The Australian Monstrilloida (Crustacea: Copepoda) II. Cymbasoma Thompson, 1888

Abstract

Monstrilloid copepods collected during the past two decades from zooplankton surveys in reef and coastal areas of Australia were analyzed. A first contribution included the taxonomic analysis of three genera of the Monstrilloida, Monstrillopsis Sars, 1921, Maemonstrilla Grygier & Ohtsuka, 2008, and the newly described Australomonstrillopsis Suárez-Morales & McKinnon, 2014. In this document a taxonomic analysis of the species belonging to the genus Cymbasoma Thompson, 1888 is provided. A total of 28 species were found, most of them being undescribed. Seventeen species were described based on females only and eight on male specimens while three species were described from both sexes. Males of Australian species of Cymbasoma are distinguished by details of the genital complex, body size and proportions, ornamentation and processes of the cephalic region, number of caudal setae, and the characteristic structure or ornamentation of the genital lappets. Two main groups of males were distinguished on the basis of the number of caudal setae (3 or 4). As for the females, 20 of the 25 new species of Cymbasoma have fifth legs with an unarmed inner lobe and three setae on the outer lobe; one of these species (C. jinigudira sp. nov.) belongs to the C. longispinosum species-group (sensu Üstün et al. 2014). Another group, consisting of five species, has only two setae on the outer (exopodal) lobe. There were no Australian species of Cymbasoma with a single lobe. A species group, named after C. agoense, is proposed to include species sharing a globose body and a female fifth leg with a large endopodal lobe and an outer (exopodal) lobe with two setae. The females of the new species of Cymbasoma from Australia can be distinguished from their known congeners by unique combinations of characters including the type of body ornamentation, body size and shape, antennule armature and proportions, the presence of distinctive features of the legs 1–4, the presence/absence of processes on the genital compound somite, and the presence/absence of a constriction of the anal somite. We report the occurrence of two previously described species, C. agoense Sekiguchi, 1982 from Japan and C. bali Desai & Krishnaswamy, 1962 from India in Australian waters. Considering the addition of the 25 new species here described, the number of nominal species of the genus is now 66. A key to the Australian species of Cymbasoma (males and females) and a map showing their occurrence in Australia are also provided.

A new species of Monstrillopsis (Crustacea, Copepoda, Monstrilloida) from the lower Northwest Passage of the Canadian Arctic

“…However, there are extended geographic areas in which the presence of monstrilloid copepod fauna remains unknown (Suárez-Morales 2011). As a result, local and regional lists are expected to grow as the exploration of under-sampled regions continues (Suárez-Morales 2011, Suárez-Morales and McKinnon 2014, 2016; Lee et al 2016). Currently, there are only a few species of monstrilloids known from Arctic or Subarctic waters (Fontaine 1955; Davis and Green 1974; Suárez-Morales and Ivanenko 2004).…”

A New Species of Monstrillopsis Sars, 1921 (Copepoda: Monstrilloida) with an Unusually Reduced Urosome

“…The most stunning morphological character of the present males is the unusually low number of somites in the urosome. Up to now, both sexes of Cymbasoma have been known to have the fewest urosomal somites among the known monstrilloid genera-females with three, including post-genital somite, and males with four, including post-genital and penultimate somites [8,20,21]. Males of the present new species have one fewer somite than males of Cymbasoma while matching the number in females of Cymbasoma.…”

“…The species of Cymbasoma, for instance, have been distinguished from the other monstrilloid genera based almost on this criterion alone [38][39][40]. A review of the most recent 20 years of taxonomic works dealing with over 40 species of Cymbasoma (more than half of the total species recorded in this genus) shows that authors continue to use this feature as the primary feature for generic assignment [20,22,[41][42][43][44][45][46]. In light of this history, the even lower number of urosomal somites in the present specimens may provide grounds for proposing a new genus of Monstrilloida.…”

“…As well, research into monstrilloid diversity has been expanding into lesser-studied regions. For example, Suárez-Morales and McKinnon [6,20] recently described 34 species of four genera from Australian waters, with a promised treatment of similar numbers of Australian Monstrilla still to come, and such findings imply the possible occurrence of large numbers of undescribed taxa in other such areas as well.…”

Recognition and partial solution of nomenclatural issues involving copepods of the family Monstrillidae (Crustacea: Copepoda: Monstrilloida)

“…Cymbasoma lenticula Suárez-Morales & McKinnon, 2016. The specific name is spelled two ways in its original description by Suárez-Morales & McKinnon (2016), mostly as C. lenticula, but also as C. lentilum on p. 95. We take this opportunity to act as First Revisers under Article 24.2.3 of the Code and fix C. lenticula as the correct original spelling.…”