Cebudonus, Ng, Peter K. L., 2014
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publication ID |
https://doi.org/ 10.11646/zootaxa.3815.1.6 |
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publication LSID |
lsid:zoobank.org:pub:51A13505-C327-49F7-8FCC-0C407927C76C |
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DOI |
https://doi.org/10.5281/zenodo.6131210 |
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persistent identifier |
https://treatment.plazi.org/id/523B87B7-FF95-2706-06D6-224BFF6AD13E |
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treatment provided by |
Plazi |
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scientific name |
Cebudonus |
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gen. nov. |
Cebudonus View in CoL n. gen.
Type species. Cebudonus poppeorum n. gen., n. sp., by present designation.
Diagnosis. Carapace pentagonal; dorsal surface gently convex, covered with numerous small pits ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 ); front with 2 long pseudorostral spines, subparallel, ca. 0.4 times total carapace length, separated by broad U-shaped cleft ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 C); anterolateral margin entire, with large, broadly triangular, sharp lateral tooth, projecting laterally, dorsal surface gently convex ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 A, 4A); antennae with subrectangular basal article, twice as long as wide ( Fig. 3 View FIGURE 3 B); antennules folding at ca. 45° ( Fig. 3 View FIGURE 3 B); epistome relatively broad with depressed median part ( Fig. 3 View FIGURE 3 A–C); third maxilliped with ischium subrectangular, with deep submedian longitudinal sulcus ( Figs. 3 View FIGURE 3 C, 4A), merus subquadrate, anteroexternal angle subauriculiform ( Figs. 3 View FIGURE 3 C, 4A); ambulatory legs long, slender ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 E); ambulatory merus elongated, slender, surface with margins rounded, not cristate, not distinctly granular, dorsal distal tooth distinct but low ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 E); ambulatory propodus, dactylus with ventral margins lined with dense stiff setae, with distinct dactylo-propodal lock, not forming subchelate structure ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 D, E); cheliped merus rounded in cross-section; surface covered with numerous small pits ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 C); cheliped carpus surface with long, gently curved spine on distal inner angle ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 F); chela unarmed, margins not cristate ( Fig. 3 View FIGURE 3 F); thoracic sternum relatively narrow transversely, surfaces pitted, sternites 3, 4 completely fused with median depression ( Figs. 3 View FIGURE 3 C, 4B); male abdominal locking mechanism present as knob-like tubercle on distal one-third of thoracic sternite 5; male abdomen broadly triangular ( Figs. 3 View FIGURE 3 D, 4C); G1 slender, sinuous, distal part elongated ( Fig. 4 View FIGURE 4 F, G).
Etymology. The new genus is named after Cebu City in the Visayas, Philippines; in arbitrary combination with the genus name Eumedonus . The gender of the genus is masculine.
Remarks. The unusual combination of carapace, cheliped, ambulatory leg, thoracic sternal and abdominal characters in Cebudonus poppeorum n. gen., n. sp. require the establishment of a new genus. While the carapace shape of Cebudonus n. gen. superficially resembles species associated with echinoids like Eumedonus intermedius Chia & Ng, 2000 ( Madagascar) , E. vicinus Rathbun, 1918 ( Australia) , and E. zebra Alcock 1895 (Red Sea to East China Sea), especially with regard to the shape of the laterally directed spines; its front is completely different, with two long pseudorostral spines ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 ) in contrast to Eumedonus , which has a lobiform pseudorostrum that is bifurcated distally to form two teeth (cf. Chia & Ng 2000: figs. 8, 9A, D, 10, 11, 12A, D, N, 13, 14, 15A, D, Q, R). The lateral carapace tooth and the dorsal surface adjacent to it is gently convex dorsally in Cebudonus n. gen. ( Fig. 3 View FIGURE 3 A) (the tooth is stout with the dorsal surface distinctly convex in Eumedonus ; cf. Chia et al. 1995: fig. 3A); the cheliped merus is relatively long and unarmed ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 C) (relatively short with numerous tubercles and granules in Eumedonus ; cf. Chia & Ng 2000: figs. 8, 9B, 10, 11, 12B, L, 14, 15B, O); the meri of the ambulatory legs are long, subcylindrical and smooth, without any marginal cristae, and the dorsal distal tooth is relatively low ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 E) (short, laterally flattened with distinct marginal cristae and a strong dorsal distal tooth in Eumedonus ; cf. Chia & Ng 2000: figs. 8, 9E, G, 10, 11, 12E, K, 13, 14, 15E, K); the anterior male thoracic sternum (sternites 1–4) are proportionately narrow transversely ( Figs. 3 View FIGURE 3 C, 4B) (proportionately wider transversely in Eumedonus ; cf. Chia & Ng 2000: figs. 9C, 11B, 12C, 14B, 15N); and the male abdomen is relatively wide ( Figs. 3 View FIGURE 3 D, 4C) (proportionately narrower in Eumedonus ; cf. Chia & Ng 2000: figs. 12J, 14J, 15N).
The unarmed and non-cristate ambulatory meri of Cebudonus n. gen. resembles that of the echinoid symbiont Gonatonotus , but in the new taxon, it is proportionately much longer, more slender and almost smooth ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 E) (proportionately shorter and distinctly granular in Gonatonotus ; cf. Chia & Ng 2000: figs. 17, 18E, G, 20, 21E, K, 22, 23E, K). The differences previously noted in the form of the front, anterolateral region, cheliped, thoracic sternum and abdomen between Cebudonus n. gen. and Eumedonus also apply for Gonatonotus (cf. Chia & Ng 2000: figs. 17, 18A, D, 19A, 20, 21A, D, M, N, 22, 23A, D [front]; figs. 17, 18B, 20, 21B, 22, 23B [chelipeds]; figs. 17B, 19G, 20B, 21C, 22B, 23C [sternum]; figs. 19H, 21J, 22, 23J [abdomen]).
The form of the front, with the two long pseudorostral spines is similar to that of Tiaramedon and Zebrida , but these genera differ markedly from Cebudonus n. gen. in several other characters. Cebudonus n. gen., can be separated from Tiaramedon by its smooth dorsal surface of the carapace ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 ) (armed with additional gastric and branchial spines in Tiaramedon ; cf Chia & Ng 1998: figs. 7A, 8A); the two pseudorostral spines joining medially without any trace of a median plate ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 ) (with a small plate present between the pseudorostral spines in Tiaramedon ; cf. Chia & Ng 1998: fig. 8A, B); the chela is unarmed ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 F) (with an additional spine on the dorsal distal margin in Tiaramedon ; cf. Chia & Ng 1998: figs. 7A, B, 8K); the cheliped carpus has a single long inner spine ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 F) (2 large spines in Tiaramedon ; cf. Chia & Ng 1998: fig. 7A); the ambulatory merus is long and slender with a short dorsal distal tooth ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 E) (short and stout with a long distal dorsal tooth in Tiaramedon ; cf. Chia & Ng 1998: figs. 7, 8C); and the male anterior thoracic sternum is transversely narrow ( Figs. 3 View FIGURE 3 C, 4B) (transversely broad in Tiaramedon ; cf. Chia & Ng 1998: figs. 7B, 8D). The male abdomens of Cebudonus n. gen. and Tiaramedon are nevertheless similar in shape ( Figs. 3 View FIGURE 3 D, 4C; cf. Chia & Ng 1998: figs. 7B, 8F). The two genera are also different in terms of host specificity, with Tiaramedon always associated with crinoids (and with young crabs characteristically transversely striped like many other crinoid-associated eumedonines, see Castro et al. 1995; Chia & Ng 1995, 1998) whereas Cebudonus n. gen. with its longitudinal stripes is probably associated with echinoids.
Cebudonus View in CoL n. gen. can be separated from the echinoid symbiont Zebrida View in CoL by having two subcylindrical pseudorostral spines ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 ) (distinctly lamelliform in Zebrida View in CoL ; cf. Ng & Chia 2000: figs. 2, 3A, B); the lateral carapace tooth and the dorsal surface adjacent to the tooth is dorsally convex ( Fig. 3 View FIGURE 3 B) (the area is distinctly dorsally flattened in Zebrida View in CoL ; cf. Chia et al. 1995: fig. 3B); the chela and merus are unarmed and the carpus has a long spine at the inner angle ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 F) (the chela has a large subdistal dorsal tooth, the carpus and merus each having three large lamelliform teeth in Zebrida View in CoL ; cf. Ng & Chia 2000: figs. 2, 3J); the ambulatory merus is long and slender with a short dorsal distal tooth ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 E) (short and stout with the margins cristate to dentate and with a large distal dorsal tooth in Zebrida View in CoL ; cf. Ng & Chia 2000: figs. 2, 3C, K, M); the ambulatory propodus and dactylus are normal ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 D, E) (forming a subchelate clasping structure in Zebrida View in CoL ; cf. Ng & Chia 2000: figs. 2, 3C, K, M); and the male anterior thoracic sternum is proportionately narrower transversely ( Figs. 3 View FIGURE 3 C, 4B) (proportionately wider in Zebrida View in CoL ; cf. Ng & Chia 2000: figs. 2B, 3D). The male abdomens of Cebudonus View in CoL n. gen. and Zebrida View in CoL are similar, with both relatively wide transversely ( Figs. 3 View FIGURE 3 D, 4C; cf. Ng & Chia 2000: figs. 2B, 3F)
There are also similarities with Zebridonus View in CoL but Cebudonus View in CoL n. gen. can be separated by its two long pseudorostral spines ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 ) (with a distinctly dorsoventrally flattened lobiform pseudorostrum that is bifurcated distally to form two teeth in Eumedonus View in CoL ; cf. Chia et al. 1995: figs. 1, 2A, K); the lateral carapace tooth and the dorsal surface adjacent to it is dorsally convex ( Fig. 3 View FIGURE 3 B) (the area is distinctly dorsally flattened in Zebridonus View in CoL ; cf. Chia et al. 1995: figs. 1, 2A, 3C); the chela and merus are unarmed, and the carpus has a long spine on the inner angle ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 F) (the chela has a distinct distal dorsal tooth, the carpus 2 large lamelliform teeth and the merus several distinct teeth in Zebridonus View in CoL ; cf. Chia et al. 1995: figs. 1, 2 I); the ambulatory merus is long, subcylindrical and smooth, without any marginal cristae and the dorsal distal tooth is relatively low ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 4 View FIGURE 4 E) (short, laterally flattened with distinct marginal cristae and a strong dorsal distal tooth in Zebridonus View in CoL ; cf. Chia et al. 1995: figs. 1, 2B, C); the anterior male thoracic sternum (sternites 1–4) are proportionately narrower transversely ( Figs. 3 View FIGURE 3 C, 4B) (proportionately wider transversely in Zebridonus View in CoL ; cf. Chia et al. 1995: fig. 2D); and the male abdomen is proportionately wider ( Figs. 3 View FIGURE 3 D, 4C) (proportionately narrower in Zebridonus View in CoL ; cf. Chia et al. 1995: fig. 2F).
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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Brachyura |
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Eumedoninae |