Gigantione tau, An & Yu & Markham, 2009

An, Jianmei, Yu, Haiyan & Markham, John C., 2009, First record of the genus Gigantione (Epicaridea: Bopyridae: Pseudioninae) from Chinese waters, with description of three new species, Journal of Natural History 43 (5 - 6), pp. 335-353 : 346-352

publication ID	https://doi.org/ 10.1080/00222930802590737
persistent identifier	https://treatment.plazi.org/id/03D9CC30-FFD7-BE1E-FE6E-C3D830014382
treatment provided by	Felipe
scientific name	Gigantione tau
status	sp. nov.

Treatment

Gigantione tau View in CoL sp. nov.

( Figures 7 View Figure 7 , 8 View Figure 8 )

Material examined

Infesting Carcinoplax longimanus (De Haan) . Determination of host, Huiliang Chen. Holotype: East China Sea, Stn 4076, 28 ° 30 9 N, 124 ° 00 9 E, 91 m, 22 October 1959, Coll. Guangyu Lin, 1♀, CIEG407601 GoogleMaps . Allotype: East China Sea, Stn 4076, 28 ° 30 9 N, 124 ° 00 9 E, 91 m, 22 October 1959, Coll. Guangyu Lin, 1 „, CIEG407602 GoogleMaps . Paratypes: East China Sea, Stn 4065, 29 ° 00 9 N, 123 ° 30 9 E, 78 m, 9 July 1959, Coll. Liren Chen, 1♀ (immature), CIEG406501 GoogleMaps .

Description of holotype (CIEG407601)

Length 6.92 mm, maximal width 6.73 mm, head length 1.96 mm, head width 2.53 mm, pleon length 1.58 mm, distortion 30 ° dextrally ( Figure 7A View Figure 7 ).

Head subtriangular, wider than long, posterior margin slightly bilobate, frontal lamina absent. ‘‘T’’-shaped pigmentation on dorsal surface. Anterolateral flaps projecting on each side of head. Eyes absent ( Figure 7A View Figure 7 ). First antenna of two articles, second antenna of five articles, slightly setose terminally ( Figure 7C View Figure 7 ). Maxilliped suboval, palpless, its anterior article five times larger than posterior one and marginally fringed by dense setae ( Figure 7D View Figure 7 ). Barbula with one pair of prominent falcate lateral projections on each side, four to five small projections almost completely encircled by lateral projections, pair of small projections in centre ( Figure 7E View Figure 7 ).

Pereon broadest across fourth pereomere, second pereomere to fourth pereomere fused in the middle region ( Figure 7A View Figure 7 ). Coxal plates well-developed on both sides of all pereomeres, their margins slightly dentate. Coxal plates on long sides with prominent tubercles, but those on short sides obscure. First four pereomeres with round dorsolateral bosses, those on long sides larger than those opposite. Oostegites incompletely enclosing brood pouch ( Figure 7B View Figure 7 ). First oostegite ( Figure 7F,G View Figure 7 ) with wide and deep groove separating it into two articles; internal ridge bearing five to six projections, posterolateral point blunt and round. All pereopods of about same size ( Figure 5H,I View Figure 5 ), each basis produced into prominent lobe along flexor margin.

Pleon of six pleomeres, first five bearing biramous pleopods and lateral plates, terminal segments not reaching general body outline; only short uropods visible in dorsal view. Lateral plates on long sides tuberculate and much longer, but those on opposite sides smooth and very short ( Figure 7A View Figure 7 ). Pleopods of first pair ( Figure 7J View Figure 7 ) larger than other pereopods, with lamellar, tuberculate, dentate margins. Exopodites of second pleopods similar to those of the first pleopods ( Figure 7K View Figure 7 ), but endopodites much smaller and with slender digitate tubercles. Third and fourth pleopods similar ( Figure 7L,M View Figure 7 ), all with slender digitate tubercles. Fifth pleopod almost smooth, two to three small tubercles only on exopodite. Biramous uropods much smaller than pleopods.

Description of allotype (CIEG407602)

Length 3.54 mm, maximal width, across pleomere 5, 1.42 mm, head length 0.39 mm, head width 0.97 mm, pleonal length 1.35 mm. All body regions and segments distinctly separated ( Figure 8A,B View Figure 8 ).

Head semicircular, yellow eyes near posterior margin of head ( Figure 8A View Figure 8 ). Antenna of three articles, with setae on basal two articles; antennule of five articles, with setae on basal article ( Figure 8C View Figure 8 ).

Pereon with round margins, without midventral projections ( Figure 8B View Figure 8 ). First pereopods much larger than others, all of similar structure ( Figure 8D,E View Figure 8 ).

Pleon of six pleomeres, without midventral projections ( Figure 8B View Figure 8 ). Five pairs of rod-like uniramous pleopods, Sixth pleomere produced into uniramous uropods ( Figure 8B View Figure 8 ).

Descriptive notes on immature female (CIEG406501)

Head polygonal, ‘‘T’’-shaped pigmentation obscure, without eyes ( Figure 8F View Figure 8 ). Antennules extending beyond margin of head and visible in dorsal view. Second to fourth pereomeres constricted medially. All pereomeres and pleomeres with conspicuous dentate coxal plates. Brood pouch flat and completely closed ( Figure 8G View Figure 8 ).

Etymology

The species name is the Greek letter tau selected in reference to the ‘‘T’’-shaped pigmentation on the head of the holotype female and used as a noun in apposition.

Remarks

The female of the new species, G. tau , is distinguished from the other 13 species of the genus by having dentate coxal plates with prominent tubercles on the long sides and a unique ‘‘T’’-shaped pigmentation on the surface of head. Gigantione tau appears to be most closely related to G. rhombos , described above, which also infests goneplacid crabs. The female of G. tau differs from that of G. rhombos in that its coxal plates bear prominent tubercles only on their long sides, by its ‘‘T’’-shaped head pigmentation, and by its barbula having a pair of central projections. The female of G. rhombos is almost symmetrical, it has distinct dentate coxal plates with small tubercles on each side, it lacks pigmentation, and its barbula has a prominent central rhombic projection.

Distribution and hosts

East Sea, China, infesting Carcinoplax longimanus (De Haan) .

Species of Brachyura known to bear bopyrid parasites in Chinese waters, their parasites and localities, with authorities for Chinese records

Infraorder BRACHYURA

Section EUBRACHYURA

Superfamily LEUCOSIOIDEA

Family LEUCOSIIDAE

Leucosia anatum (Herbst) : Apocepon leucosiae An, Yu and Li, 2006 ; South China Sea ( An et al. 2006b).

L. longibranchia Shen and Chen : Onkokepon articulatus An, Yu and Li, 2006 View in CoL ; Beibu Gulf ( An et al. 2006a) and Onkokepon beibuensis An, Yu and Li, 2006 View in CoL . Beibu Gulf ( An et al. 2006a).

L. sinica Shen and Chen View in CoL : Apocepon digitatum Stock, 1960 View in CoL ; South China Sea ( An et al. 2006b).

L. unidentata De Haan : Onkokepon articulatus An, Yu and Li, 2006 ; Beibu Gulf ( An et al. 2006a).

Philyra carinata Bell : Apocepon pulcher Nierstrasz and Brender View in CoL à Brandis, 1930; Zhejiang Province ( Huang 1994), Qingdao and Shandong Provinces ( An et al. 2006b).