Ovalipes elongatus Stephenson & Rees, 1968

Published, First, 2009, New records of crabs (Decapoda: Brachyura) from the New Zealand region, including a new species of Rochinia A. Milne-Edwards, 1875 (Majidae), and a revision of the genus Dromia Weber, 1795 (Dromiidae), Zootaxa 2111, pp. 1-66 : 41-43

Ovalipes elongatus Stephenson & Rees, 1968

Fig. 20a

Ovalipes elongatus Stephenson & Rees, 1968: 232 , fig. 1E, pls 36B, 39D, 42E. — Stephenson 1972: 23. — Davie 2002: 460. — Takeda & Webber 2006: 200, fig. 5D.

Ovalipes bipustulatus — Chilton 1911: 554.

Not Ovalipes bipustulatus — Chilton & Bennett 1929: 755. [= Ovalipes catharus White , in White & Doubleday, 1843].

Material Examined. Kermadec Is: AQ489, 1 male, 13.3 mm x 11.9 mm, 1 female, 27.6 mm x 23.5 mm, Canterbury Museum, coll. W. R.B. Oliver, 1908. [Handwritten label, presumably by Chilton, shows “ Ovalipes bipustulatus M. Edw. ”, but also labelled as “ Ovalipes elongatus identified by Stephenson & Rees, 1966”.]; AQ2799, 1 male 9.0 mm x 8.0 mm, Canterbury Museum, coll. R. Bell 1909–10; AQ2445, 2 females, 29.1 mm x 24.5 mm, 30.1 mm x 25.7 mm, cast ashore Raoul I., Canterbury Museum, coll. J.H. Sorenson 27 July, 1944. Whangarei Harbour: 1 male, 10.3 mm x 8.3 mm, 35° 43ʹ S, 174° 19ʹE, benthic sled, WRE 621 CB, 21 Nov. 2002 ( NIWA 48729).

Tauranga Harbour: 2 males, 6.3 mm x 5.3 mm, 6.5 mm x 5.4 mm, 37° 39ʹS, 176° 10ʹE, TRG801 CB, 24 Feb. 2004 ( NIWA 48730 ) .

New Plymouth Harbour: 1 female, 8.6 mm x 7.0 mm, 39° 04ʹS, 174° 04ʹE, benthic sled, TK022 CB, 16 Apr. 2002 ( NIWA 48731 ) ; 1 juv., 6.0 mm x 5.4 mm, 39° 04ʹS, 174° 04ʹE, 2 NPL068 , 15 Mar. 2005 ( NIWA 48732 ) ; 3 juveniles, 5.5 mm x 5.2 mm, 5.6 mm x 5.3 mm, 6.0 mm x 5.4 mm, 39° 04ʹS, 174° 04ʹE, 2 NPL076 , 15 Mar. 2005 ( NIWA 48733 ) .

Comparative Material. Ovalipes catharus (White, in White & Doubleday, 1843): Little Akaloa Bay, Banks Peninsula: female, 12.5 mm x 10.3 mm, 43° 40ʹS, 173° 00ʹE, 3 m, Apr. 1, 2008, personal collection (see Fig. 20b).

Remarks. Chilton (1911) first reported this species from the Kermadec Is as “ Ovalipes bipustulatus M.- Edw.” stating that he had seen “Several small specimens from Sunday Is collected by Mr Oliver and one by Captain Bollons”. These specimens are presumably the ones now in the Canterbury Museum collection as AQ489 (see above). A label with these specimens states that they were verified as O. elongatus by Stephenson & Rees in 1966. The specimen, said by Chilton to be collected by Captain Bollons, may be the small male in AQ2799, but the collection is attributed on the label (not written by Chilton) to “R. Bell, 1909-10” (see above). This collection also includes 18 megalopae (3.7 mm x 4.9 – 4.6 mm x 6.4 mm) that may or may not belong to the same species, but the chelipeds are certainly close to those of O. elongatus . Takeda & Webber (2006) reported a further 33 specimens of O. elongatus in collections from the Kermadec Is held by Te Papa. Thus it seems that O. elongatus is quite common in the Kermadec Is The specimens reported here from Whangarei Harbour (35° 43ʹ S, 174° 19ʹE), Tauranga Harbour (37° 39ʹS, 176° 10ʹE) and New Plymouth Harbour (39° 04ʹS, 174° 04ʹE) are the first specimens of this species reported from mainland New Zealand, extending the range much further south than Lord Howe Is (31° 30ʹ S, 159° 00ʹE) and the Kermadec Is (30°S, 178° 30ʹE).

Chilton & Bennett (1929) also use O. bipustulatus (H. Milne Edwards, 1834) for Ovalipes specimens from NZ, but this is O. catharus (White, in White & Doubleday, 1843). Takeda & Webber (2006) included O. catharus in their list of crabs recorded from the Kermadec Is assuming that Chilton’s use of “ Ovalipes bipustulatus ” indicated the same species as found on the NZ mainland, but Stephenson & Rees showed that two different species were involved and as a result established the new species. O. elongatus Stephenson & Rees, 1968 is the only species of Ovalipes on the Kermadec Is

O. elongatus ( Fig. 20a) and O. catharus ( Fig. 20b) are easily separated by the following differences: the tips of the 4 teeth on the frontal carapace margin in O. elongatus project further than a line drawn across the front, connecting the tips of the post-orbital teeth on either side (in O. catharus these 4 teeth do not reach this line), the CW/CL = 1.19 – 1.25 (versus 1.30 – 1.37) and the anterolateral teeth are long, acute and directed anteriorly (versus short, triangular and not breaking up the even curve of the anterolateral margin). The maximum sizes reported for O. elongatus are CW = 38 mm (females), 15 mm males mm ( Stephenson & Rees, 1968) compared with 115 mm (females) and 150 mm (males) for O. catharus ( McLay 1988) . No large males have been reported for O. elongatus , but presumably they grow at least as large as the females. O. catharus , from the New Zealand mainland (and South Australia and Victoria), clearly grow to a much larger size than O. elongatus from Lord Howe Is and the Kermadec Is.

Ovalipes elongatus is another New Zealand crab that can produce sound (see Mursia microspina and Ocypode pallidula herein) by rubbing the ventral surface of the cheliped propodus across a plectrum on the dorsal margin of the second pereopods. Also Ovalipes catharus from the mainland can also produce sound (see Stephenson, 1969). These three genera each use different mechanisms to make sound and as they each belong to different families ( Portunidae , Calappidae and Ocypodidae respectively), it shows that sound production is the result of parallel evolution.

Distribution Ovalipes elongatus was formerly only known from Lord Howe I. and the Kermadec Is, but is now known to occur around the northern half of the North I. of New Zealand. O. elongatus is a species endemic to the Tasman Sea. Depth range is intertidal to 55 m.