First Record of a Hyalid Species, Protohyale pumila (Crustacea: Amphipoda: Hyalidae), from Korea

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  • ABSTRACT

    A hyalid amphipod, Protohyale pumila (Hiwatari and Kajihara, 1981), collected from Jeju Island is reported for the first time in the Korean fauna. The species is characterized by the presence of a short apical spine on the palp article 4 of maxilliped, a distinctly large and blunt cusp on the propodus of male gnathopod 1, and a distal truncate process on the palm of male gnathopod 2. Herein, the present species is described and illustrated. Korean hyalid amphipods now are composed of four species belonging to three genera. Voucher specimens were deposited in the Marine Arthropod Depository Bank of Korea, Seoul National University.


  • KEYWORD

    Protohyale pumila , Hyalidae , Amphipoda , marine , Korea

  • INTRODUCTION

    Members of the family Hyalidae are part of the littoral marine amphipod group and mainly inhabit intertidal zones and shallow water. Most members of the group are found among algae living in warmer waters (Barnard and Karaman, 1991; Hiwatari, 2003). A few subgroups of the hyalid amphipods, including the genus Protohyale Bousfield and Hendrycks, 2002, are known for having a simple-form preamplexing notch of peraeon segment 2 in female. The dactylus of male gnathopod 1 meshes correctly with and is used to grasp the precopularoty notch of the female (Hendrycks and Bousfield, 2001).

    Only one species, P. rubra (Thomson, 1879), has been found in Korea until now. In the present study, Protohyale pumila (Hiwatari and Kajihara, 1981) is reported for the first time as a member of the Korean amphipod fauna.

    Specimens were collected among algae living in the intertidal zone at Jeju Island, Korea and preserved in 95% ethanol. A stereomicroscope (MZ8; Leica, Wetzlar, Germany) and a compound microscope (BX-50; Olympus, Tokyo, Japan) were used for the observation. Dissection and mounting were conducted following the methodology of Barnard and Karaman (1991). Illustrations were made by using a drawing tube or camera lucida. Body length was measured from the tip of rostrum to the posterior end of urosomite 3. All specimens examined herein were deposited in the Marine Arthropod Depository Bank of Korea(MADBK, http://madbk.org) located at Seoul National University, Korea.

    SYSTEMATIC ACCOUNTS

    Order Amphipoda Latreille, 1816

    Family Hyalidae Bulycheva, 1957

    Genus Protohyale Bousfield and Hendrycks, 2002

    Key to the species of the genus Protohyale from Korea

    1. Propodus of gnathopod 1 in male and female dissimilar to each other; palm of male gnathopod 2 with distinct truncate process ?????????????????????????????????????????????????????????????????????????????????? P. pumila (Hiwatari and Kajihara, 1981)

    - Propodus of gnathopod 1 in male and female similar to each other; palm of male gnathopod 2 without process ?????????????????????????????????????????????? P. rubra (Thomson, 1879)

    1*Protohyale pumila (Hiwatari and Kajihara, 1981) (Figs. 1-3)

    Hyale dollfusi: Iwasa, 1939: 280, Pl. 18, text-fig. 18; Stephensen, 1944: 69, fig. 24 [not Chevreux, 1911].

    Hyale pumila Hiwatari and Kajihara, 1981: 35, figs. 1-4.

    Protohyale (Boreohyale) pumila: Bousfield and Hendrycks, 2002: 77, fig. 36.

    Material examined. Korea: 216♂♂, 21♀♀, Jeju-do, Jocheon- eup, Hamdeog-ri, Hamdeog Beach, 29 May 2007.

    Description. Male: Body (Fig. 1) 6.98 mm long, compressed. Lateral cephalic lobe slightly convex, anteroventral cephalic excavation shallow. Eye black, large. Terminal part of antenna 1 reaching about one-fourth portion of antenna 2 flagellum. Antenna 2 about 0.5 times as long as body length, peduncle 5 slightly longer than peduncle 4. Palp article 4 of maxilliped slightly broad, bearing short apical spine and short marginal setae.

    Coxa of gnathopod 1 (Fig. 2A) broad; basis without anterodistal lobe; carpus broad, bearing five spines on anterodistal margin, with expanded posterodistal lobe; propodus broadly expanded, anterior margin unarmed, with posterior marginal setae; palm convex, defined by large and blunt cusp, with one spine near defining corner; dactylus fitting palm.

    Coxa of gnathopod 2 (Fig. 2B) subquadrate; basis bearing anterodistal lobe; ischium with subcircular lobe; merus slightly extended; propodus very large, anterior margin convex; palm oblique, subequal as long as posterior margin, with distal truncate process having one spine and several setae, whole of palm bearing spines; dactylus fitting palm.

    Coxa of pereopod 2 (Figs. 2C, 3A) widest in middle, with posteroproximal excavation; propodus bearing pair of locking spines, locking spines subequal in size, heavily striated.

    Basis of pereopods 3-5 (Figs. 2D-F, 3B) broad, subcircular, weakly serrate on posterior margin; merus and carpus slender; propodus having pair of locking spines, proximal locking spine larger than distal one, locking spines weakly striated.

    Peduncle of uropod 1 (Fig. 3C) as long as rami, having large distolateral spine and marginal spines; inner and outer rami with three dorsal spines, respectively.

    Peduncle of uropod 2 (Fig. 3D) almost as long as rami, having marginal spines; inner and outer rami each with two dorsal spines.

    Peduncle of uropod 3 (Fig. 3E) about 1.5 times as long as ramus, bearing five inner marginal setae and two apicodorsal spines; ramus with six apical spines.

    Telson (Fig. 3F) completely cleft, both lobes having four small setae on lateral margin.

    Female: Body 6.12 mm long, slightly smaller than that of male.

    Basis of gnathopod 1 (Fig. 3G) weakly swollen anterodistally; propodus slender, subrectangular, middle part of posterior margin concave; palm oblique, simple; dactylus fitting palm.

    Gnathopod 2 (Fig. 3H) similar to gnathopod 1, rather lar-

    ger.

    Pereon segment 2 (Fig. 3I) bearing split-like preamplexing notch; posterior lobe strongly expanded forward, and overlapping with anterior lobe; without locking slit on surface.

    Distribution. Korea (Jeju Island), Japan.

    Remarks. Protohyale pumila (Hiwatari and Kajihara, 1981) is similar to P. laie (Barnard, 1970) and Hyale latimana Hiwatari, 2003. Each of the three species has a defining large and blunt cusp on the palm of male gnathopod 1, and one spine on the defining corner. However, the case of P. laie and H. latimana, the anterodistal margin of the propodus of male gnathopod 1 is tumid in shape, whereas that of P. pumila is not. In P. laie and H. latimana, there is no process on the palm of the male gnathopod 2, whereas there is a distinct truncate process in P. pumila. In P. laie, the palm of male gnathopod 2 is much longer than the posterior margin, whereas that of each of P. pumila and H. latimana is almost as long as the margin.

    The characteristics of our specimens coincide with those shown in Hiwatari and Kajihara’s original description based on specimens from Japan. Minor differences were observed in the shape of the carpus of gnathopod 1 and the ischium of gnathopod 2. The shape of male specimens was more rounded compared to that of the original description.

    Recently, the large genus Hyale in the family Hyalidae was revised by Bousfield and Hendrycks (2002) based on North Pacific fauna. They proposed five new genera from the genus Hyale. Now, six genera, Hyale Rathke, 1837, Apohyale Bousfield and Hendrycks, 2002, Protohyale Bousfield and Hendrycks, 2002, Ptilohyale Bousfield and Hendrycks, 2002, Ruffohyale Bousfield and Hendrycks, 2002, and Serejohyale Bousfield and Hendrycks, 2002, are valid (Serejo, 2004). Of these, the genus Protohyale was split into four subgenera: Boreohyale, Diplohyale, Leptohyale and Protohyale. In the revision by Bousfield and Hendrycks (2002), Hyale pumila was transferred as Protohyale (Boreohyale) pumila. However, Hughes and Lowry (2006) did not follow the subgeneric status of Bousfield and Hendrycks (2002), because the subgeneric taxonomy of Protohyale does not completely cover the Australian species. Therefore, they combined four subgenera into the genus Protohyale. In this study, we placed our species pumila in the genus Protohyale following the scheme of Hughes and Lowry.

    Korean name: 1*꼬마채찍해조숨이옆새우

  • 1. Barnard JL, Karaman GS 1991 The families and genera of marine gammaridean Amphipoda (except marine gammaroids). [Records of the Australian Museum, Supplement] Vol.13 P.1-866 google
  • 2. Bousfield EL, Hendrycks EA 2002 The talitroidean amphipod family Hyalidae revised, with emphasis on the North Pacific fauna: systematics and distributional ecology. [Amphipacifica] Vol.3 P.17-134 google
  • 3. Chevreux E 1911 Campagnes de la Melita. Les amphipodes d’algerie et de tunisie. I. gammarina. [Memoires de la Societe Zoologique de France] Vol.23 P.143-285 google
  • 4. Hendrycks EA, Bousfield EL 2001 The amphipod genus Allorchestes in the North Pacific region: systematics and distributional ecology. [Amphipacifica] Vol.3 P.3-37 google
  • 5. Hiwatari T 2003 Taxonomic studies on Hyale (Crustacea, Amphipoda, Hyalidae) from the coast of Japan and adjacent waters. [Publication of the Seto Marine Biological Laboratory] Vol.39 P.229-262 google
  • 6. Hiwatari T, Kajihara T 1981 Taxonomy of the family Hyalidae (Amphipoda, Crustacea) in Japan. II. A new species of the genus Hyale. [Proceedings of the Japanese Society of Systematic Zoology] Vol.21 P.35-40 google
  • 7. Hughes LE, Lowry JK 2006 New species of Amphipoda (Crustacea: Peracarida) from the Solitary Islands, New South Wales, Australia. [Zootaxa] Vol.1222 P.1-52 google
  • 8. Iwasa M 1939 Japanese Talitridae. Journal of the Faculty of Science Hokkaido Imperial University, Series VI [Zoology] Vol.6 P.255-296 google
  • 9. Serejo CS 2004 Cladistic revision of talitroidean amphipods (Crustacea, Gammaridea), with a proposal of a new classification. [Zoologica Scripta] Vol.33 P.551-586 google
  • 10. Stephensen K 1944 Some Japanese amphipods. [Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening] Vol.108 P.25-88 google
  • [Fig. 1.] Protohyale pumila (Hiwatari and Kajihara), male. Body. Scale bar=1 mm.
    Protohyale pumila (Hiwatari and Kajihara), male. Body. Scale bar=1 mm.
  • [Fig. 2.] Protohyale pumila (Hiwatari and Kajihara), male. A, Gnathopod 1; B, Gnathopod 2; C, Pereopod 2; D, Pereopod 3; E, Pereopod 4; F, Pereopod 5. Scale bars: A-F=0.5 mm.
    Protohyale pumila (Hiwatari and Kajihara), male. A, Gnathopod 1; B, Gnathopod 2; C, Pereopod 2; D, Pereopod 3; E, Pereopod 4; F, Pereopod 5. Scale bars: A-F=0.5 mm.
  • [Fig. 3.] Protohyale pumila (Hiwatari and Kajihara), male. A, Locking spines of pereopod 2 propodus; B, Locking spines of pereopod 5 propodus; C, Uropod 1; D, Uropod 2; E, Uropod 3; F, Telson. Female. G, Gnathopod 1; H, Gnathopod 2; I, Preamplexing notch of peraeon 2. Scale bars: A, B=0.05 mm, C, D, G, H=0.3 mm, E, F=0.1 mm, I=0.2 mm.
    Protohyale pumila (Hiwatari and Kajihara), male. A, Locking spines of pereopod 2 propodus; B, Locking spines of pereopod 5 propodus; C, Uropod 1; D, Uropod 2; E, Uropod 3; F, Telson. Female. G, Gnathopod 1; H, Gnathopod 2; I, Preamplexing notch of peraeon 2. Scale bars: A, B=0.05 mm, C, D, G, H=0.3 mm, E, F=0.1 mm, I=0.2 mm.