Colerolumnus, Ng, Peter K. L., 2010
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publication ID |
https://doi.org/ 10.5281/zenodo.275841 |
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DOI |
https://doi.org/10.5281/zenodo.5664444 |
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persistent identifier |
https://treatment.plazi.org/id/9E5387EE-FFF2-D358-84AA-F942FB2AA545 |
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treatment provided by |
Plazi |
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scientific name |
Colerolumnus |
| status |
gen. nov. |
Colerolumnus View in CoL new genus
Type species. Planopilumnus fuscus Balss, 1933 , by present designation and monotypy.
Diagnosis. Carapace broader than long ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A); dense, short wool-like pubescence which does not form distinct patterns, smooth underneath or only with scattered granules ( Figs. 13 View FIGURE 13. A, B C, 14D); dorsal carapace regions convex, not demarcated by deep grooves ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A); epigastric, mesogastric, postorbital cristae not discernible, although areas with scattered granules ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A); posterolateral, posterior carapace, sub-branchial regions with scattered granules or ridges but never forming discrete channels ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A). Frontal margin with 2 subtruncate lobes separated by fissure; no lateral lobule discernible, margin contiguous with supraorbital margin ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A); supraorbital margin gently concave with single fissure ( Fig. 17 View FIGURE 17 A). Suborbital margin prominently dilated to form shelflike crest ( Fig. 17 View FIGURE 17 B). Anteroexternal angle of third maxilliped distinct but not prominently auricuiliform ( Fig. 17 View FIGURE 17 C). External orbital tooth triangular, anterolateral margin with 3 teeth, first 2 large, triangular, lobiform, third tooth very small, directed laterally ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A). Chelipeds distinctly unequal ( Figs. 13 View FIGURE 13. A, B C, 17E, F); almost entire outer surfaces of palms of both chelae covered with numerous granules, wool-like setae, tips of larger granules visible ( Fig. 17 View FIGURE 17 E, F). Ambulatory legs smooth, without distinct granules, crests or ridges; surfaces completely obscured by numerous long, short setae ( Figs. 13 View FIGURE 13. A, B C, 17G). Anterior thoracic sternum relatively wide, surfaces with scattered granules; surface of anterior thoracic sternum smooth or with scattered small granules ( Fig. 17 View FIGURE 17 D, 18A); sternites 1, 2 completely fused without trace of suture; s2/3 complete; s3/4 almost complete but medially very shallow, almost undiscernible; s4/5, s5/6, medially interrupted; s6/7, s7/8 complete; longitudinal median groove present from sternites 6-8; male press button distinct, positioned on anterior part of sternite 5. Male abdomen triangular; outer surfaces almost smooth; all abdominal somites, telson mobile ( Fig. 18 View FIGURE 18 A). G1 very slender, sinuous, distal part tapering to sharp or rounded tip ( Fig. 18 View FIGURE 18 B–E). G2 about one fifth or less length of G1 ( Fig. 18 View FIGURE 18 F).
Etymology. The name is derived from the Greek "koleros" for short-wooled; in arbitrary combination with the genus Pilumnus . The gender of the genus is masculine.
Remarks. The carapace of Colerolumnus fuscus new combination is superficially similar to that of Planopilumnus spongiosus and Rathbunaria orientalis in its general shape, relatively flat dorsal surface and form of the anterolateral margin, and it was probably these reasons why Balss (1933) originally referred Planopilumnus fuscus to this genus. The pubescence on C. fuscu s, however, is quite different, being much longer and softer than that in P. spongiosus and R. orientalis . Most significantly, the structures of the G1 and G2 are typically pilumnid. The G1 is slender and sinuous (stout and almost straight in Planopilumnus and Rathbunaria ), and the G2 is short, sigmoidal and less than a quarter the length of the G1 (about half the length of the G 1 in Planopilumnus and Rathbunaria ). Compared to Ve ll u mnu s new genus, Colerolumnus can easily be distinguished by its setae been uniformly distributed on the carapace ( Figs. 13 View FIGURE 13. A, B C, 14D) rather than in clear tracts ( Fig. 13A View FIGURE 13. A, B ), the dorsal surface of the carapace is almost smooth, without ridges ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A) (with prominent ridges or granule rows in Vellumnus ; Fig. 15 View FIGURE 15 A), the anterolateral teeth with two large teeth and one small one ( Figs. 13 View FIGURE 13. A, B C, 14D, 17A) (with three subequal teeth in Vellumnus ; Figs. 14A View FIGURE 14. A – C , 15 View FIGURE 15 A), the presence of the shelf-like suborbital margin ( Fig. 17 View FIGURE 17 B) (normal non-cristate or expanded margin in Vellumnus ; Fig. 13B View FIGURE 13. A, B ) and the relatively broader male anterior thoracic sternum ( Fig. 17 View FIGURE 17 D) (proportionately narrower in Vellumnus ; Fig. 14B View FIGURE 14. A – C ). Compared to the rest of the Pilumnidae (sensu Ng et al. 2008), there is no species which has the carapace form and the prominent suborbital margin (shelf-like) observed in C. fuscus .
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.