Phylum: Arthropoda, Crustacea Cumella vulgaris Class: Multicrustacea, Malacostraca, Eumalacostraca Order: Peracarida, Cumacea The ghost shrimp Family: Nannastacidae Description chamber (Watling 2007). Size: In the original description by Hart Eyes: Conspicuous and circular in fe- (1930) from Vancouver Island, an ovigerous males (Gonor et al. 1979) (Fig. 1). In males a female was 2.5 mm in length and a male, single central sessile eye, with seven equal 3.0 mm long (Hart 1930). The illustrated lenses, is more prominent (Gonor et al. 1979) specimens (from Coos Bay) include a fe- (Fig. 4). male, 2.5 mm long, and a young male, 2.1 Antennae: Female antennule is rather mm in length. Cumella vulgaris is one of the stout, not easily visible, and with rudimentary smallest cumacean species (Sars 1900). inner flagellum (Nannastacidae, Fage 1951). Color: Males are dark brown except for ligh- The second antenna in females is with two ter distal segments and appendages. The large plumose setae (Hart 1930) (not figured). female carapace and sixth pleonite are dark Mouthparts: Mandibles are not unique brown and the rest of the body is light brown and the bases are not massive (Fage 1951) or white (Gonor et al. 1979). (not figured). General Morphology: Cumaceans are eas- Carapace: Female carapace is large ily recognizable by a large and inflated cara- and deep, with a smooth mid-dorsal carina pace and a (relatively) slender, flexible thor- (ridge) with a depression on each side (on ax and abdomen (Kozloff 1993; Gerken and posterior margin). A deep antennal notch is Martin 2014) (Fig. 1). Their bodies can be present, with an acute antero-lateral angle divided into these three major regions: the (Fig. 1). The male carapace is slender, the cephalon (head) that is covered by a cara- antennal notch is not as deep as in females, pace and includes the first five pairs of ap- and the dorsal carina is almost absent (Fig. pendages (antennae, mandibles, maxillae, 3). collectively the mouthparts). Posterior to Rostrum: Two pseudorostral lobes the cephalon is the pereon (thorax), usually (together called a pseudorostrum), or exten- consisting of five thoracic somites, followed sions of the carapace, extend anteriorly but by the pleon (abdomen) with consistently do not fuse in front of the head in cumaceans six pleonites. The fifth pleonite is usually the (Watling 2007). The pseudorostrum in female longest and the pleonites are lacking pleo- C. vulgaris is relatively short, minutely serrate pods in female individuals. The cumacean anteriorly and strongly pronounced (Fig. 1). family Nannastacidae are characterized by In males, the pseudorostral projection is shor- the lack of a free telsons and uropod endo- ter (Sars 1900) (Fig. 3). pods that are uniarticulate (Watling 2007). Pereon: Consists of five thoracic somites, (For general morphology of C. vulgaris, see each with paired appendages (pereopods) also Plate 229B, Watling 2007.) (Figs. 1–3). Cephalon: A carapace covers the cephalon Pereopods: The first pereopods in fe- and first three thoracic somites and is ex- males are with bases serrate on the outer dis- panded on either side to form a branchial tal margin. The dactyl and propodus are A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] Hiebert, T.C. and L. Rasmuson. 2015. Cumella vulgaris. In: Oregon Estuarine Invertebrates: Rudys' Illustrated Guide to Common Species, 3rd ed. T.C. Hiebert, B.A. Butler and A.L. Shanks (eds.). University of Oregon Libraries and Oregon Institute of Marine Biol- ogy, Charleston, OR. equal to the carpus in length. The second uropods, a strong carapace carina, and exo- pereopods are stout, and the dactyl is twice podites that appear only on the first two pairs as long as the propodus. The exopodites of pereopods. Males have a compound eye, are present on the first two pairs of are slim, lack a strong carapace carina and pereopods only (Cumella, Lie 1969). The have a very long second antenna. Males also last three pereopods are stout (Fig. 1). The have four pereopod exopodites and some first four pereopod bases in males are more uropod distinctions. dilated than in females and exopodites are Possible Misidentifications present on the first four pereopods (absent Cumaceans are very small (range 1 on fifth) (Figs. 2, 3). mm–1 cm) shrimp-like crustaceans. Their Pleon: Long and narrow in males and stou- heads and thorax are fused to form a ter in females. Consists of six articles or carapace, the abdomen is tubular and the pleonites, and lacking pleopods (Figs. 1, 3). uropods are slender and biramous. There are Pleopods: All female cumaceans 1500 species worldwide, approximately 50 of lack pleopods (Fig.1) and males in the family which occur on the Pacific coast of the United Nannastacidae also lack pleopods (Watling States (Watling 2007; Gerken and Martin 2007) (Fig. 3). 2014). Cumaceans belong to the Telson: Telson short, not freely articulated Malacostraca, and are characterized by a and fused to sixth abdominal article carapace that covers the first three or four (Nannastacidae, Watling 2007) (Figs. 1, 3). thoracic somites. They also have an anterior Uropods: The uropod peduncles in females extension (pseudolobes), a telson that is have inner margin with only one spine on present or reduced and fused with the last the inner distal angle (Gonor et al. 1979) pleonite, eyes that are united dorsally, a (Fig. 6). The uropod endopod is uniarticu- second antenna that is without an exopod and late (compare to biarticulate endopod in Nip- pleopods that are absent in females and can poleucon hinumensis), larger than exopod, be absent or reduced in males (Watling denticulate on inner margin, with two stout 2007). spines, and one strong apical spine. The The superorder Peracarida includes exopod is with two articles (as in all cu- cumaceans, mysids, isopods, tanaids and maceans), is ½ the width of the endopod, amphipods. Cumaceans can be separated and with one slender apical spine (Fig. 6) from mysids by their single compound eye (Gonor et al. 1979). The uropods of males (particularly in the males), as mysids have are slim and the peduncle is denticulate, lon- large stalked eyes. Mysids have a carapace ger than rami (Fage 1951), and with three which covers the entire thorax, while distal spines. The endopod is with only a cumaceans have several posterior segments single article (Nannastacidae, Watling exposed (e.g. Figs. 1, 3). Euphausiids belong 1979), while the exopod is with two articles to the superorder Eucarida (along with (Fig. 5). decapods) and are pelagic and marine, but Sexual Dimorphism: Quite strong sexual might occasionally be found in estuaries. dimorphism is observed in C. vulgaris. Fe- They have biramous thoracic appendages males are generally shorter and stouter than (cumacean pereopods are uniramous, with males and mature individuals have a brood some thoracic exopodites). Additionally, pouch. The female eye lacks the obvious euphausiids have strong pleopods for large lenses found in males (Fig. 4). Female swimming and cumacean pleopods, when specimens have a broader carapace and A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: https://oimb.uoregon.edu/oregon-estuarine-invertebrates and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] present, are small. Campylaspis hartae has a carapace with The four local cumacean families can large ridges, but no bumps, and C. rubroma- be divided into those with a freely articulated culata has a carapace with a series of bumps telson and those without, the former com- or tubercles and shallow ridges (Watling prise the Lampropidae and Diastylidae, 2007). while the latter comprise the Leuconidae The Leuconidae (like the Nannastaci- and Nannastacidae (Watling 2007). Cuma- dae) lack an independent telson. However, cean families that lack an articulated telson they always have a biarticulate uropod endo- are consistently monophyletic on molecular pod, not a uniramous one as in Nannastaci- phylogenies and are likely derived within the dae. Members of the Leuconidae often have Cumacea (Haye et al. 2004). However, up to two pairs of male pleopods (there are morphological characters used to differenti- none in Nannastacidae) and leuconid males ate cumacean families (e.g. number of pleo- have exopodites on all five pairs of pereopods pods in males) may be homoplasious (see (rarely on three). Leuconid females have ex- Haye et al. 2004). opodites on four (rarely on three) pairs of The family Nannastacidae, in which pereopods (Watling 1979). Thus, numbers of Cumella occurs, lack an independent telson, pereopodal exopodites in both sexes are too the males have no pleopods and the alike in the families Leuconidae and Nan- endopod of the uropod is uniarticulate. nastacidae to serve as dependable determin- Pereopodal exopodites in the ing characters. Of the Leuconidae, the gene- Nannastacidae are as follows: males have ra Eudorella, and Nippoleucon (see N. five (rarely four or three) pairs and females hinumensis, this guide) occur on the Pacific have three (rarely four or zero) pairs Coast (each with one local species). (Watling 1979). Cumella vulgaris is the only The Lampropidae and Diastylidae have species in this genus locally. However, C. a freely articulated telsons and the former pygmaea, the European species is very like family has three or more terminal setae on the C. vulgaris in color and size. The female of telson while the latter has 0–2. The Lam- C. pygmaea is stouter than C. vulgaris, with propidae includes six local species in the gen- a less inflated carapace and with a dentate era Hemilamprops and Mesolamprops (each crest on the carina.