Megacepon sheni, An & Boyko & Li, 2011
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publication ID |
https://doi.org/ 10.1080/00222933.2011.626128 |
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DOI |
https://doi.org/10.5281/zenodo.10536863 |
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persistent identifier |
https://treatment.plazi.org/id/03E60416-FC30-FFF1-FE25-E0FCFE5AFCD3 |
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treatment provided by |
Felipe |
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scientific name |
Megacepon sheni |
| status |
sp. nov. |
Megacepon sheni View in CoL sp. nov.
( Figures 1 View Figure 1 , 2 View Figure 2 )
Material examined
Infesting Metaplax sheni Gordon, 1931 ( Figure 1 View Figure 1 ), Qiongshan , Hainan Province, 20 ◦ 00 ′ N, 110 ◦ 30 ′ E, 7 June 1958, coll. Ruiyu Liu, holotype female ( CIEG580601 ), allotype male ( CIEG580602 ) GoogleMaps .
Description of holotype
Length (excluding uropods) 4.68 mm, maximum width across pereomere 4, 2.96 mm, head length 1.30 mm, head width 1.32 mm, pereon length 2.13 mm, pleon length 1.25 mm, sinistral distortion 40 ◦. Pereomeres distinct, but separation of pleomeres obscure. No pigmentation ( Figure 2A, B View Figure 2 ).
Head expanded and rounded anteriorly, tapered anteriorly, with well-developed frontal lamina, extending anterolaterally. Eyes absent ( Figure 2A View Figure 2 ). Antenna of three articles, terminal one setose, antennule lacking ( Figure 2C View Figure 2 ). Maxilliped bearing stout, triangular non-articulating palp extending prominently forward, lacking setae; plectron short and sharply tapered ( Figure 2D View Figure 2 ). Barbula ( Figure 2E View Figure 2 ) with two prominent pointed falcate lateral projections on each side, outer one distinctly larger than inner; large tubercle medial to inner falcate projection and broad shorter tubercle medial to those.
Pereon broadest across pereomere 4, gradually tapering anteriorly and posteriorly. Coxal plates absent. Pereomeres 3–5 with small mid-dorsal projections, pereomere 6 with prominent mid-dorsal projection, pereomere 7 recessed under pereomere 6, lacking projection. Dorsolateral bosses on pereomeres 1–4, and tergal projections only on left side of pereomeres 2–4 ( Figure 2A View Figure 2 ). Oostegites completely enclosing highly vaulted brood pouch ( Figure 2B View Figure 2 ). First oostegite ( Figure 2F, G View Figure 2 ) with ovate anterior segment and elongate subquadrate posterior segment, anterior segment smoothly rounded anteriorly, with slightly digitate internal ridge bearing five short lobes of various widths, posterior segment expanded at mid-length of lateral margin, tapering to rounded posterior tip. Last pair of oostegites smooth, lacking tubercles. Pereopods subequal, with all articles distinct and each article of nearly same size on all pereopods; all dactyli small and blunt ( Figure 2H, I View Figure 2 ).
Pleomere 1 distinct with prominent narrow triangular mid-dorsal projection, pleomeres 2–5 apparently fused into one piece without any projections. Five pairs of biramous pleopods and lateral plates. Lateral plates, exopodites and endopodites of similar size and structure, with surfaces tuberculate and margins highly digitate ( Figure 2J View Figure 2 ). Uniramous uropods similar to structure of pleopods and lateral plates but shorter than lateral plates of pleomere 5.
Description of allotype male
Length 2.31 mm, maximal width across pleon 3, 0.46 mm, head length 0.16 mm, head width 0.25 mm, pleonal length 0.51 mm. All body segments distinct ( Figure 2K, L View Figure 2 ).
Head semicircular, eyes lacking ( Figure 2K View Figure 2 ). Antenna of three articles, distal ones setose; antennule of five articles, extending beyond the margin of head ( Figure 2M View Figure 2 ).
Pereomeres near subequal in width, with truncate margins. All pereomeres with prominent mid-ventral tubercles ( Figure 2L View Figure 2 ). Pereopods subequal in size, all articles distinct ( Figure 2N, O View Figure 2 )
Pleon of six pleomeres, first three with mid-ventral tubercles ( Figure 2L View Figure 2 ). Five pairs of uniramous tuberculiform pleopods, progressively smaller posteriorly. Pleomere 6 bearing uniramous lobes similar in structure and placement to pleopods ( Figure 2L View Figure 2 ).
Etymology
The specific name sheni is selected to honour Prof. Jia-rui Shen (1902–75), for his contributions to the research of Crustacea in China. It is also the species name of the host crab.
Distribution and hosts
Hainan province, China, infesting Metaplax sheni Gordon, 1931 .
Remarks
The lack of antennules on the holotype may not be a species character but rather specific to this specimen. Lack of antennules, or even both antennae and antennules, has been reported in other bopyrids (e.g. Markham 2010: 168) but has never been used to distinguish species within the genus Megacepon . This species is most similar to Megacepon aff. goetici sensu Bourdon and Stock (1979 , not M. goetici sensu stricto, see below) as well as to Megacepon disparatum sp. nov., described below. All three of these taxa have males with short pleotelson anterolateral projections and females with two long falcate projections on the lateral margins of the barbula. Megacepon sheni sp. nov. can be distinguished from M. aff. goetici by absence of medial boss on pereomere 5 of the female (present in M. aff. goetici ), differently shaped oostegite 1 (inner mediolateral projection of anterior segment not tapered in M. sheni , digitations on ridge much smaller in M. sheni ), and male with only three mid-ventral pleonal tubercles ( M. aff. goetici with five tubercles). This new species can be distinguished from M. disparatum by the shape of the medial boss on pereomere 6 of the female (unilobed in M. sheni , bilobed in M. disparatum ), oostegite 1 differently shaped (mediolateral projection of posterior segment projected in M. sheni , not projected in M. disparatum ; nearly right angled notch near distal end of posterior segment in M. disparatum , lacking in M. sheni ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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