Sundathelphusa philippina (von Martens, 1868 )

Husana, Daniel Edison M. & Ng, Peter K. L., 2019, On the identity of Sundathelphusa philippina (von Martens, 1868) (Decapoda: Brachyura: Gecarcinucidae) from the Philippines, with descriptions of two new species, Zootaxa 4585 (2), pp. 315-331 : 316-321

publication ID	https://doi.org/ 10.11646/zootaxa.4585.2.5
publication LSID	lsid:zoobank.org:pub:6E61D5EE-E3AD-44EC-9AB3-C7B3E303BF92
DOI	https://doi.org/10.5281/zenodo.5466959
persistent identifier	https://treatment.plazi.org/id/C6560C5A-6B29-FF8F-E7FE-FB6AFDA0F8EE
treatment provided by	Plazi
scientific name	Sundathelphusa philippina (von Martens, 1868 )
status

Treatment

Sundathelphusa philippina (von Martens, 1868) View in CoL

( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 ; 6A, C, E, G, I, J View FIGURE 6 ; 9A, B View FIGURE 9 )

Thelphusa philippina von Martens, 1868: 608 ; A. Milne-Edwards 1869: 168.

Potamon (Potamonautes) philippinum — Ortmann 1897: 304, 307 (part).

Potamon philippinum —De Man 1898: 37 (part); 1902: 558.

Potamon (Potamon) philippinus — Rathbun 1904: 304 (part).

Sundathelphusa philippina View in CoL - Bott 1970: 78, pl. 28 fig. 57, pl. 32 figs. 1–3; Cabrera 1975: 602; Takeda 1987: 101 (part), pl. 12 (top); Ng & Sket 1996: 697 (in part); Ng et al. 2008: 73 (list); Mendoza & Naruse 2010: 63 (in part; list).

Sundathelphusa spelaeophila Stasolla, Abbarchi & Innocenti, 2015: 449 View in CoL View Cited Treatment , figs. 1A–C, 2A–E.

Material examined. Lectotype: ♂ (42.8 × 34.8 mm), ZMB 1055 View Materials a, Lokilokon, Samar Island , coll. F. Jagor. Paralectotypes: 4♂♂, 1 young ♀, ZMB 1055 View Materials b, same data as lectotype ; 1 ♂ (51.4 × 42.8 mm), ZMB 1050 View Materials , Calbiga, stream near Lokilokon (formerly Loquilocun) Samar Island (original label: Philippinen, Insel Samar, Calbigaufluss bei Loquilocum), coll. F. Jagor. Additional material : 2 ♀♀, NMCR 239, Sarawang , Matuginao, Samar Island, coll. G.E. Edano, 4 December 1941 ; 1 ♂ (44.9 × 35.9 mm), ZRC 2017.1062 View Materials , Lobo Cave , Jiabong , Western Samar province, Samar Island, 11°46.786’N 124°55.732’E, coll. D.E. Husana, 1 August 2006 GoogleMaps ; 1 ♂, 2 ♀♀ (35.7 × 28.7 mm, 39.9 × 31.8 mm, 47.6 × 37.9 mm), ZRC 2017.1058 View Materials , Panghuyaman Cave , Daram Island , Western Samar province (west of Samar Island), coll. D.E. Husana, 7 August 2006 ; 5 ♂♂ (30.8 × 24.8 mm, 20.3 × 16.7 mm, 18.0 × 15.0 mm, 16.9 × 13.9 mm, 14.1 × 12.3 mm), ZRC 2016.0107 View Materials , Brgy San Rafael, Hinabangan, Samar Island , coll. A.C. Diesmos ; 1 male, MNHN B28509, in cave, Samar Island , no date ; 1 ♀, ZRC 2016.0109 View Materials , Baybay , Leyte, coll. A.C. Diesmos, August 2002 ; 1 ♂ (33.8 × 31.3 mm), 1 ♀ (38.2 × 31.1 mm), ZRC 2017.1259 View Materials , 1 View Materials ♀ (39.1 × 31.3 mm), NSMT-Cr25886, Bari , Jaro, Leyte Island, coll. S. Shokita et al., 19 September 1985 ; 1 ♂ (19.5 × 15.8 mm), NMCR 13, Kasarugingan , Ormoc, Leyte Island, ca. 10°57'N 124°41'E, coll. G. Edano, March 1950 GoogleMaps ; 2 ♂♂, 1 ♀, NSMT , 3 ♂♂ (33.8 × 27.1 mm, 51.3 × 40.4 mm, 53.4 × 42.5 mm), 1 ♀ (51.7 × 42.2 mm), ZRC 2009.0409 View Materials , Binang-kaan River , Buhi, ca. 13°26'N 123°31'E, Camarines Sur, Luzon Island, coll. N. Gapas, 19 August 1985 GoogleMaps ; 1 young ♂ (15.3 × 13.0 mm), 1 young ♀ (20.4 × 16.9 mm), ZRC 2017.1059 View Materials , Borabod stream, Buhi, ca. 13°26'N 123°31'E, Camarines Sur, Luzon Island, coll. N. Gapas, 19 August 1985 GoogleMaps . All locations in the Philippines .

Description. Carapace trapezoidal, widest at anterior quarter, dorsal surface convex longitudinally, dorsoventrally depressed, regions distinct ( Figs. 1A, B View FIGURE 1 ; 3E View FIGURE 3 ; 6A, E View FIGURE 6 ). Frontal region sloping anteroventrally; anterolateral regions inflated dorsolaterally, smooth to gently cristate; cervical grooves deep; H-shaped gastric groove deep; epigastric cristae distinct, edges rough, separated by distinct median furrow; postorbital cristae, sharp but low; epigastric and postorbital cristae not confluent; epibranchial teeth and postorbital cristae not confluent, separated by gaps ( Fig. 1A, B View FIGURE 1 ). Frontal margin broadly protruded, two lobes clearly separated with broad median concavity; external orbital tooth produced anteriorly, outer margin longer than inner margin; epibranchial tooth distinct, triangular, well separated from external orbital tooth, tapering anteriorly, surface flat, margin not curving dorsally; anterolateral margin convex, crest low, not clearly visible even when viewed laterally, not clearly demarcated from posterolateral margin; posterolateral margin straight, converging gradually towards posterior margin of carapace ( Figs. 1A, B View FIGURE 1 ; 6A, C, G View FIGURE 6 ). Frontal median triangle complete; dorsal and lateral margins distinct, smooth; dorsal margin more produced anteriorly than lateral margins ( Fig. 2F View FIGURE 2 ); orbit well demarcated; supraorbital margin smooth; infraorbital margin protruded anteriorly granulated; outer edge reaching, fused with anterolateral margin; suborbital and subbranchial regions covered with scattered oblique long, short striae; pterygostomial region smooth with oblique ridges on upper outer part ( Figs. 1C View FIGURE 1 ; 6E View FIGURE 6 ). Posterior margin of epistome with three lobes, median lobe large, subtriangular, more produced; lateral lobes wider and protruded, placed more posteriorly than median lobe ( Figs. 1C View FIGURE 1 ; 2G View FIGURE 2 ; 6G View FIGURE 6 ). Eyes well developed, occupying entire orbit ( Figs. 1 View FIGURE 1 A–C; 6A, C, E, G).

Ischium of third maxilliped rectangular, with distinct submedian sulcus close to mesial margin; merus quadrate, anteroexternal angle convex, anterior margin slightly concave; tip of exopod reaching midpoint of outer margin of merus, with long flagellum reaching beyond mesial margin ( Fig. 1C, E View FIGURE 1 ).

Adult male chelipeds stout, subequal; dorsal margin of merus serrated, dorsal margin with distinct subdistal tooth; carpus with strong distal inner angle, flattened dorsoventrally, laterally fringed with proximal teeth; palm equal in length with finger; ventral margin granulated; fingers robust, cutting edges with teeth of various sizes, largest medially, smaller on distal and proximal parts ( Fig. 1F View FIGURE 1 ).

Ambulatory legs not elongate ( Figs. 1A View FIGURE 1 ; 9A, B View FIGURE 9 ), second leg longest; anterior margin of merus serrated, without subdistal tooth or spine, posterior margins smooth; carpus short, with longitudinal submedian ridge on dorsal and ventral surfaces of all legs except on fourth leg that lacks ventral ridge, with barely visible dorsal ridge, widened distally, outer margins indistinctly serrated; propodus with rows of spines on inner and outer margins, shorter on outer margin; dactylus with rows of spines on all margins, spines of both outer and inner margins of dactylus almost equal in length ( Figs. 1A View FIGURE 1 ; 9B View FIGURE 9 ).

Male sternopleonal cavity reaching to level of proximal quarter of coxae of chelipeds ( Fig. 1D View FIGURE 1 ). Adult male pleon narrow, T-shaped; somite 1 very short, proximal and distal margins sinuous; somite 2 transversely subrectangular; somites 3–5 narrow gradually; lateral margins of somite 3 convex, lateral margins of somites 4 and 5 slightly concave; somite 6 rectangular, longer than broad, lateral margins slightly concave; telson subtriangular, longer than broad, lateral margin concave medially, rounded distally ( Figs. 1D View FIGURE 1 ; 2E, U, V, W View FIGURE 2 ).

G1 relatively slender; subterminal segment, almost straight, tapering; terminal segment obliquely bent outwards at midpoint, outer margin concave, tapering, cylindrical, slightly setose ( Figs. 2 View FIGURE 2 A–D, H–S; 6I, J). G2 shorter than G1, terminal segment long, about half length of subterminal segment ( Fig. 2T View FIGURE 2 ).

Remarks. Von Martens (1868) described S. philippina from an unspecified number of specimens from the islands of Samar and Luzon. All the specimens he examined are, therefore, syntypes. Bott (1970: 79) designated a male measuring 43 × 33 mm from the type series (ZMB 1055) as the lectotype. The bottle catalogued as ZMB 1055 contains a 42.8 × 34.8 mm male specimen from “Loquilocun” (in Samar) ( Fig. 1A View FIGURE 1 , C–F) with the label “ lectotype ”, and it agrees well with the figures and measurements given by Bott (1970: 79) for the lectotype, and is here recognized as such.

The type locality “Loquilocun” is a small village (also known as barangay) in Paranas town (formerly known as “Wright” town) upstream of Ulot river in Samar and has the following coordinates: 11°48’30.0”N, 125°06’24.0”E. The spelling of the village has already changed to “Lokilokon” in recent years; hence the old name cannot be found in modern maps and digital references. As for the data on the old labels, we note that it is a common practice in the Philippines to name a stream or a river after the name of a town or a village. We are of the opinion that the name “Calbiga” on the old Jagor labels is imprecise because Lokilokon is actually located at Paranas town, which is about 30 km away. We believe that the collector F. Jagor used this name only because he had passed Calbiga town on his way to Lokilokon village during his expedition

The specimen from Camarines Sur, a province located in the Bicol peninsula in the southeastern part of Luzon Island, just north of Samar Island, could be a different species from S. philippina given its geographic location. But until comparative specimens become available, we regard the Sundathelphusa populations in the two adjacent islands as one taxon for the time being.

The taxonomic history of S. philippina is confusing as various authors have mixed up material together. Bott (1970: 79) stated that only specimens from Samar, Mariveles and Bohol can be confidently referred to S. philippina sensu stricto. Material that had been identified as this species by Bürger (1894: 4), De Man (1898: 437), Ortmann (1897: 304), Rathbun (1904: 304) and Balss (1934: 177) from Luzon, Negros and other locations were mixed, and/ or have been confused with Sundathelphusa grapsoides (H. Milne Edwards, 1853) instead (see also Balss 1937: 153). Bott (1970) also synonymized Potamon (Potamon) montanoanus Rathbun, 1904 , and Potamon (Potamon) mistio Rathbun, 1904 , under S. philippina , although both species are from mountains in the island of Mindanao which is far south from his localities. Ng et al. (2008) treated both species as distinct from S. philippina sensu stricto although no reasons were provided (see also Mendoza & Naruse 2010). Mendoza & Sy (2017) recently described a new Sundathelphusa species from Mindanao and redescribed S. mistio and S. montanoanus from the types and showed they are distinct taxa.

Bürger’s (1894: 4) record of “ Telphusa philippina ” is a subsequent record from von Martens and does not constitute an original description as indicated in Ng et al. (2008: 73), and so poses no homonymy issues. We examined the extant Bürger (1894) material in the ZMB; his material from Agno River in Luzon are all S. grapsoides . The material he listed from Bohol was referred to a new species, S. boex , by Ng & Sket (1996). Although Ng & Sket (1996) treated the material from Cebu as “ S. philippina ”, we now show that they actually belong to a separate species, here described as S. cebu sp. nov. (see discussion later). Bürger’s specimen from Mariveles (in Luzon) is actually an undescribed small species, which will be described at a later stage. The specimen figured by him ( Bürger, 1894: pl. 1 fig. 3) is clearly not S. philippina sensu stricto as understood at present and resembles the new species from Mariveles. But because he did not indicate the origins of the specimen figured, we are unsure of its identity. As far as we know, Bürger (1894) did not have specimens of S. philippina sensu stricto as defined here.

The species named as “ Potamon (Telphusa) philippina Martens, 1869 ”, in Estampador’s (1959) checklist of the decapod crustaceans of the Philippines is definitely not S. philippina because his localities were all in the northern region of Luzon Island including Camiguin, an islet north of Luzon, not to be confused with the more famous Camiguin island located north of Mindanao.

In addition, we have specimens from Quirino province, in northern Luzon, which superficially resemble S. philippina but are distinct in their carapace and ambulatory morphology as well as G1 characters. They are here described as S. quirino sp. nov.

The good series of specimens of S. philippina sensu stricto from Samar Island allow us to determine the variation in this species. Significant allometric changes are often observed with increasing size, in particular with the form of the carapace. In S. philippina sensu stricto, smaller specimens (e.g., 14.1 × 12.3 mm, ZRC 2016.0107) have a subquadrate carapace with the regions of the dorsal surface (notably the branchial region) relatively less convex and the surface more rugose ( Fig. 3A View FIGURE 3 ). The G1s of these smaller males, although appearing to be functional, are also usually relatively straighter, with the distal half less distinctly curved ( Fig. 3B View FIGURE 3 ). As specimens get larger (e.g., 30.8 × 24.75 mm, ZRC 2016.0107), the anterolateral and branchial regions gradually become more inflated with the surface smoother, and the carapace becomes more transversely ovate with the posterolateral margins more prominently convergent ( Fig. 3A View FIGURE 3 ). In these larger males, the G1 is also relatively stouter and the distal half becomes prominently curved ( Fig. 3B View FIGURE 3 ). The changes in carapace morphology are also evident in the female specimens examined here.

The presently observed size-related changes in carapace shape, surface morphology and G1 structure indicate that Sundathelphusa spelaeophila Stasolla, Abbarchi & Innocenti, 2015 , is a junior subjective synonym of S. philippina sensu stricto. The former species was described from four relatively small males (holotype, 15.9 by 14.1 mm, MZUF 3920; paratypes, 11.7 × 10.6 mm MZUF 4273, 15.4 × 12.9 mm NMCR 40102, 16.8 × 14.7 mm MZUF 3927) from Can Gortio Cave and “SNAZ 1” Cave, Barangay Matalud, San Jorge municipality, Samar province, Philippines. The type locality of S. spelaeophila is actually only about 15 kilometers north of Lobo Cave where one of the specimens of S. philippina (ZRC 2017.1062) was collected. We also obtained specimens of S. philippina sensu stricto from the shallow part of the caves (Lobo and Daram Caves), similar to the habitat of S. spelaeophila reported by Stasolla et al. (2015). The map for the type locality of the S. spelaeophila has an inaccuracy; the correct location of Lobo cave is actually that indicated as Langun cave on their map ( Stasolla et al. 2015: fig. 3) (see Husana et al. 2009: fig. 1).

The presence of S. philippina in caves is not significant as the species is clearly not a stygobiont, not possessing any of the attributes associated with such fauna (see Holthuis 1986; Guinot 1988, 1994). True stygobiont species of Sundathelphusa with loss of carapace pigmentation, reduced eyes and elongated ambulatory legs are known from the Philippines (see Husana et al. 2009; Takeda & Ng 2001). Sundathelphusa philippina is clearly an epigeal species that roams around surface streams at night and just occasionally wanders into cave habitats for shelter during the day. From our extensive field collections and investigations, we observed that the habitat range of this species is from the shallow part of the caves in karstic areas to small surface streams with stagnant to slow-moving freshwater. They mainly stay under the submerged rocks, logs or leaves in the water and only come out in the open to forage.