Mimulus Stimpson, 1860, a junior synonym of Pugettia Dana, 1851 (Decapoda: Brachyura: Majoidea: Epialtidae)
Wicksten, Mary K.
Stachowicz, John J.
Zootaxa
2013
3693
3
358
364
7PX27
Dana, 1851
Dana
1851
[238,487,428,455]
Malacostraca
Epialtidae
Pugettia
Animalia
Decapoda
1
359
Arthropoda
genus
MimulusStimpson, 1860: 199.—A. Milne-Edwards 1878: 144.—Holmes 1900: 23.—Rathbun 1904: 173.—Rathbun 1925: 182.—Schmitt 1921: 204.—Garth 1958: 183.—Ng et al. 2008: 101.—Wicksten 2012: 208. Typelocality Puget Sound, Washington. Species included Pugettia dalliRathbun, 1894 Pugettia elongataYokoya, 1933 Pugettia foliata(Stimpson, 1860) Pugettia gracilisDana, 1851( typespecies) Pugettia hubbsiGarth, 1958 Pugettia incisa( DeHaan, 1839) Pugettia intermediaSakai, 1938 Pugettia kagoshimensisRathbun, 1932 Pugettia leytensisRathbun, 1916 Pugettia marissinicaTakeda & Miyake, 1972 Pugettia mindanaoensisRathbun, 1916 Pugettia minorOrtmann, 1893 Pugettia nipponensisRathbun, 1932 Pugettia ogasawaraensisKomatsu, 2011 Pugettia producta(Randall, 1840) Pugettia quadridens( DeHaan, 1839) Pugettia pellucensRathbun, 1932 Pugettia richiiDana, 1851 Pugettia similisRathbun, 1932 Pugettia tasmanensisRicherde Forges, 1993 Pugettia venetiaeRathbun, 1924
Remarks.In his Latin description (translated by Holmes 1900), Stimpson (1860) defined the genus as: “ Carapace flattened, more or less pentagonal; antero-lateral margin laminate and cut by a narrow fissure into two closely approximate lobes. Rostrum short, bifid, and horizontal. Orbits incomplete below, but furnished above with a preorbital and postorbital spine. Eyes not concealed when retracted. Merus of the external maxillipeds short, the external angle obtuse, the internal angle incised; outer margin of the exognath dilated. Hand of the chelipeds much compressed and sublaminate. The propodi of the ambulatory legs have a setose tooth near the middle of the inferior margin. First pair of ambulatory legs exceeding the others.” Stimpson stated "this genus is near Epialtus, with lamellar expansions of the sides of the carapax as in some Hueniae". The narrow chelipeds shown in the original illustration demonstrate that this individual was a female (Stimpson 1860: pl.1A). The typelocality was “taken from the stomachs of percoid fishes, (“Cabesones”) caught off Monterey, California, by A.S. Taylor”. Cabezon is the common name of Scorpaenichthys marmoratus(Ayres, 1854), family Cottidae, a crab-eating fish. Stimpson made no mention of or made comparison to species of Pugettia. Stimpson’s specimens were housed in the Chicago Academy of Sciences, which was destroyed in a fire in 1871. The typespecimen almost surely was destroyed. Garth (1958) reported that a “male cotype without chelipeds or legs” existed in the Museum of Comparative Zoology, Harvard University, but no syntypesof M. foliatushave been found in the British Museum (Natural History) (Evans 1967). FIGURE 1. Pugettia foliata(Stimpson, 1860). A, Original illustration of Mimulus foliatus(Stimpson 1860: plate 5, fig. 1). B, Adult male from Monterey Bay, California. Scale = 10 mm. Photograph by T.J. Boyle, Texas A&M University. C, Adult male from Sonoma County, California. Photograph by Kristin Hultgren, Seattle University. A. Milne-Edwards (1867) described a second species, Mimulus acutifrons, which supposedly could be distinguished from M. foliatusby the “frontal teeth” (rostral horns), which are “short and hardly separated from the median line, and by the supra-orbital angles not reaching as far” (translated from the French). There were no illustrations and there was only a single specimen (sex not stated), and no information on the typelocality was given except that the specimen had been part of the collections of “Baron de Lafresnaye”. The typematerial, which seems to have been deposited in the Muséum National d’Histoire Naturelle, Paris, is apparently lost (D. Guinot, pers. comm.) Garth (1958) questionably placed M. acutifronsin synonymy with M. foliatus. The length of the rostral horns is variable in specimens of M. foliatus, and the supra-orbital angles can vary with age and sex. It is impossible without the examination of the holotypeto know for certain if Milne-Edwards’ specimen could be assigned to Mimulusor a related genus, or in which localities one might look for a similar specimen. Newcombe (1893) contacted M.J. Rathbun regarding a specimen collected in Clayoquot Sound, British Columbia. She stated that she was “unable to separate the genus from Pugettia”. Newcombe (1893) recorded the species as Pugettia( Mimulus) foliataStimpson. Rathbun (1894:72)wrote "there seems to be no good reason for placing this ( Mimulus foliatus) in a genus distinct from Pugettia," and referred to the species as Pugettia foliata. The "antennae have the basal joint as in that genus" ( Pugettia) and the flagellum is flattened and exposed at the side of the rostrum, the "carapace is wider than in other species of Pugettia" and the chelipeds present showed "nothing distinctive". The maxillipeds, abdomen, sternum, and ambulatory legs were considered as "almost exactly" as in Pugettia gracilisDana, 1851. Holmes (1900: 23) translated Stimpson's original Latin description of Mimulusbut made no comparisons to species of Pugettia. Without explanation, he cited Pugettia foliata,as given by Rathbun (1894), as a junior synonym of M. foliatus. Rathbun (1904: 173) referred it as M. foliatus. Schmitt (1921), Rathbun (1925), and Garth (1958) considered Mimulusa valid genus, containing only one species, M. foliatus. Garth’s work provided a brief re-description of the species along with illustrations, and Garth (1958) and Wicksten (2012) provided extensive synonymies. Schmitt (1921), Rathbun (1925), and Garth (1958) distinguished species of Pugettiafrom Mimuluson the basis of the lateral margins of the carapace being markedly flattened or produced. Schmitt (1921) stated that the upper surface of the carapace of Pugettiabore spines or tubercles instead of being smooth, and assigned P. productaRandall, 1839, to EpialtusH. Milne-Edwards, 1834. The dorsal surface of the carapace of P. productais smooth. Schmitt's description of M. foliatusnoted that it possessed two median "obsolescent" tubercles as well as a tubercle on the posterior branchial region, and thus contradicted the generic distinction from Pugettiagiven in his key. Garth (1958: pls. L, O, P, Q) figured the right first pleopods of male epialtid crabs (as subfamilies Acanthonychinae and Pisinaeof the Majidae), including M. foliatus, P. producta, P. richii, four other Pugettiaspecies, and Talipeus nuttallii. In both M. foliatusand the species of Pugettia, this pleopod bears a flared apex with a pointed tip and one or two opposing grooved projections of equal or slightly shorter length. Both M. foliatusand the species of Pugettiabear some form of median protuberance: a spinulous lobe, "tongue," rounded lobule, or two smaller lobes. In contrast, the first pleopods of T. nuttalliido not have the median protuberance, and the lateral projections are not curved, as in Pugettia. The male pleopods of other species of Epialtidaevary, ending in a curved, spiny, or flattened apex, two concave points, small and blunt lobes or a complicated structure of depressed areas and protrusions. The shapes of the distal areas of the male first pleopods of M. foliatus, P. producta P. richii, and T. nuttalliiare in close agreement with those figured by Garth. Griffin & Tranter (1986: fig. 28) figured the male first pleopods of the western Pacific P. incisa, P. intermedia, P. marissinica, and P. quadridens. Komatsu (2011), in the original description of P. ogasawarensis, and Richer de Forges (1993), in the original description of P. tasmanensis, also figured the first pleopods. The pleopods of all of the western Pacific and Tasman Sea species have similar apices, only varying in fine details of the angle, length, and curvature of the lobes and tubercles. The structure of the first pleopod of male M. foliatusfalls within the range of species variation of the genus Pugettia. Hultgren & Stachowicz (2008a) studied the habitat distinctions between P. producta, P. richii, and M. foliatus. These three species can be found in intertidal areas along the coast of California, but have distinct habitats: P. productais usually found among large kelps, ( Macrocystisor Egregiaspp.), P. richiiamong red algae (Rhodophyta), and M. foliatustypically in the lowest intertidal zone into shallow subtidal regions, on rocks, among algae, or in kelp holdfasts ( Fig. 1C). The relatively smooth carapaces of P. productaand M. foliatusmay be related to climbing on algae or hiding among kelp holdfasts. Of the three species, only P. richiidecorates by attaching algae or hydroids to its rostrum and the sides of the carapace. The other two species may attach a small piece of alga to the rostrum but do not cover the body from dorsal view. The three species share similar ranges: P. productafrom the Queen Charlotte Is., Canadato Point Asunción, Baja California, Mexico; P. richiifrom Prince of WalesI., Alaska to Asunción Bay, Baja California; and M. foliatusfrom Unalaska, Alaska to San Diego, California, although it is uncommon south of Point Conception, California. A report of M. foliatusfrom Mazatlán, western Mexicois "questionable" (Garth 1958). Hultgren & Stachowicz (2008b) used a genetic analysis to study the relationships among majoid crabs. The study included members of the Epialtidae, including six species of Pugettia, M. foliatus, and Taliepus nuttallii.It was found that M. foliatuswas as closely related to other species of Pugettiaas species of Pugettiawere to each other. Aspointed out by Rathbun (1894: 72), the closest relative to M. foliatusseems to be P. gracilis. Hultgren & Stachowicz (2008b) suggested, but did not confirm, that Mimulusshould be considered to be a junior synonym of Pugettia. Stimpson (1860) and subsequent authors gave great importance to the lateral flattened expansions of M. foliatus, as seen in the "Hueniae", as a difference with other majoid crabs. The first author examined specimens of Huenia heraldica( DeHaan, 1837) (Epialtidae)in the collections of the Bishop Museum, Honolulu, Hawaii. In H. heraldica, the shape of the lateral expansions of the carapace is sexually dimorphic, with those of the female being less sharply defined than those of them male. These lateral expansions occur in other epialtoid crabs, such as Epialtoides hiltoni(Rathbun, 1894). Large, well-separated teeth along the lateral margin of the carapace in most species of Pugettia, but in P. gracilis, the anterolateral projections of the carapace have been described as "wing-like" (Garth 1958). Hultgren & Stachowiz (2008a) related the surface of the carapace to habitat, suggesting that crabs that climb among algae or hide under rocks might be more likely to have a smooth carapace than those living among dense algae. The function of the “wing-like expansions” of the carapace remains uncertain, but combined with a color similar to the algae on or among which they live, may help to conceal the crab in the natural habitat. Asin M. foliatus, adult male Pugettiafrequently have larger chelae than do mature females, often with a gape between the fingers, and a pronounced ridge along the carpus and the upper margin of the propodus ( Fig. 1B). These features are prominent in P. richii, P. dalli, and P. gracilisfrom the eastern Pacific; somewhat less so in P. productaand P. hubbsi; and in the Japanese species P. minor, P. incisa, P. quadridens, P. nipponensis, and P. sagamiensis(Sakai 1965: pls. 31–33). Species of Pugettia, with the exception of P. tasmanensis, are confined to the western and northern Pacific Ocean, ranging from the Philippinesnorthward along the Asian coast, across the Aleutian Islands south to Baja California, Mexico. Thirteen of the 21 species inhabit the area from the Philippinesto Russia, and seven are found in the eastern Pacific. P. tasmanensisis the only species reported from the southern hemisphere. In California, these are called “kelp crabs”, an appropriate name because many of them live among algae. Based on external morphology, structure of the male first pleopods, sexual dimorphism, habitat, range and new genetic data, we find no reason to separate Mimulus foliatusfrom the known species of Pugettia.We therefore place MimulusStimpson, 1860in synonymy with PugettiaDana, 1851. The revised name of the foliose kelp crab is hereby changed to Pugettia foliata(Stimpson, 1860).