THE RAFFLES BULLETIN OF ZOOLOGY 2007
THE RAFFLES BULLETIN OF ZOOLOGY 2007 Supplement No. 16: 47–53
Date of Publication: 31 Dec.2007© National University of Singapore

ON TWO SPECIES OF DEEP-SEA HOMOLODROMOID CRABS OF THE GENUSDICRANODROMIA (CRUSTACEA: DECAPODA: BRACHYURA: HOMOLODROMIIDAE)
FROM THE PHILIPPINES, INCLUDING ONE NEW SPECIESPeter K. L. Ng
Department of Biological Sciences, National University of Singapore,
14 Science Drive 3, Singapore 117543, Republic of Singapore
Email: dbsngkl@nus.edu.sg

Tohru Naruse
Department of Biological Sciences, National University of Singapore,
14 Science Drive 4, Singapore 117543, Republic of Singapore

ABSTRACT. – Two species of deep sea homolodromiid crabs, Dicranodromia martini and D. chenae, newspecies, are recorded from the Philippines. Dicranodromia martini shows some morphological variation inits pereiopods: larger specimens have relatively shorter dactyli of the second and third pereiopods; and thelargest specimen lacks a movable spine on the extensor margin of the fifth pereiopod, a feature present insmaller specimens. The first male gonopod of D. martini is described for the first time. A new species,
Dicranodromia chenae, can be differentiated from the allied D. doederleini by its different carapace form,
structures of the antennal basis and features of the female thoracic sterna.
KEY WORDS. – Dicranodromia martini, Dicranodromia chenae, new species, Homolodromiidae, Philippines,
taxonomy.

INTRODUCTION

terminology follows that used by Guinot (1995). The
abbreviations P2–P5 are used for the pereiopods 2–5,
respectively.

The family Homolodromiidae currently contains two generaand 22 species from the Indo-West Pacific and the Atlantic(Guinot, 1995; Martin et al., 2001; Ng & McLay, 2005). From
the Philippines, two homolodromiid species have beenrecorded to date: Dicranodromia martini Guinot, 1995 (fromthe Sulu Sea, 930 m and north of Mindanao Island, 750 m)
and D. danielae Ng & McLay, 2005 (Balicasag Island,
Panglao, 200–300 m). During the PANGLAO 2005 deepsea expedition conducted in the Bohol and Sulu Seas in theCentral Philippines, two more homolodromiids wereobtained: Dicranodromia martini and D. chenae, new species.
The present study report describes the new species as well
as discusses the morphological variation observed in D.
martini.

TAXONOMYHOMOLODROMIIDAE
Dicranodromia A. Milne Edwards, 1880
Remarks. – The genus Dicranodromia now contains 17
species, nine of which occur in the Indo-West Pacific (Guinot,
1995; Ng & McLay, 2005). Most species are represented byonly few specimens, so it is not easy to ascertain variation,
sexual differences and changes that may be due to relative
growth. Even with the best known species, D. doederleini
Ortmann, 1892, there are a number of problems with assessing
the significance of the variation observed (see Guinot, 1995:
206–207).

Specimens are deposited in the National Museum of thePhilippines, Manila (NMCR); and the Zoological ReferenceCollection of the Raffles Museum of Biodiversity Research,
National University of Singapore (ZRC). Carapace length(CL) is measured from the tip of the pseudo-rostrum to theposterior margin of the carapace and carapace width (CW)
is measured across the greatest width. G1 and G2 are used
for the male first and second gonopods, respectively. The

Comparative material. – Dicranodromia danielae Ng &McLay, 2005: 1 ovigerous female, holotype (CL 14.2 mm,
CW 10.8 mm) (ZRC 2005.0094), Balicasag Island, Panglao,
Bohol, Visayas, the Philippines, in tangle nets, ca. 200–300

47

Ng & Naruse: Homolodromiidae from the Philippines
Remarks. – Three specimens recently collected by the
Panglao Expeditions agree well with the description of
Dicranodromia martini Guinot, 1995. Guinot (1995: 223)
stated that the dactyli of P2 and P3 are as long as the carpi,
but our specimens show minor variation in this character.
The largest specimen (a female, ZRC 2007.0106, CL 34.2mm, Fig. 1a), has the P2 and P3 dactyli slightly shorter thanthe carpi, whereas those of the medium-sized specimen (amale, ZRC 2007.0105, CL 16.6 mm, Fig. 1b, c) are as longas the carpi, and those of the smallest specimen (a female,
NMCR 19114, CL 12.8 mm, Fig. 1d) are slightly longer thanthe carpi. Guinot’s (1995: Fig. 20C) figure of the P2 of asmall specimen (U.S. Museum of Natural History,
Washington DC, USNM 128563, CL 13 mm) also has thedactylus slightly longer than the carpus.

m, coll. local shell fishermen, 2 Mar.2004. Homolodromia
paradoxa (A. Milne Edwards, 1880): 1 male (CL 31.9 mm,
CW 23.4 mm) (ZRC 1999.0047), off Suriname, 7°48'N
54°11'W, coll. Mar. Res. Stn., 22 Apr.1980. Homolodromia
kai Guinot, 1993: 1 ovigerous female (CL 34.3 mm, CW 26.4mm) (ZRC 1999.0040), Tungsha Islands, 650 m depth, coll.
P.-H. Ho, 22 Apr.1995; 1 male (CL 26.5 mm, CW 20.2 mm)(ZRC 2007.0103), southwest of Kaohsiung, Taiwan, station
CD141, 277–355m, 22°21.64'N 120°13.44'E, 24 Nov.2001;
1 male (CL 13.7 mm, CW 9.9 mm) (ZRC 2007.0104),
southwest of Kaohsiung, Taiwan, station CP130, 709–728m,
22°18.77'N 120°6.99'E, 22 Aug.2001.

Dicranodromia martini Guinot, 1995
(Figs. 1, 3a, b, 4)

The male (ZRC 2007.0105) and the smaller female specimen(NMCR 19114) both have a movable spine on the extensor
margin of the dactylus of the P5 (Fig. 3a), but this spine iscompletely absent on the larger female specimen (ZRC
2007.0106, CL 34.2 mm) (Fig. 3b). This character was figured
for D. felderi Martin, 1990, by Martin (1990: Fig. 3d) andGuinot (1995: Fig. 3H), and D. spinosa Martin, 1994, by
Martin (1994: Fig. 2f). The spine might be missed in many

Material examined. – 1 male (CL 16.6 mm, CW 12.3 mm) (ZRC
2007.0105), Maribohoc Bay, Panglao, Bohol, station CP 2396, 609–
673 m, 9°36.3'N 123°42.0'E, 31 May 2005; 1 female (CL 34.2 mm,
CW 28.1 mm) (ZRC 2007.0106), Bohol and Sulu Seas, station CP
2363, 437–439 m, 9°06.0'N 123°25.0'E, 26 May 2005; 1 female(CL 12.8 mm, CW 9.6 mm) (NMCR 19114), Bohol Sea, station CP
2388, 762–786 m, 9°26.9'N 123°34.5'E, 30 May 2005. All from thePhilippines, coll. MV DA-BFAR, PANGLAO 2005 Expedition.

Fig. 1. Dicranodromia martini Guinot, 1995: a, female (CL 34.2 mm, CW 28.1 mm) (ZRC 2007.0106); b, c, male (CL 16.6 mm, CW 12.3mm) (ZRC 2007.0105); d, female (CL 12.8 mm, CW 9.6 mm) (NMCR 19114). a–c, colours in life.

48

THE RAFFLES BULLETIN OF ZOOLOGY 2007
Dicranodromia chenae, new species(Figs. 2, 5–8)

species as the many setae on the dactylus make it difficult toobserve and it can easily be missed. Indeed, a re-examinationof the holotype of D. danielae Ng & McLay, 2005, reveals
the presence of such a spine as well (Fig. 4c) although Ng& McLay (2005: Fig. 4B) did not figure it. Examination of
specimens of Homolodromia paradoxa (A. Milne Edwards,
1880) and H. kai Guinot, 1993, as well as a careful check of
the references for other Homolodromia species, reveals thatthey all lack the spine (cf. H. bouvieri Doflein, 1904: Martin,
1992: Fig. 2G; Guinot, 1995: Fig. 3D; H. robertsi Garth, 1973:
Garth, 1973: Fig. 1A; Baéz & Martin, 1989: Fig. 2f; H.
monstrosa Martin, Christiansen & Trautwein, 2001: Martin
et al., 2001: Fig. 5e). Careful examination of more material
will be needed to ascertain the importance of this characterat the generic and specific levels. This character has beenused in the taxonomy of the family Dromiidae and its
evolution discussed (see McLay, 1993).

Material examined. – Holotype: female (CL 30.5 mm, CW 22.7mm) (NMCR 19115), Bohol Sea, station CP 2343, 273–356 m,
9°27.4'N 123°49.4'E, the Philippines, coll. MV DA-BFAR,PANGLAO 2005 Expedition, 23 May 2005.

Description. – Carapace sub-trapezoidal, widest acrossintestinal-mesobranchial regions, CL 1.34 times CW; dorsal
surface convex, surface sparsely granulated around margins,covered by dense, stiff setae; setae also present on pereiopods,
thoracic sternum and abdomen. Branchial-cardiac groove
distinct, curving medially anteriorly; cervical groove
shallower but still discernible. Pseudo-rostrum bifurcate, eachlobe triangular, sloping inwards, slightly incurving distally,
tapering tip terminated by sharp tooth; external orbital toothwith relatively broad base, oriented anterolaterally, but distal
part abruptly narrowing, directed more anteriorly, anterior
margin with 1 or 2 small teeth; supraorbital margin separated
from external orbital tooth by triangular cleft, outer part witha few small teeth; infraorbital margin present only on outer
half, bifurcated, outer lobe much larger, reaching half lengthof pseudo-rostrum in dorsal view. Subhepatic region produced
anteriorly, epistome with small spinules, posterior margin
upturned, with median fissure. Antennae well-developed, withlong flagellum; basis with strong, circular conical lateralexternal projection as long as antennal basis, with a spinuleon distal end. Eyes with long peduncle, distal part with small
teeth, cornea placed between lateral external projection ofantennal basis and outer lobe of infraorbital tooth in dorsal
view. Third maxilliped narrow, sloping dorsally from inner
to outer part; ischium relatively wide distally, longer thanmerus; merus sloping dorsally from subproximal outer todistal inward; palp (carpus, propodus, dactylus) relatively
long, reaching beyond distal inner angle of ischium by half
length of dactylus; exopod with slightly subdistal part

The largest female specimen (ZRC 2007.0106) also possesses
a more inflated posterolateral margin of the carapace and amore anteriorly directed external orbital tooth (Fig. 1a). We,
however, hesitate to consider these differences asinterspecific, as only one specimen is available. Considering
the limited number of specimens of D. martini known andthe significant differences in sizes of the material on hand,
we prefer to provisionally treat all three specimens as D.
martini.
The only male specimen (ZRC 2007.0105, CL 16.6 mm)already possesses a well developed G1 and G2 (Fig. 4) andthe species appears to be mature at this size. The G1 is alreadychitinised, and the distal segment is slightly directed inwards
with a ventral side of an outer layer marginally covering an
inner layer to form a groove for the G2. The G2 is long, withthe distal segment longer than the distal two segments of theG1 and is slightly sinuous along half its length.

Fig. 2. Dicranodromia chenae, new species. Holotype female (CL 30.5 mm, CW 22.7 mm) (NMCR 19115): Colours in life (a, b) andcarrying sponge (b).

49

Ng & Naruse: Homolodromiidae from the Philippines
concave, widest on proximal third, slightly wider than half
width of ischium.

dactylus with length about two-thirds of carpus, terminatingin strongly incurving claw, flexor margin lined equidistantlywith 6–8 teeth; P4 stouter, shorter than P5; P5 with thin, longspine on distal part of dorsal outer angle of carpus andproximal fourth of outer surface of propodus; distal end of
propodus not produced, sharp spines fringing distal margin
except for inner surface of base of dactylus; dactylus clawlike, strongly incurving, dactylus of P5 with a movable spine
on proximal third of extensor margin.

Chelipeds (P1) almost symmetrical, densely covered with stiff
setae on most parts; merus with both outer lower and innerlower margins sparsely lined with small teeth; palm withslightly convex outer surface, upper half with scattered
granules; inner surface with scattered rounded tubercles on
upper half, longitudinal shallow ridge on upper third,
relatively less setose below ridge; movable finger thick,occluding surface hollowed, distal half gently swollen
laterally, curving distally downwards, upper outer part withcleft through medial third, setae covering upper dorsal partto below cleft; immovable finger with distal deep U-shaped
depression, into which tip of movable finger fits when chela
closed; outer upper margin with 1 basal triangular tooth,
followed by a few small and 4 or 5 anteriorly directed lobelike teeth, setae present only proximally to middle of outersurface, inner upper margins concave on proximal half. P2
and P3 relatively short, P3 longer than P2; meri without
conspicuous tooth on posterior margins; propodi almost
straight, with 1 movable yellow spine on distal inner angle;

Thoracic sternite 7 with short, anteriorly-convex transverse
ridge from posterior inner part of sexual opening, with oblique
ridge from posterior to transverse ridge to just anterior to innerend of suture between thoracic sternites 7 and 8, posterior
end of oblique ridge partially covering spermathecal aperture;
aperture placed posterior to a line joining posterior marginof P3 coxae.
Abdomen with 6 free segments and telson; segments relatively
short; telson long, as long as combined length of first to fifth
abdominal segments.

Fig. 3. Dactylus of P5 of Dicranodromia species: a, D. martini Guinot, 1995, male (CL 16.6 mm, CW 12.3 mm) (ZRC 2007.0105); b, D.
martini Guinot, 1995, female (CL 34.2 mm, CW 28.1 mm) (ZRC 2007.0106); c, D. danielae Ng & McLay, 2005, holotype ovigerous female(CL 14.2 mm, CW 10.8 mm) (holotype, ZRC 2005.0094). Scale bars = 1.0 mm. Arrows indicate the movable spine of the extensor marginof the dactylus.

50

THE RAFFLES BULLETIN OF ZOOLOGY 2007

Fig. 4. G1 and G2 of Dicranodromia martini Guinot, 1995. Male (CL 16.6 mm, CW 12.3 mm) (ZRC 2007.0105): a, left G1, ventral view;b, distal part of left G1, dorsal view; c, distal part of left G1, inner view; d, left G2, ventral view. Scale bars = 1.0 mm.

51

Ng & Naruse: Homolodromiidae from the Philippines
Etymology. – The species is named in honour of the late Chen
Huilian, a good friend and renowned Chinese carcinologist,
who unfortunately passed away just before Christmas 2006.
Remarks. – Dicranodromia chenae, new species, is distinct
from all known Indo-West Pacific species by the inwardsloping pseudo-rostrum and the external orbital tooth with awide base and sinuous anterior-inner margin. Dicranodromia
chenae can be separated from D. doederleini Ortmann, 1892,
by moderately short pereiopods and less granulated outersurface of the palm of the cheliped. Additional characters of
D. chenae, differentiating it from D. doederleini, are the long

Fig. 5. Anterior part of cephalothorax of Dicranodromia chenae,
new species. Holotype female (CL 30.5 mm, CW 22.7 mm) (NMCR
19115): a, dorsal view; b, ventral view.

Fig. 7. Outer view of P5 dactylus of Dicranodromia chenae, newspecies. Holotype female (CL 30.5 mm, CW 22.7 mm) (NMCR
19115). Scale bar = 1.0 mm. Arrow indicates the movable spine of
the extensor margin of the dactylus.

Fig. 6. Right chela, P4 and P5 of Dicranodromia chenae, newspecies. Holotype female (CL 30.5 mm, CW 22.7 mm) (NMCR
19115): a, outer view; b, inner view; c, lower view; d, upper view;p4, pereiopod 4, outer view; p5, pereiopod 5, outer view. Arrow
indicates the movable spine of the extensor margin of the dactylus.

Fig. 8. Thoracic sternum of Dicranodromia chenae, new species.
Holotype female (CL 30.5 mm, CW 22.7 mm) (NMCR 19115): 7,
8 = thoracic sternite 7 and 8; g = gonopore; p3–5 = P3–P5; s =spermathecal aperture.

52

THE RAFFLES BULLETIN OF ZOOLOGY 2007
distal outer projection of the antennal basis (as long asantennal basis vs. distinctly shorter than antennal basis), theabsence of a true rostrum (vs. present in D. doederleini), andthe relative position of the spermathecal aperture and thepresence of an anterior eave (spermathecal aperture placed
posterior to a line joining posterior margin of coxae of P3 vs.
placed anterior to the line, without anterior eave).

Doflein, F., 1904. Brachyura. Wissenschaften Ergebnisse, deutschen
Tiefsee-Exped. “Valdivia”, 6: i–xiv, 1–314, Figs. 1–68, Pls. 1–
58, 1 map.
Garth, J. S., 1973. New taxa of brachyuran crabs from deep-waters
off Western Peru and Costa Rica. Bulletin of the South California
Academy of Science, 72(1): 1–12, Figs. 1–5.
Guinot, D., 1993. Données nouvelles sur les crabes primitifs(Crustacea Decapoda Brachyura Podotremata). Comptes rendus
de l’Académie des Sciences (III), 316(10): 1225–1232, Figs. 1–
8.

Two species of Dicranodromia, D. martini Guinot, 1995, andD. danielae Ng & McLay, 2005, have been recorded fromthe Philippines thus far. Dicranodromia martini and D.
danielae share a similar shape of the extra-orbital tooth, which
is not found in D. chenae. Furthermore, D. martini can be
distinguished from D. chenae by its longer pereiopods andgreater coverage of setae on the chela, and D. danielae canbe differentiated from D. chenae by the arrangement of thespines on the outer surface of the P5 propodus and straight
posterior margin of the epistome.

Guinot, D., 1995. Crustacea Decapoda Brachyura: Révision de lafamille des Homolodromiidae Alcock, 1900. In: Crosnier, A.
(ed.), Résultats des Campagnes MUSORSTOM. Volume 13,
Mémoires du Muséum national d’Histoire naturelle, 163: 155–
282.
Ho, P.-H. & P. K. L. Ng, 1999. On a Homolodromia kai Guinot,
1993 (Decapoda, Brachyura, Homolodromiidae) from the South
China Sea. Crustaceana, 72(9): 1123–1126.
Ikeda, H., 1998. The deep-sea crabs of Sagami Bay. Hayama Shiosai
Museum. 180 pp. (in Japanese).

Ikeda (1998: 20, Pl. 1 Fig. 3) was probably the first author
to record the carrying behaviour for camouflage ofhomolodromiid crabs; he mentioned that D. doederleini often
carried a glass sponge. Ho & Ng (1999) subsequently reported
a sponge-carrying Homolodromia kai Guinot, 1993, from
Taiwan, although the kind of sponge was not identified. Whenthe holotype of D. chenae was collected, it was still alive
and carrying a glass sponge (Fig. 2b). The sponge fitted overthe entire carapace surface and is carried in the same way as
in dromiids. This is only the third observation of sponge
carrying behaviour in homolodromiid crabs.

Martin, J. W., 1990. Crabs of the family Homolodromiidae, II.
Dicranodromia felderi, new species, from the western Atlantic,
with notes on the type series of D. ovata A. Milne Edwards,
1880. Journal of Crustacean Biology, 10(4): 708–720.
Martin, J. W., 1992. Crabs of the family Homolodromiidae, IV.
Rediscovery and redescription of Homolodromia bouvieri
Doflein, 1904 (Decapoda: Dromiacea) from off Mozambique.
Journal of Crustacean Biology, 12: 145–150.
Martin, J. W., 1994. Crabs of the family Homolodromiidae(Crustacea, Decapoda, Brachyura), V. Dicranodromia spinosa,
a new species from the western Atlantic. Proceedings of the
Biological Society of Washington, 107(3): 451–457.

ACKNOWLEDGEMENTS

Martin, J. W., J. C. Christiansen & S. E. Trautwein, 2001. Crabs of
the family Homolodromiidae, VI. Homolodromia monstrosanew species (Decapoda: Brachyura) from the western northAtlantic with a redescription of the holotype of Homolodromia
paradoxa A. Milne Edwards, 1880 and comments on sexual
dimorphism. Bulletin of Marine Science, 68(2): 313–326.

The specimen was collected during the Philippine-FrenchSingapore Deep Sea Expedition, Panglao 2005, to the Bohol
and Sulu Seas, and we thank the organisers, Philippe Bouchet(Muséum national d’Histoire naturelle, Paris, MNHN), Danilo
Largo (University of San Carlos, Cebu) and Luduvina Labe
(Bureau of Fisheries of the Philippines, Manila) for their kind
help and support. We acknowledge the financial support of
TOTAL Foundation, ASEAN Regional Centre for
Biodiversity and Conservation (ARCBC) (Manila), MNHN;
and the Faculty of Science, National University of Singapore.
We thank Bertrand Richer de Forges (Institut de Recherche
pour le Développement, Nouméa, New Caledonia), Tan Swee
Hee, Joelle Lai (ZRC), Marivene Manuel-Santos (NMCR),
as well as Chan Tin Yam and Lee Chia-Wei (National Ocean
University, Keelung, Taiwan) for their help during the cruise.
Chan Tin Yam, kindly photographed the fresh specimens
during the cruise. We also thank two anonymous reviewersof the manuscript for their useful comments.

McLay, C., 1993. Crustacea Decapoda: the sponge crabs(Dromiidae) of New Caledonia and the Philippines with a reviewof the genera. In: Crosnier, A. (ed.), Résultats des Campagnes
MUSORSTOM. Volume 10, Mémoires du Muséum nationald’Histoire naturelle, 156: 111–251.
Milne-Edwards, A., 1880. Etudes préliminaires sur les Crustacés,1ère Partie. Reports on the results of dredging under thesupervision of Alexander Agassiz, in the Gulf of Mexico, andin the Caribbean Sea, 1877, ’78, ’79, by the U. S. Coast Survey
Steamer «Blake», Lieut.-Commander C. D. Sigsbee, U. S. N.,
and Commander J. R. Bartlett, U. S. N., Commanding, VIII.
Bulletin of the Museum of Comparative Zoology, Harvard
University, 8(1): 1–68, Pls. 1, 2.
Ng, P. K. L. & C. L. McLay, 2005. Dicranodromia danielae, a new
species of homolodromiid crab from the Philippines (Crustacea:
Decapoda: Brachyura). Zootaxa, 1029: 39–46.
Ortmann, A. E., 1892. Die Decapoden-Krebse des Strassburger
Museums, mit besonderer Berücksichtigung der von Herrn Dr.
Döderlein bei Japan und bei den Liu-Kiu-Inseln gesammelten
und z.Z. im Strassburger Museum aufbewahrten Formen. V.
Theil. Die Abtheilungen Hippidea, Dromiidea und Oxystomata.
Zoologische Jahrbücher, Abtheilung für Systematik, Geographie
und Biologie der Thiere, 6: 532–588, Pl. 26.

LITERATURE CITED
Baéz R., Pedro & J. W. Martin, 1989. Crabs of the family
Homolodromiidae, I. Description of the male of Homolodromia
robertsi Garth, 1973, based on specimens from deep waters off
the coast of Chile. Journal of Crustacean Biology, 9(3): 492–500.

53