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| Faxonius roberti Fetzner & Taylor, 2018 |
Abstract
Two new species of freshwater crayfish are described from the Ozarks Plateau of northern Arkansas and southern Missouri. Both species are restricted to the mainstem of rocky streams that are at least fourth-order or greater in size. Recent genetic and morphological investigations of the coldwater crayfish, Faxonius eupunctus Williams, 1952, indicated that it was actually composed of several undescribed species. Faxonius eupunctus is herein restricted to just the Eleven Point River system. Faxonius roberti, new species is found in the mainstem of the Spring and Strawberry river systems in northern Arkansas. It differs from F. eupunctus by lacking a male Form-I gonopod with a distal spatulate mesial process, and presence of two spines on the dorsal side of the merus, where F. eupunctus typically has 1 spine. Faxonius wagneri, new species is known from a 54 mile (86 km) stretch of the Eleven Point River mainstem, ranging from just southeast of Greer, Missouri to just north of Birdell, Arkansas. Faxonius wagneri can be differentiated from both F. eupunctus and Faxonius roberti sp. nov. by using the male Form-I and Form-II gonopods, the shape of the chelae, and the female annulus ventralis. In F. wagneri, the terminal elements of the first pleopod are almost twice as long as those in F. eupunctus and F. roberti, with the tips of the appendage reaching the posterior base of the first perieopod when the abdomen is flexed forward, whereas, in the other two species, these elements only reach the base of the second pereiopod. The species also possesses two spines on the dorsal side of the merus of the first pereiopod, which helps distinguish it from F. eupunctus.
Keywords: Crustacea, crayfish, Faxonius, life history, morphology, new species, Orconectes, phylogeny
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| Dorsal view of Faxonius roberti new species, holotype, male form-I (CMNH 38749) from the type locality. |
Faxonius roberti, new species
Orconectes eupunctus Williams, 1952:334, pl. 1: figs. 1–8 [in part]; 1954:840, figs. 41–49 [in part].—Hobbs, 1974:19, fig. 116 [in part].
Orconectes (Crockerinus) eupunctus.—Fitzpatrick, 1987:51 [in part], Hobbs, 1989:36, fig. 154 [in part].
Faxonius eupunctus.—Crandall and De Grave, 2017:629 [in part].
Etymology. It is our great pleasure to name this species in honor of Robert (Bob) J. DiStefano of the Missouri Department of Conservation (MDC). Bob has worked tirelessly over his career to help understand and conserve the crayfish fauna of the Ozarks in general, and Missouri in particular, so it is fitting that this Ozarkian species be named in his honor. This new species should not be confused with “Orconectes bobi”, the ficticious species name assigned to Bob when he was wearing his full crayfish costume while conducting public outreach programs for the MDC.
Crayfish associates. The following species were collected from habitats containing Faxonius roberti, new species: Faxonius ozarkae (Williams, 1952); Faxonius marchandi (Hobbs, 1948) and Cambarus hubbsi Creaser, 1931.
Common name. The suggested common or vernacular name for this species is the Spring River Crayfish, which is in reference to its affinity for the mainstem channels of the two spring-fed rivers where the species occurrs.
Faxonius wagneri, new species
Orconectes eupunctus.—Williams, 1952 [in part].
Orconectes (Crockerinus) eupunctus.—Fitzpatrick, 1987 [in part], Hobbs, 1989 [in part].
Faxonius eupunctus.—Crandall and De Grave, 2017:629 [in part].
Etymology. This species is named in honor of Brian K. Wagner of the Arkansas Game and Fish Commission. Brian initially collected specimens of this species and noted that they looked different from the typical F. eupunctus, which are found in the same streatch of the Eleven Point River. Brian has worked extensively with the crayfish fauna of Arkansas, and it is our pleasure to name this species after him.
Crayfish associates. Other crayfish found in association with Faxonius wagneri include F. eupunctus (Williams, 1952), F. ozarkae (Williams, 1952), F. punctimanus Creaser, 1933 and Cambarus hubbsi Creaser, 1931.
Common name. The suggested common or vernacular name for this species is the Eleven Point River Crayfish, in reference to the river where the species is found.
James W. Jr. Fetzner and Christopher A. Taylor. 2018. Two New Species of Freshwater Crayfish of the Genus Faxonius (Decapoda: Cambaridae) from the Ozark Highlands of Arkansas and Missouri. Zootaxa. 4399(4); 491–520. DOI: 10.11646/zootaxa.4399.4.2
