Chelarctus cultrifer ( Ortmann, 1897 )

Yang, Chien-Hui & Chan, Tin-Yam, 2012, On The Taxonomy Of The Slipper Lobster Chelarctus Cultrifer (Ortmann, 1897) (Crustacea: Decapoda: Scyllaridae), With Description Of A New Species, Raffles Bulletin of Zoology 60 (2), pp. 449-460 : 450-454

Chelarctus cultrifer ( Ortmann, 1897)

( Figs. 1 , 2 , 4A )

Arctus sordidus – Bate, 1888: 66, pl. 9, Fig. 3 [not Stimpson, 1860]

Arctus haanii – Ortmann, 1891: 42 (in part) [not Scyllarus Haani Berthold, 1845 ]

Arctus cultrifer Ortmann, 1897: 272 (in part) (lectotype locality: Kai Islands, Indonesia)

Scyllarus cultrifer meridionalis Hothuis, 1960: 150 (type locality: Philippines)

Scyllarus cultrifer – Chan, 1997: 413

Chelarctus cultrifer – Holthuis, 2002: 572 (in part), Figs. 26C, 27

[Not] Arctus cultrifer – Ortmann, 1897: 272 (in part); Yokoya, 1933: 46 [= Chelarctus virgosus , new species]

[Not] Scyllarus cultrifer – Balss, 1914: 80; Parisi, 1917: 9; Utinomi, 1956: 62, pl. 31, Fig. 5 ; Kubo, 1960: 98, pl. 49, Fig. 5 ; 1965: 627, Fig. 1023; Miyake, 1961: 9; 1972: 67, unnumbered fig.; 1975: 106, unnumbered fig.; 1982: 84, pl. 29, Fig. 1 ; Harada, 1962: 114, Figs 3–5 , pl. 8, pl. 12, Fig. 13, pl. 13, Fig. 17; 1965: 36, Fig. 1a, b ; Ikematsu, 1963: 10; Nishimura & Suzuki, 1971: 89, pl. 30, Fig. 4 ; Matsuzawa, 1977: pl. 76, Fig. 1 ; Shirai, 1980: 411, unnumbered fig; Takeda, 1982: 43, Fig. 129; Baba, 1986: 163, Fig. 114; Hayashi, 1995: 345, pl. 92, Fig. 4 ; Masuda et al., 1996: 104, unnumbered fig; Chan & Yu, 1993: 217, unnumbered fig; Debelius, 1999: 225, unnumbered fig; Minemizu et al., 2000: 123, unnumbered figs; Kato & Okuno, 2001: 63, unnumbered fig. [= Chelarctus virgosus , new species]

[Not] Scyllarus cultrifer – Holthuis, 1946: 93, pl. 8, Figs. c, e [= Galearctus timidus ( Holthuis, 1960) ]

[Not] Scyllarus cultrifer – Barnard, 1950: 557, Fig. 104a [? = Galeractus timidus ( Holthuis, 1960) ]

[Not] Scyllarus cultrifer – Hwang & Yu, 1983: 264, Fig. 5 [= Petrarctus rugosus (H. Milne Edwards, 1837) ]

[? Not] Scyllarus cultrifer – Wang et al., 1998: 446 [= Chelarctus virgosus , new species]

[Not] Chelarctus cultrifer – Holthuis, 2002: 572 (in part), Fig. 26A, B; Humann & DeLoach, 2010: 153, unnumbered fig. [= Chelarctus virgosus , new species]

[? Not] Chelarctus cultrifer – Zhang & Liu, 2006: 20, Fig. 1-4, 1-5, 1 -6, 4-6 [= Chelarctus virgosus , new species]

Material examined. — Philippines, ALBATROSS, station D 5398, Gigantangan Island , 11°35'12"N, 124°13'48"E, 209 m, 15 Mar.1909, female 22.0 mm cl, holotype of Chelarctus cultrifer meridionalis ( USNM 104525 ) . – MUSORSTOM 1, station 27, 14°00.5'N, 120°15.7"E, 188–192 m, trawl, 22 Mar.1976, 1 ovigerous female 26.0 mm cl (MNHN-IU-2011-5102, ex. MNHN-Pa 1057); station 35, 14°08.0'N, 120°16.5'E, 186–187 m, trawl, 23 Mar.1976, 1 male 22.0 mm cl (MNHN-IU-2011-5103, ex. MNHN-Pa 1053); station 61, 13°59.7'N, 120°16.8'E, 184–202 m, trawl, 27 Mar.1976, 1 female 22.0 mm cl (MNHN-IU-2011-5099, ex. MNHN-Pa 1055); station 72, 14°13.1'N, 120°28.8'E, 122–127 m, trawl, 28 Mar.1976, 1 juvenile 9.0 mm cl (MNHN-IU-2011-5101, ex. MNHN-Pa 1048). –MUSORSTOM 2, station 51, 14°00.4'N, 120°17.6'E, 170–187 m, trawl, 27 Mar.1976, 1 ovigerous female 26.0 mm cl (MNHN- IU-2011-5100, ex. MNHN-Pa 1052). –MUSORSTOM 3, station DR130, 11°37'N, 121°43'E, 178–195 m, 5 Jun.1985, 1 female 7.8 mm cl (MNHN-IU-2011-5170, ex. MNHN-Pa 1087). – Balicasag Island , Bohol, tangle nets, 200–300 m, Dec.2000, 1 ovigerous female 25.6 mm cl ( NTOU M01572 ) . – PANGLAO 2004, station PN1, tangle nets, 29 May 2004, 5 females 24.3–29.2 mm cl ( NTOU M01573 ) ; station P4, 9°31.1'N, 123°41.5'E, 100 m, tangle nets, 31 May 2004, 1 ovigerous female 28.0 mm cl ( NTOU M01574 ) . – PANGLAO 2005, station CA2366 , 8°53.8'N, 123°16.4'E, 64 m, 26 May 2005, 1 female 26.6 mm cl ( NTOU M01575 ) .

Indonesia, CHALLENGER, station 192, Kai Islands , 5°49'15"S, 132°14'15"E, 256 m, 26 Sep.1874, female 23.0 mm cl, lectotype, 2 males 18.0–19.0 mm cl, paralectotypes ( BMNH 1888.22 ). – KARUBAR, station DW24, Kai Islands , 5°32'S, 132°51'E, 243– 230 m, 26 Oct.1991, 1 female 9.0 mm cl (MNHN-IU-2011-5171, ex. MNHN-Pa 1912); station DW 32, Kai Island, 5°47'S, 132° 51'E, 170–206 m, 26 Oct.1991, 1 female 8.1 mm cl (MNHN-IU-2011- 5155); station CP36, Kai Islands, 6°05'S, 132°44'E, 268– 210 m, 27 Oct.1991, 4 males 10.4–16.6 mm cl, 12 females 10.8–18.7 mm cl (MNHN-IU-2011-5154, ex. MNHN-Pa 1880) .

Îles Glorieuses, BENTHEDI, station 8 DR, 11°29.2'S, 47°18.2'E, 250 m, 19 Mar.1977, 1 ovigerous female 28.0 mm cl (MNHN-IU- 2011-5106, ex. MNHN-Pa 601).

Diagnosis. — Rostrum with sharp rostral tooth. Pregastric tooth absent while gastric tooth strong and highly elevated. Cardiac tooth slightly elevated, truncate or rarely represented by 2 weak and blunt tubercles. Cervical groove weak but not very narrow. Anterolateral, mediolateral and posterolateral teeth squamiform and flat except for anteriormost tooth ( Fig. 1A ). Abdomen with arborescent sculpture, without elevated median dorsal carina. Articulating surfaces of abdominal tergites II–V each bearing 1 or 2 transverse grooves, often with squamae. Arborescent sculpture on non-articulating surface of abdominal tergites I–V with longitudinal grooves rather parallel and not distinctly branched, giving impression of consisting of rows of large rectangular squamae ( Fig. 1B, C ); sometimes longitudinal grooves also interconnected by smaller squamae in between ( Fig. 1B ). Posterior margins of abdominal tergites I–III distinctly incised medially, that of tergite IV weakly or not (mostly) incised medially ( Fig. 1B, C ). Abdominal pleura II–IV acutely pointed posteroventrally. Anterior margin of antennal segment VI with 6 teeth. Antennal segment IV with outer margin bearing 2 large teeth; dorsal surface with 1 oblique carina; anterior margin armed with 1 large tooth, sometimes also with smaller teeth or denticles ( Figs. 1A , 2A ). Anterior margin of fused antennal segments II and III with anterior margin bearing 2 teeth, outer tooth larger, but not as large as rostral tooth. Only pereiopod III distinctly subchelate ( Fig. 2B, D ). Propodus of pereiopod IV with small to minute anteroventral tooth ( Fig. 2C, E ). Anterior part of thoracic sternum anteriorly produced and nearly truncate or somewhat bifurcate, with medial part “V”- shapedly sunken, lateral non-sunken part slightly narrower than median sunken part. Thoracic sternum with lateral parts not ridged or tuberculated, median fissure only sometimes present on thoracic sternite IV posterior to median sunken area ( Fig. 1D, E ). Last thoracic sternite without median tubercle, posterolateral angle with small tooth in males but unarmed in females.

Colouration. — Body generally light rusty brown, with squamae on carapace and anterior 2 abdominal somites more brownish ( Fig. 4A ). Articulate surface of abdominal tergite I with some longitudinal brown lines. Antennule with bluish brown markings. Eyes light brown.Abdominal somite VI and tail fan greyish white. Pereiopods dull yellow and covered with rusty brown bands.

Distribution. — Known with certainty from the Philippines, Indonesia, and Îles Glorieuses, probably also in Somalia, Kenya, Saya de Malha Bank, Seychelles and Hawaii (see “Remarks”), at depths of 64– 300 m.

Remarks. — Chelartus cultrifer is restricted to localities from the Philippines and southwards, so seems that its taxonomy would be straight forward since the type localities of the two subspecies in C. cultrifer are from Indonesia and the Philippines. Although the Indonesian and Philippine specimens examined are nearly identical, genetic analysis shown that there are two distinct sister clades in these populations ( Fig. 5 ). One clade consists of both Indonesian and Philippine material, while an Indonesian specimen is grouped with the specimen from Îles Glorieuses. The COI divergences between these two clades are 5.6–8.3%, whereas within each clade only 1.4–2.6% divergence is recorded (Table 2). The genetic difference between these two clades in C. cultrifer is quite large for decapod crustaceans in general ( Matzen da Silva et al., 2011) but somewhat lower than the usual specific difference for Scyllarinae (i.e., 12.5–15.8%; see Yang et al., 2008; Yang & Chan, 2010; Yang et al., 2011). Thus, it may be necessary to resurrect the subspecies in C. cultrifer . Unfortunately, the primary type specimens of both the nominate form and C. cultrifer meridionalis are old specimens (collected from 1874 and 1909, respectively) and failed to generate any genetic data.

Detailed examination of the specimens used for genetic analysis showed that the arborescent sculpture on the abdomen is more complicated in those specimens of the clade containing material from the Philippines. In these specimens, the rectangular squamae on the non-articulating surfaces are somewhat interconnected by smaller squamae ( Fig. 1B ). In the other clade, these smaller squamae are absent or rather indistinct ( Fig. 1C ). All the Philippines specimens examined, including the holotype of C. cultrifer meridionalis , bear these smaller squamae (see also Holthuis, 1960). The Indonesian specimens, however, usually do not have these smaller squamae except for the KARUBAR station DW 24 female, which has these squamae; this female is also genetically closer to the Philippine material. Nevertheless, the lectotype and paralectotypes of C. cultrifer do not have these small squamae ( Fig. 1C ). Thus, if C. cultrifer is to be subdivided, the nomino-typical form can probably be referred to those without interconnecting small squamae in the abdominal sculpture while the subspecies name, C. cultrifer meridionalis , can be applied to those having these interconnecting small squamae. More DNA workable specimens from various localities will be necessary to elucidate if there are indeed two subspecies in C. cultrifer and their exact morphological differences. On the other hand, re-examination of the other specimens identified as “ C. cultrifer ” in Holthuis (2002) will be necessary to ascertain the exact distribution of this species as discussed in the “Remarks” of the new species. However, it is pertinent to highlight that the “ Scyllarus cultrifer ” specimen reported by Barnard (1947, 1950, and originally reported as “ Scyllarus sordidus ” in Barnard, 1926) from Mozambique does not belong to Chelarctus but to Galearctus according to the shape of the anterior part of the thoracic sternum. Barnard’s (1926, 1947, 1950) Mozambique specimen is likely to be G. timidus ( Holthuis, 1960) but re-examination of the specimen will be necessary to determine its correct identity.

Figures

Fig. 1.A, B, D, Chelarctus cultrifer meridionalis (Holthuis, 1960), holotype, Philippines, female 22.0 mm cl, USNM 104525; C, E, Chelarctus cultrifer cultrifer (Ortmann, 1897), lectotype, Indonesia, female 23.0 mm cl, BMNH 1888.22. A, carapace, dorsal; B, C, abdomen, dorsal; D, E, thoracic sternum. Scale bars = 5 mm.

Fig. 2. A, D, E, Chelarctus cultrifer cultrifer (Ortmann, 1897), lectotype, Indonesia, female 23.0 mm cl, BMNH 1888.22; B, C, Chelarctus cultrifer meridionalis (Holthuis, 1960), Philippines, PANGLAO 2004, ovigerous female 28.0 mm cl, NTOU M01574. A, left antenna, dorsal; B, D, right pereiopod III; C, E, right pereiopod IV. Scale bars = 5 mm.

Fig. 4. A, Chelarctus cultrifer meridionalis (Holthuis, 1960), Philippines, PANGLAO 2005, female 26.6 mm cl, NTOU M01575; B, Chelarctus virgosus, new species, Taiwan, paratype male 22.3 mm cl, NTOU M01289.

Fig. 3. Chelarctus virgosus, new species. Holotype, Taiwan, ovigerous female 26.0 mm cl, NTOU M01571.A, carapace, dorsal; B, abdomen, dorsal; C, carapace, lateral; D, thoracic sternum; E, right pereiopod I; F, right pereiopod II; G, right pereiopod III; H, right pereiopod IV; I, pereiopod. Scale bars = 5 mm.

Fig. 5. Bayesian phylogenetic tree from partial segment (657 bp) of COI gene among Chelarctus species and outgroups. Posterior probability estimated by Bayesian inference shown on branches.