig. 13 ) and the taxonomy has been treated at length by Türkay (1974a: 234). The type of the species is still extant, with Guinot et al. (2018: 551) listing a syntype male measuring 63.0 × 50.0 mm in the MNHN as obtained from “Oceania”. Quoy and Gaimard (1824: 527) had stated in the original paper that the material was from Guam. NK Ng et al. (2019: 101) designated this dried male specimen in MNHN as the lectotype of the species (MNHN-IU-2000-3745). Our material from Guam agrees very well with their description and figure ( Guinot et al. 2018: fig. 4G, NK Ng et al. 2019: 101, fig. 3B). Henri Milne Edwards (1853) described Cardisoma frontalis from an unknown locality and his description is too brief to be helpful. Most authors have treated C. frontalis as a junior synonym of C. rotundum (see Türkay 1974a b; PKL Ng et al. 2008; Guinot et al. 2018; NK Ng et al. 2019). Türkay (1974b) discussed the issue with the types of these two species, selecting the syntype of Thelphusa rotunda as the holotype, but incorrectly selecting this specimen also as the holotype of Cardisoma frontalis H. Milne Edwards, 1853 . As discussed by NK Ng et al. (2019), the type of C. frontalis is lost and there is no evidence that the specimen(s) of Quoy and Gaimard (1824) and H. Milne Edwards (1853) are the same. They noted that as the synonymy of this species was well accepted and there was no problem with their taxonomy, there was no immediate need to select a neotype for Cardisoma frontalis . With the recognition of a new species from French Polynesia, there is now a problem as it is possible H. Milne Edwards’ (1853) original specimen(s) originated from there. Henri Milne Edwards’ (1853: 204) account for the species is relatively brief and not informative: “Carapace assez semblable à celle du C. carnifex par sa forme Générale et ses crêtes marginales latéro-antérieures, mais s’en distinguant, ainsi que de celle des autres espèces dont il vient d’être question, par la saillie considérable des lobes prégastriques et la profondeur du sillon mésogastrique. Basicérite étroit. Bras du mâle gros et presque de même grandeur des deux côtés; mains renflées; pinces courtes. Pattes ne portant que des poils très courts; le propodite garni en dessus d’une double rangée de petites épines. Patrie inconnue.” [Carapace quite similar to that of C. carnifex in its general shape and its anterolateral ridges, but differing from it, as well as from that of the other species just mentioned, by the considerable projection of the pregastric lobes and the depth of the mesogastric groove. Narrow baserite. Male cheliped large and nearly equal on both sides; swollen palm; short fingers. Legs with only very short hairs; dorsal margin of propodus with a double row of small spines. Unknown provenance.]. It is possible to keep the name Cardisoma frontalis H. Milne Edwards, 1853 by selecting the holotype of the new species from French Polynesia as its neotype. We have, however, decided otherwise because Cardisoma frontalis has long been confused with it and is now generally regarded as the junior synonym of Tuerkayana rotundum . In our opinion, to establish a new name would be less confusing.

Kossmann (1878) described Discoplax pagenstecheri from a female specimen from Australian seas ( Figs. 2F , 5F ); as treated by Türkay (1974a), it is clearly identical to T. rotundum .

Innocenti and Vannini (2007) reported a male specimen of T. rotundum from Mombasa, Kenya. The late Michael Türkay passed the first author photographs ( Fig. 2G, H ) of a specimen he had seen in the Mauritius Institute in the 1970s but has never been published. The adult male specimen (no measurements indicated) is clearly T. rotundum as defined here. Unfortunately, we were unable to obtain this specimen for study, but the photograph leaves no doubt as to its identity. The only record from Christmas Island in the Indian Ocean is a photograph of a specimen observed at the Blowholes on the island ( Fig. 1F ) ( Orchard 2012: 149). It is surprising that it is not common on the island; it is relatively abundant on the nearby Cocos-Keeling Islands ( Tweedie 1950; present data). Rathbun (1906: 838) listed two specimens of “ Cardisoma rotunda ” from Oahu in Hawai’i but there have not been any records since. Castro (2011: 113) discussed this matter at length and concluded that the original specimens had been mislabelled.

Figures

Fig. 1. Colours in life of Tuerkayana rotundum (Quoy & Gaimard, 1824). A, male (47.8 × 37.8 mm) (ZRC 2008.506), Panglao Philippines; B, male (37.6 × 29.0 mm) (ZRC 2012.103), Vanuatu; C, male (37.0 × 28.4 mm) (ZRC 2012.103), Vanuatu; D, male, New Caledonia (specimen not collected); E, male (57.6 × 44.5 mm) (ZRC 2013.1074), North Keeling Island, Cocos-Keeling Islands; F, male, Blowholes, Christmas Island (specimen not collected).

Fig. 2. Overall views of Tuerkayana rotundum (Quoy & Gaimard, 1824). A, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, male (53.3 × 41.0 mm) (ZRC 1998.474), Taiwan; C, male (47.8 × 37.8 mm) (ZRC 2008.506), Philippines; D, female (38.3 × 29.5 mm) (MNHN-IU-2013-13174), Wallis & Futuna Islands; E, male (57.6 × 44.5 mm) (ZRC 2013.1074), Cocos-Keeling Islands; F, female (holotype of Discoplax pagenstecheri Kossmann, 1878) (55.1 × 44.1 mm) (SMF 6872), Australian Seas; G, H, male (no measurements) (Mauritius Institute), Mauritius.

Fig. 5. Dorsal views of carapaces of Tuerkayana rotundum. A, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, male (53.3 × 41.0 mm) (ZRC 1998.474), Taiwan; C, male (47.8 × 37.8 mm) (ZRC 2008.506), Philippines; D, female (38.3 × 29.5 mm) (MNHN-IU-2013-13174), Wallis & Futuna Islands; E, male (57.6 × 44.5 mm) (ZRC 2013.1074), Cocos-Keeling Islands; F, female (holotype of Discoplax pagenstecheri Kossmann, 1878) (55.1 × 44.1 mm) (SMF 6872), Australian Seas.

Fig. 6. Frontal views of carapaces of Tuerkayana rotundum (Quoy & Gaimard, 1824).A, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, male (53.3 × 41.0 mm) (ZRC 1998.474), Taiwan; C, male (47.8 × 37.8 mm) (ZRC 2008.506), Philippines; D, female (38.3 × 29.5 mm) (MNHN-IU-2013-13174), Wallis & Futuna Islands; E, male (57.6 × 44.5 mm) (ZRC 2013.1074), Cocos-Keeling Islands; F, female (holotype of Discoplax pagenstecheri Kossmann, 1878) (55.1 × 44.1 mm) (SMF 6872), Australian Seas.

Fig. 7. Third maxillipeds and carapaces of Tuerkayana species. A, T. rotundum, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, T. rotundum, male (47.8 × 37.8 mm) (ZRC 2008.506), Philippines; C, D, T. latens n. sp., holotype male (52.8 × 42.7 mm) (MNHN-IU-2011-5594), French Polynesia. A, left third maxilliped; C, right third maxilliped; B, D, lateral views of carapaces.

Fig. 8. Thoracic sternums, male pleons and chelae of Tuerkayana species. A, T. rotundum, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, T. rotundum, male (53.3 × 41.0 mm) (ZRC 1998.474), Taiwan; C, T. rotundum, male (57.6 × 44.5 mm) (ZRC 2013.1074), Cocos-Keeling Islands; D, T. rotundum, male (42.9 × 34.3 mm) (UF 6316), Tuvalu; E, T. rotundum n. sp., male (51.7 × 41.6 mm) (UF 2192), Niue; F, T. latens n. sp., holotype male (52.8 × 42.7 mm) (MNHN-IU-2011-5594), French Polynesia.

Fig. 9. Outer views of chelae of Tuerkayana species. A, T. rotundum, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, T. rotundum, male (53.3 × 41.0 mm) (ZRC 1998.474), Taiwan; C, T. rotundum, male (57.6 × 44.5 mm) (ZRC 2013.1074), Cocos-Keeling Islands; D, T. latens n. sp., holotype male (52.8 × 42.7 mm) (MNHN-IU-2011-5594), French Polynesia. A–C, right chelae; D, left chela.

Fig. 10. Third and fourth ambulatory legs of Tuerkayana species. A, E, T. rotundum, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, F, T. rotundum, male (53.3 × 41.0 mm) (ZRC 1998.474), Taiwan; C, G, T. rotundum, male (57.6 × 44.5 mm) (ZRC 2013.1074), Cocos-Keeling Islands; D, H, T. latens n. sp., holotype male (52.8 × 42.7 mm) (MNHN-IU-2011-5594), French Polynesia. A–D, right third ambulatory legs; E–H, right fourth ambulatory legs.

Fig. 11. Left G1s (denuded) of Tuerkayana species. A, E, I, T. rotundum, male (50.2 × 38.6 mm) (ZRC 2000.566), Guam; B, F, J, T. rotundum, male (53.3 × 41.0 mm) (ZRC 1998.474), Taiwan; C, G, K, T. rotundum, male (57.6 × 44.5 mm) (ZRC 2013.1074), Cocos-Keeling Islands; D, H, L, T. latens n. sp., holotype male (52.8 × 42.7 mm) (MNHN-IU-2011-5594), French Polynesia. A–D, ventral views; E–H, dorsal views; I–L, dorsomesial views. Scales: A–D = 5.0 mm; E–L = 2.0 mm.

Fig. 13. Collection sites for Tuerkayana rotundum (Quoy & Gaimard, 1824) (blue squares) and T. latens n. sp. (red squares) used in this study (Table 1). Empty blue and red squares mean the additional records of the two species from other references (e.g., Türkay 1974a; Innocenti and Vannini 2007; Ng and Shih 2014). Different lines indicate the updated ranges of the two species.