European Journal of Taxonomy 140: 1-18

http://dx.doi.org/10.5852/ejt.2015.140

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2015 • Ng P.K.L. & Bouchet P.

Research article

um:lsid:zoobank.org:pub:A44ED7CD-AEC4-46F8-8361-796DD49D6CF6

Actaea grimaldii , a new species of reef crab from Papua New Guinea

(Crustacea, Brachyura, Xanthidae)

Peter K.L. NG 1 & Philippe BOUCHET 2

1 Lee Kong Chian Natural History Museum, National University of Singapore, Kent Ridge,

Singapore 119260, Republic of Singapore.

Email: [email protected] (corresponding author)

Unstitut de Systematique, Evolution, Biodiversite ISYEB, UMR 7205 - CNRS, MNHN, UPMC, EPHE,

Museum national d’Histoire naturelle, Sorbonne Universites,

57 rue Cuvier, CP 51, F-75252, Paris, France.

[email protected]

1 um:lsid:zoobank.org:author:8ACB5B5C-7DC3-43A7-82E4-420AD0FF7377

2 um:lsid:zoobank.org:author:FC9098A4-8374-4A9A-AD34-475E3AAF963A

Abstract. A new species of xanthid crab, Actaea grimaldii , is described from the coral reefs of

Papua New Guinea. This species has a distinctive red and white coloration and is closest to Actaea

spinosissima Borradaile, 1902, from the Indian Ocean. However, the new species can be distinguished

by the arrangement of spines on the carapace, chelipeds and ambulatory legs, and the structure of the

male gonopods. Actaea grimaldii sp. nov. has also been confused with A. polyacantha (Heller, 1861),

but differs markedly in the carapace armature.

Keywords. Crustacea, Xanthidae, Papua New Guinea, Actaea , new species.

Ng PK.L. & Bouchet P 2015. Actaea grimaldii , a new species of reef crab from Papua New Guinea (Crustacea,

Brachyura, Xanthidae). European Journal of Taxonomy 140: 1-18. http://dx.doi.org/10.5852/eit.2015.14Q

Introduction

In the 1970-1990s, extensive marine biology field work was carried out on the north coast of Papua New

Guinea: at Laing Island, in Hansa Bay, at King Leopold III Biological Station, and in the Madang Lagoon,

at a facility run by the Christensen Foundation. Several authors (e.g., Gosliner 1992; Thomas 1996)

highlighted the exceptionally high species richness of Madang Lagoon, which became a famous place

in marine biodiversity lore. Both King Leopold III Biological Station and the Christensen Foundation

facility ceased operations in the mid-1990s, and, as a result, marine biologists essentially stopped research

activities on the north coast of Papua New Guinea. However, in 2012 a large expedition, under the “Our

Planet Reviewed” programme, was hosted on the campus of the Divine Word University in Madang.

Anew wave of novel marine species descriptions (e.g., Friclce 2014; Rubio & Rolan 2014; Summers

et al. 2014; Ng & Anker 2014; Meyer-Wachsmuth et al. 2014; Macpherson & Robainas-Barcia 2015)

was generated by this multinational expedition which lasted two months and involved 110 participants.

Many more reports await publication. Between November 30 and December 2,2012, the expedition was

European Journal of Taxonomy 140: 1-18 (2015)

visited by Prince Albert II of Monaco, whose Foundation had made the expedition possible. During his

visit, the Prince was presented with a species of xanthid crab that, pending confirmation then, appeared

new to science. Its colour pattern was similar to the colours of the armorial of the Grimaldi family and,

with the Prince’s approval, we offered to name the species after his family if it was confirmed to be new.

The purpose of the present paper is to describe this new species of Actaea De Haan, 1833.

Actaea (type species Cancer granulatus Audouin, 1826; see Guinot & Cleva 2009) is a xanthid genus

typically associated with tropical coral reefs and currently containing 31 species (updated from Ng et al.

2008). The genus has been studied by Odhner (1925), Guinot (1968, 1969, 1976) and Serene (1984)

(see also Guinot & Low 2010). However, many Actaea species are not well known, and a revision of

Actaea s. str. is needed. One poorly known species is Actaea spinosissima Borradaile, 1902, originally

described from the Indian Ocean. This species has also been reported from Australia and the Moluccas

in eastern Indonesia by Odhner (1925) and Serene (1984), respectively. Examination of the type of A.

spinosissima shows that a series of specimens from Papua New Guinea, as well as Serene’s (1984)

specimen, should be referred to a new species, here named A. grimaldii.

Material and methods

Material examined is deposited in:

• Museum national d’Histoire naturelle, Paris, France (MNHN);

• Zoology Museum of Cambridge University, United Kingdom (CUMZ);

• Zoological Reference Collection of the Lee Kong Chian Natural History Museum (ex Raffles Museum

of Biodiversity Research), National University of Singapore (ZRC).

The abbreviations G1 and G2 refer to the male first and second gonopods, respectively. Measurements

provided (in millimetres) are of the maximum carapace width and length, respectively. The terminology

for the carapace regions follows that proposed by Dana (1852) (see also Serene 1984: fig. C).

Results

Infraorder Brachyura Latreille, 1802

Superfamily Xanthoidea MacLeay, 1838

Family Xanthidae MacLeay, 1838

Subfamily Actaeinae Alcock, 1898

Genus Actaea De Haan, 1833

Remarks

Although the subfamily Actaeinae has been well studied by many authors, one name that was missed by

most revisors is Actaeodius Klunzinger, 1913. For instance, the name is not listed in the revisionary studies

and compilations by Serene (1984) andNg etal. (2008). Klunzinger (1913: 231) established Actaeodius

(as “ Actaodius ”) when discussing the taxonomy of Actaea fragifera (White, 1848) and A. polyacantha

(Heller, 1861). He decided that these names were synonyms and described and illustrated the species as

“Actaodiusfragifer ”. Guinot (1976: 236-237) followed and treated Klunzinger’s “ Actaodiusfragifer ” as

a synonym of Actaea polyacantha. The status of the genus, however, has not been discussed. Although

Klunzinger (1913) did not specifically state which was the type species of Actaeodius, his synonymy of

the two treated species means that Chlorodius fragifer White, 1848 is the type species of the genus by

monotypy. Currently, the two species are regarded as distinct species of Actaea s. str. (see Odhner 1925;

Guinot 1976; Ng et al. 2008).

NG P.K.L. & BOUCHET P., New Actaea from Papua New Guinea

Actaea grimaldii sp. nov.

um:lsid:zoobank.org:act:A736C0FE-D2B4-4256-AB85-4370386B0231

Figs 1-5

Actaea peronii var. squamosa - Caiman 1900: 10 (not Actaea squamosa Henderson, 1893).

Actaea spinosissima - Odhner 1925: 59 (part). — Serene 1984: 115, pi. 14F. — Davie 2002: 511 (not

Actaea spinosissima Borradaile, 1902).

Diagnosis

Anterior surfaces of carapace regions (1M, 2M, 3M, 2L, 5L) covered with numerous short sharp

spines and sharp tubercles of varying sizes, 2M and 2L surface gently convex, not distinctly inflated in

frontal view, 2M separated by median longitudinal groove anteriorly, 4M lunate, with sharp granules;

IP flattened, divided into many smaller regions by shallow grooves, with distinct transverse groove

on anterior third, confluent with series of flattened granules on 3R, 2R and 1R (Figs 1, 2A, 3 A, 4A);

frontal margins lined by sharp granules, IF and 2F with many sharp spines which project anteriorly,

hiding frontal margin from dorsal view (Figs 1, 2A-B, 3A-B, 4A); anterolateral margin with 4 spines

(excluding external orbital spine), each with smaller spine or spines basal to it on sub-branchial surface

(Figs 1, 2A, 3A, 4A); suborbital and subhepatic regions covered with numerous small, sharp granules

(Figs 2B, 3B); third maxilliped with outer surfaces pitted (Fig. 5A); outer surfaces of chelipeds with

numerous sharp spines and sharp tubercles, with small, sharp granules interspersed, carpus ovate, inner

angle with several short, slightly curved spines, outer surface of chela with strong spines, inner surface

of chela with median spine and several smaller sharp tubercles and granules (Figs 1, 2A, C-D, 3A,

C-D); ambulatory legs short, outer surfaces of merus, carpus and propodus covered with sharp tubercles

or granules, dorsal margins of merus, carpus and dactylus with numerous sharp spines, ventral margin

of dactylus with subterminal tubercle, with scattered long, simple setae, some of which extend beyond

tip of dactylus (Figs 1, 2A, 3A, 4C); thoracic sternum with surface distinctly pitted (Figs IB, 5B); male

abdomen longitudinally narrow, surfaces of stemites 1-3 pitted (Fig. 5C); G1 elongate, gently sinuous,

distal part curves upwards (Fig. 5D-F).

Etymology

The species name is in honour of His Serene Highness Albert II, Prince of Monaco, patron of the

PAPUA NIUGINI Expedition and several other biodiversity expeditions of the “Our Planet Reviewed”

programme conducted by MNHN and Pro-Natura International. The red and white colour pattern of the

new species also alludes to the colours associated with the House of Grimaldi.

Type material

Holotype

PAPUA NEW GUINEA: Madang District, Expedition PAPUA NIUGINI, stn PB35, outer slope, south

of Sek Is., 05°07.0 , S 145°49.4 , E, 12 m, 4 Dec. 2012, 1 c J, 6.2 x 4.4 mm (MNHN IU 2013-921).

Paratypes

PAPUA NEW GUINEA: same data as holotype, 1 & 5.1 x 3.8 mm (ZRC, ex MNHN IU 2013-920);

Madang District, Expedition PAPUA NIUGINI, stn PR17, west of Kranlcet Is., 05°11.8 , S 145°48.8’E,

15m, 11 Nov. 2012,1 $, 10.2 * 7.8 mm (ZRC, ex MNHN IU 2013-1245); Expedition PAPUA NIUGINI,

stn PR05, Kranlcet Is., 05°11.3 , S 145°49.6 , E, 7 Nov. 2012, 1 $, 8.5 x 6.2 mm (MNHN IU 2013-222);

Expedition PAPUA NIUGINI, stnPB28, eastofKranketls., 05°11.9 , S 145°49.6 , E, 10m, 24 Nov. 2012,

1 young $, 6.7 x 4.9 mm (MNHN IU 2013-759).

European Journal of Taxonomy 140 : 1-18 ( 2015 )

Fig. 1 . Actaea grimaldii sp. nov., Papua New Guinea, colours in life. A-B. Paratype, c?, 5.1 x 3.8 mm

(ZRC, ex MNHNIU 2013-920). C. Holotype, 6.2 x 4.4 mm (MNHNIU 2013-921). D. Paratype, ?,

10.2 x 7.8 mm (ZRC, ex MNHN IU 2013-1245). E. Paratype, $, 8.5 x 6.2 mm (MNHN IU 2013-222).

F. Paratype, §, 6.7 x 4.9 mm (MNHN IU 2013-759). G— H. Paratype, §, 6.4 x 4.9 mm (ZRC, ex MNHN

IU 2013-1255). A-G, dorsal views of habitus; B, ventral view of habitus; H, frontal view of habitus.

NG P.K.L. & BOUCHET P., New Actaea from Papua New Guinea

Comparative material

Actaea spinosissima Borradaile, 1902

MALDIVES: Mahlos Atoll, 23 fathoms, J.S. Gardiner coll., holotype, S, 5.1 x 3.4 mm (juvenile, no

gonopods) (CUMZ 1.63106).

BRITISH INDIAN OCEAN TERRITORY: Great Chagos Bank, stn CH0666, outer reef, among dead

branching coral heads, 10 m. Brothers Island, C. Head & H. Koldewey coll., 28 Feb. 2013, 1 S, 8.9 x

6.6 mm (ZRC).

Actaeapolyacantha (Heller, 1861)

GUAM: southwest of Orote Peninsula, G. Paulay coll., 15-18 Apr. 2000, 1 $ (ZRC 2000.731).

PAPUA NEW GUINEA: Expedition PAPUA NIUGINI, stn PB17, outer slope, Sek Is., 05°04.9’S

145°49.3 , E, 26 m, 14 Nov. 2012, 1 ?, 6.4 x 4.9 mm (ZRC, ex MNHNIU 2013-1255).

Actaeaperonii (H. Milne Edwards, 1834)

AUSTRALIA: New South Wales, M. Ward coll., 2 $$ (ZRC 1969.12.27.3-4).

Description

Regions well demarcated, separated by distinct grooves, anterior surfaces (notably 1M, 2M, 3M, 2L, 5L)

covered with numerous spines and sharp tubercles of varying sizes; 2M and 2L surface gently convex,

does not appear inflated in frontal view; 2M separated by median longitudinal groove anteriorly; 3M

subtriangular, with sharp spines; 4M lunate, with sharp granules; IP flattened, divided into many smaller

regions by shallow grooves, with distinct transverse groove on anterior third, confluent with series of

flattened granules on 3R, 2R and 1R; 20 transversely narrow, low; 2P raised, surface rounded (Figs 1,

2A, 3A, 4A). Frontal margin bilobate, lobes separated by broad, U-shaped cleft; margins lined by sharp

granules; IF and 2F with many sharp spines which project anteriorly, hiding frontal margin from dorsal

view (Figs 1, 2A-B, 3A-B, 4A). Supraorbital margin with 3 distinct spines; orbit short, ovate; eye

completely filling orbit; peduncle short, stout, with several dorsal granules; cornea large, with granule

basally (Figs 2A-B, 3A-B, 4A-B). Anterolateral margin arcuate, with 4 spines (excluding external

orbital spine), each with smaller basal spine or spines on sub-branchial surface; posterolateral margin

gently concave, surfaces covered with small, flattened granules; posterior carapace gently sinuous, lined

with small, flattened granules (Figs 1, 2A, 3 A, 4A).

Suborbital margin with 5 or 6 small spines; suborbital and subhepatic regions covered with numerous

small, sharp granules; pterygostomian region almost smooth (Figs 1H, 2B, 3B). Antennules folding

laterally (Figs 2B, 3B). Antenna with basal article quadrate, with 1 large and 1 small, sharp granule,

mobile; flagellum short, at base of orbital hiatus (Figs 2B, 3B). Epistome transversely rectangular;

anterior margin granulated; posterior margin with prominent median triangle, lateral margins sinuous

(Figs 2B, 3B).

Third maxilliped relatively short; outer surfaces pitted; ischium subrectangular, with shallow but distinct

submedian sulcus, inner margin dentate; merus quadrate, distolateral angle not distinctly auricular; exopod

stout, distal end reaching to distolateral edge of merus, flagellum elongate, as wide as merus (Fig. 5A).

Chelipeds slightly asymmetrical; outer surfaces with numerous sharp spines and sharp tubercles, with

small, sharp granules interspersed; inner and outer surfaces with scattered short, simple setae (Figs 1,

2A, C-D, 3A, C-D). Basis-ischium lined with small granules. Merus short, rounded; dorso-distal spine

largest. Carpus ovate, inner angle with several short, curved spines (Figs 1, 2A, 3 A). Chelae short, stout,

palm longer than fingers, not pigmented black or dark brown; inner surface with median spine and

several smaller sharp tubercles and granules (Figs 2C-D, 3C-D). Pollex with 2 low, longitudinal ridges,

1 submedian groove; cutting edge with 3 or 4 large, blade-like teeth; tip subspatuliform (Figs 2C-D,

European Journal of Taxonomy 140 : 1-18 ( 2015 )

Fig. 2. Actaea grimaldii sp. nov., holotype, S, 6.2 x 4.4 mm (MNHNIU 2013-921), Papua New Guinea.

A. Dorsal view of habitus. B. Frontal view of carapace. C. Outer view of right chela. D. Outer view of

left chela.

NG P.K.L. & BOUCHET P., New Actaea from Papua New Guinea

Fig. 3. Actaea grimaldii sp. nov., paratype, §, 10.2 x 7.8 mm (ZRC, ex MNHNIU 2013-1245), Papua

New Guinea. A. Dorsal view of habitus. B. Frontal view of carapace. C. Outer view of right chela.

D. Outer view of left chela.

European Journal of Taxonomy 140 : 1-18 ( 2015 )

Fig. 4. Actaea grimaldii sp. nov., paratype, 10.2 x 7.8 mm (ZRC, ex MNHNIU 2013-1245), Papua

New Guinea. A. Dorsal view of carapace. B. Thoracic sternum showing vulvae. C. Right fourth

ambulatory leg.

NG P.K.L. & BOUCHET P., New Actaea from Papua New Guinea

Fig. 5. Actaea grimaldii sp. nov., holotype, S, 6.2 x 4.4 mm (MNHNIU 2013-921), Papua New Guinea.

A. Right third maxilliped (setae not drawn). B. Anterior thoracic sternum (sternites 1—4) and telson.

C. Abdominal somites 1-6. D. Ventral view of left Gl.E. Ventral view of distal part of left Gl. F. Dorsal

view of distal part of left Gl. G. Left G2. Scale bars: A, D, G = 0.5 mm; B-C = 1.0 mm; E-F = 0.1 mm.

European Journal of Taxonomy 140 : 1-18 ( 2015 )

3C-D). Dactylus with 1 distinct low, longitudinal ridge, 1 submedian groove; upper margin with 2-4

spines on proximal half, cutting edge with 2 larger teeth on proximal half, distal half with 2 or 3 low

teeth; tip subspatuliform (Figs 2C-D, 3C-D).

Ambulatory legs short, stout; second pair longest; fourth pair shortest (Figs 1, 3A). Basis-ischium lined

with small granules. Outer surfaces of merus, carpus and propodus covered with sharp tubercles or

granules (Figs 1, 2A, 3A, 4C). Merus with dorsal margin armed with numerous sharp spines which

gradually become smaller proximally, distal one largest; ventral margin lined with small, sharp granules

(Figs 1, 2A, 3A, 4C). Dorsal margins of carpus and propodus with several sharp spines; ventral margin

of carpus with sharp granules; ventral margin of propodus with sharp spines (Figs 1, 2A, 3A, 4C).

Dactylus gently curved, surface covered with small, sharp granules; ventral margin with relatively larger

subterminal tubercle; tip corneous; surfaces with scattered long, simple setae, those on second to third

legs may be very long, extending well beyond tip of dactylus (Figs 1, 2A, 3A, 4C). Dactylo-propodal

lock well developed; distal margin of propodus with rounded median projection that overlaps ball-like

swelling on proximal margin of dactylus (Fig. 4C).

Thoracic sternum with surface distinctly pitted (Figs IB, 5B). Thoracic sternites 1 and 2 completely fused;

sternites 2 and 3 separated by distinct transverse suture; sternites 3 and 4 completely fused except for

lateral cleft (Figs IB, 5B). Sternoabdominal cavity deep, reaching to median part of sternite 4 (Figs IB,

5C). Male abdominal locking mechanism a knob-like process, on anterior third of sternite 5.

Male abdomen longitudinally narrow; surfaces of sternites 1-5 pitted (Fig. 5C). Somites 1 and 2

trapezoidal, completely covering surfaces of thoracic sternum between coxae of last pair of ambulatory

legs, sternite 8 completely covered; somites 3-5 completely fused, median sutures not discernible; lateral

margins concave; somite 6 rectangular, lateral margins gently sinuous, slightly longer than telson; telson

triangular, lateral margins gently sinuous, tip rounded (Fig. 5C).

G1 elongate, gently sinuous, distal part curves upwards, subdistal surfaces with numerous long setae and

spinules (Fig. 5D-F). G2 short, c. quarter of length of Gl; proximal part sinuous, distal part spatuliform

(Fig. 5G).

Females and variation

The females agree with the males in a lm ost all non-sexual characters. A female measuring 6.7 x 4.9 mm

(MNHNIU 2013-759) is still immature, with the abdomen triangular in shape. An adult female, 10.2 x

7.8 mm (pleopods fully setose, ZRC, ex MNHN IU 2013-1245), has an ovate abdomen that covers about

half the surface of the thoracic sternum. The vulvae are small, positioned on the anterior half of sternite

6 submedially and each has a distinct opercular cover in the form of a narrow plate (Fig. 4B). There is

hardly any variation in the diagnostic characters, although some of the specimens (e.g., ZRC, ex MNHN

IU 2013-1245) are twice the size of the smaller crabs (e.g., ZRC, ex MNHN IU 2013-920).

The long, simple setae on the ambulatory legs are easily broken, and while obvious in fresh specimens

(Fig. 1), they are often lost in preserved material. The holotype male has a developed Gl (Fig. 5D-F) but

does not appear to be fully mature. While the setae on the subdistal part of the Gl are long (Fig. 5E-F),

they are simple and not plumose as is typical for actaeine gonopods (cf. Guinot 1976).

Colour

In life (Fig. 1), the colour is a striking bright orange to red across the median part of the carapace, with

the lateral regions white. There may be patches of white on the gastric and adjacent regions in smaller

specimens. The legs are banded red and white, and the chelipeds are red and white, with parts yellowish-

white in colour. The fingers of the chela are reddish-orange basally and white at the tips. The ventral

surfaces are white, but abdominal somites 1 and 2 may have large patches of red.

NG P.K.L. & BOUCHET P., New Actaea from Papua New Guinea

Distribution

This species is known for certain from the Moluccas and Papua New Guinea, and is probably also

present in Australia.

Discussion

There are a group of Actaea species which have numerous small and large spines on their dorsal carapace

surface, chelipeds and/or legs: A. calculosa (H. Milne Edwards, 1834) (= Ewcanthus tuberculosus Miers,

1884), A. catalai Guinot, 1976, A. flosciilata A1 cock, 1898, A. fragifera (White, 1848), A. glandifera

Rathbun, 1914, A. hystrix Miers, 1886, A. occidentals Odhner, 1925, A. peronii (H. Milne Edwards,

1834), A. perspinosa Borradaile, 1902, A. petalifera Odhner, 1925, A. polyacantha (Heller, 1861) (=

Xantho spinosus Hess, 1865), A. spinosissima Borradaile, 1902, and A. squamidosa Odhner, 1925 (see

Guinot 1976: pis 12-14; Serene 1984: pi. 14D-F).

Fig. 6. Actaea spinosissima Borradaile, 1902, holotype, 5.1 x 3.4 mm (CUMZ 1.63106). Dorsal view

of habitus, photographed from slightly different angles.

European Journal of Taxonomy 140 : 1-18 ( 2015 )

The present new species, however, has distinct anterolateral spines (not granulated or spiniform lobes),

a character shared only with A. floscnlata, A. fragifera , A. glandifera , A. perspinosa , A. polyacantha ,

A. spinosissima and A squamulosa (cf. Guinot 1976: pi. 13, figs 2,4-7, pi. 14, fig. 3). Actaea squamulosa

is distinctive in that it has short anteorolateral spines and only low granules and rugosities on the dorsal

carapace surface, and has very stout cheliped fingers (Guinot 1976: pi. 13, figs 7-8). As to the 1L, 3L

and 4L of the carapace possessing sharp spines, the new species shares this character with A. glandifera ,

A. perspinosa , A. polyacantha and A. spinosissima.

With regard to the general carapace facies and armature, A. grimaldii sp. nov. is most similar to

A. polyacantha (cf. Guinot 1976: pi. 13, fig. 6) and A spinosissima (cf. Borradaile 1902: fig. 55; Odhner

1925: pi. 4, fig. 4; present Figs 5-6). Actaea polyacantha , however, has the granules on 1M, 2M and

3M flattened, low and rounded (cf. Guinot 1976: pi. 13 fig. 6); these areas have spiniform granules and

spines in A. grimaldii sp. nov. In addition, their G1 structures are quite different. The distal part of the

G1 in A. polyacantha is formed into a pronounced lobe (Guinot 1976: fig. 40B, b) but in A. grimaldii sp.

nov., the distal part of the G1 is turned upwards and tapers gradually to a sharp tip (Fig. 5E-F).

The identity of A. spinosissima Borradaile, 1902 is more problematic and its G1 structure has not

been figured before. Actaea spinosissima s. str. is now known for certain only from the western Indian

Fig. 7. Actaea spinosissima Borradaile, 1902, holotype, 5.1 x 3.4 mm (CUMZ 1.63106), Maldives.

A. Frontal view of carapace. B. Anterior thoracic sternum (sternites 1—4), telson and abdominal somite 6.

C. Outer view of left chela.

NG P.K.L. & BOUCHET P., New Actaea from Papua New Guinea

Fig. 8. Actaea spinosissima Borradaile, 1902, 8.9 x 6.6 mm (ZRC), Chagos Islands A. Dorsal view

of habitus. B. Frontal view of carapace. C. Outer view of right chela. D. Outer view of left chela.

European Journal of Taxonomy 140: 1-18 (2015)

Ocean. Described from the Maldives by Borradaile (1902: 256, fig. 55), it was recorded again shortly

after that by Rathbun (1902: 128) who also found two juveniles from these islands. Rathbun (1911)

subseqently recorded another juvenile female from Cargados Carajos islands in Mauritius in the western

Indian Ocean, but provided no figures. Serene (1984: 114) noted that the record of a male specimen

of “A. spinosissima ” from St. Brandon in Mauritius by Ward (1942: 87) is A. polyacantha instead.

Whether this also includes Rathbun’s (1911) specimens cannot be ascertained. The other records of

Fig. 9. Actaea spinosissima Borradaile, 1902, 8.9 x 6.6 mm (ZRC), Chagos Islands A. Dorsal view

of carapace. B. Thoracic sternum showing vulvae. C. Right fourth ambulatory leg.

NG P.K.L. & BOUCHET P., New Actaea from Papua New Guinea

this species by Odhner (1925: 59, pi. 4, fig. 4), Serene (1961: 206, 1968: 79), Guinot (1967: 559, 1969:

238, 1971: 1071, 1976: 233, pi. 13, fig. 3) and Ng et al. (2008: 195) merely list or discuss the species

and do not record fresh material. Fortunately, among recent material examined from the Chagos Islands

in the western Indian Ocean is an adult male (Figs 8-9) that agrees well with the holotype male of

A. spinosissima', its G1 is figured here (Fig. 10). Although the specimen is slightly faded, the remaining

colour and pattern suggest they are similar to those of A. grimaldii sp. nov.

The specimen figured as LL A. spinosissimcT by Serene (1984: 115, pi. 14F) (a male 6.0 x 4.6 mm from

Moluccas) agrees well, even in the colour and pattern (cf. Fig. 1), with what is described as A. grimaldii

sp. nov. and they appear to be conspecific. Caiman (1900: 10) recorded a male specimen measuring 14.0

by 10.0 mm that he provisionally attributed to “ Actaea peronii var. squamosa ” and noted as differing

from A peronii by its sharp and spiniform anterolateral teeth. Odhner (1925: 59) and Serene (1984: 114)

suggested that his record was probably A. spinosissima , but could not be sure as he did not have the

specimen and Caiman did not figure the species. Davie (2002: 511) accepted Serene’s identification and

listed this species from Australia. On the basis of geography, it seems Caiman’s specimen is more likely

to belong to A. grimaldii sp. nov. than to A. spinosissima s. str.

Fig. 10. Actaea spinosissima Borradaile, 1902, $, 8.9 x 6.6 mm (ZRC), Chagos Islands A. Ventral view

of left Gl. B. Ventral view of distal part of left Gl. C. Dorsal view of distal part of left Gl. D. Feft G2.

Scale bars: A, D = 0.5 mm; B-C = 0.1 mm

European Journal of Taxonomy 140: 1-18 (2015)

Actaea grimaldii sp. nov. differs from the type of A. spinosissima s. str. in several key characters: the

granules on 1M, 2M, 3M, 2L and 5L are conical and sharp (Figs 1, 2A, 3A, 4A) (vs granules raised but

tips broad and rounded in A. spinosissima , Fig. 6); the IP and tranverse granules adjacent to it are raised

and rounded (Figs 1, 2A, 3A, 4A) (vs area and granules distinctly flattened in A. spinosissima , Fig. 6);

2P is raised and rounded (Figs 1, 2A, 3A, 4A) (vs area flattened in A. spinosissima , Fig. 6); the surfaces

of 2M and 2L are gently convex (Figs 2B, 3B) (vs areas distinctly more inflated in A. spinosissima ,

Fig. 7A); the subhepatic and suborbital regions are covered with numerous granules (Figs 2B, 3B) (vs

these regions are covered with relatively fewer and lower granules in A. spinosissima , Figs 7A, 8B), the

spines on the anterolateral margin and carpus of cheliped acute and straight or gently curved (Figs 1,2A,

3A) (vs spines relatively stouter and more distinctly curved anteriorly in A. spinosissima , Fig. 6); the

spines on the chela are relatively slender (Figs 2C, D, 3C, D) (vs stouter in A. spinosissima , Fig. 7C); the

ambulatory merus is proportionately longer (Figs 2A, 3B, 4C) (vs distinctly shorter in A. spinosissima ,

Figs 6, 8A, 9C); and the G1 is proportionately stouter (Fig. 5D) (vs more slender in A. spinosissima ,

Fig. 10A).

Acknowledgements

The “Our Planet Reviewed” PAPUA NUIGINI Expedition was organized by MNHN (marine Principal

Investigators: Philippe Bouchet, Claude Payri and Sarah Samadi), Pro Natura International, and Institut

de Recherche pour le Developpement, in partnership with University of Papua New Guinea; with

funding and support from the Prince Albert II of Monaco Foundation, Total Foundation, Foundation

EDF, Stavros Niarchos Foundation, Entrepose Contracting, and in-kind support from the Divine

Word University; the expedition operated under a permit from the Papua New Guinea Department of

Enviro nm ent and Conservation. The authors thank Matthew Lowe (CUMZ) for permission to examine

the type of Actaea spinosissima , and Paul Clark (The Natural History Museum, London) for facilitating

the loan. The colour photographs are courtesy of Tin-Yam Chan (National Taiwan Ocean University)

and Arthur Anker (National University of Singapore). Thanks are also due to Daniele Guinot (MNHN)

and several anonymous reviewers for their helpful co mm ents on the manuscript.

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Manuscript received: 25 May 2015

Manuscript accepted: 10 September 2015

Published on: 29 September 2015

Topic editor: Rudy Jocque

Desk editor: Charlotte Thionois

Printed versions of all papers are also deposited in the libraries of the institutes that are members of the

EJT consortium: Museum national d’Histoire naturelle, Paris, France; Botanic Garden Meise, Belgium;

Royal Museum for Central Africa, Tervuren, Belgium; Natural History Museum, London, United

Kingdom; Royal Belgian Institute of Natural Sciences, Brussels, Belgium; Natural History Museum of

Denmark, Copenhagen, De nm ark