Nippoleucon Hinumensis Class: Malacostraca Order: Cumacea Family: Leuconidae

Phylum: Arthropoda, Crustacea Nippoleucon hinumensis Class: Malacostraca Order: Cumacea Family: Leuconidae

Taxonomy: Nippoleucon hinumensis was Cephalon: A carapace covers the cephalon described as a member of the genus and first three thoracic somites and is Hemileucon at the same time many other expanded on either side to form a branchial cumacean species were described, in the chamber (Watling 2007). early 1900s. Walting revised the Leuconidae Carapace: Female carapace with a in 1991 and described the first new leuconid wide antennal notch that is pronounced into a genera since 1907. In his manuscript, tooth at an anterolateral angle (Fig. 1). Watling transferred two Hemileucon species Anterior and posterior edges are slightly (including H. hinumensis) to the newly serrate and the anterior half of the carina erected genus Nippoleucon based on (ridge) is finely and irregularly serrate. (Jones morphological characters (e.g. male antenna 1963 found two oblique ridges on the two, peduncular articles, Watling 1991) (Lee carapace sides, which were not observed and Lee 2003). here.) The carapace in males has an anterolateral edge that is not pronounced into Description a tooth and no serrations on anterolateral or Size: The illustrated males and females are lower edges (Jones 1963) and no antennal both 5 mm in length (from the Columbia River notch (Calman 1907) (Fig. 2). Estuary). Rostrum: Two pseudorostral lobes Color: Descriptions of color in the Cumacea (together called a pseudorostrum), or are difficult as many species were described extensions of the carapace, extend anteriorly based on preserved material, where the color but do not fuse in front of the head in fades. cumaceans (Watling 2007). The General Morphology: Cumaceans are pseudorostrum in female N. hinumensis is easily recognizable by a large and inflated abruptly upturned (Fig. 1) and is more carapace and a (relatively) slender, flexible horizontal and truncate in males (Fig. 2). thorax and abdomen (Kozloff 1993; Gerken Eyes: None in either sex. and Martin 2014). Their bodies can be Antennae: Antennae one are non- divided into these three major regions: the unique and short in females while antennae cephalon (head) that is covered by a two are rudimentary (Jones 1963). In males, carapace and includes the first five pairs of the second antenna has a peduncle with five appendages (antennae, mandibles, maxillae, articles and a long flagellum (12 segments) collectively the mouthparts). Posterior to the that extends into the second thoracic segment cephalon is the pereon (thorax), usually (Calman 1907) (Fig. 3). consisting of five thoracic somites, followed by Mouthparts: Two pairs maxillae and the pleon (abdomen) with consistently six three pairs maxillipeds. Mandibles are with pleonites. The fifth pleonite is usually the massive truncate bases, without palp and with longest and the pleonites are lacking strong molar process, incisor process and pleopods in female individuals. The lacinia mobilis (Fage 1951) (not figured). cumacean family Leuconidae are Pereon: Consists of five thoracic somites, characterized by the lack of a free telsons and each with paired appendages (pereopods). uropod endopods that are biarticulate Pereopods: Female pereopod (Watling 2007). (For general morphology of exopodites on somites 1–3 (Leuconidae, N. hinumensis, see also Plate 229A, Watling Stebbing 1913) (Fig. 1). Pereopods four and 2007.) five without exopodites (Fig. 5). Male

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12726 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] pereopod exopodites on pereopods 1–4, can be absent or reduced in males (Watling none on five (Calman 1907) (Figs. 2, 4). 2007). Pleon: Consists of six segments and the fifth The superorder Peracarida includes is longest. The telson is fused with the sixth cumaceans, mysids, isopods, tanaids and somite (Figs. 1, 2, 6). amphipods. Cumaceans can be separated Pleopods: All female cumaceans from mysids by their single compound eye lack pleopods and males in the genus (particularly in the males), as mysids have Nippoleucon also lack pleopods. large stalked eyes. Mysids have a carapace Telson: Telson not independent and fused which covers the entire thorax, while with last abdominal segment (Leuconidae) cumaceans have several posterior segments (Figs. 6). exposed. Euphausiids belong to the Uropods: Uropod peduncles longer than superorder Eucarida (along with decapods) abdominal segment six (Calman 1907) and and are pelagic and marine, but might more than 2/3 as long as the rami (Stebbing occasionally be found in estuaries. They 1913). Uropods are slender, cylindrical, and have biramous thoracic appendages biramous. The endopod inner branch is (cumacean pereopods are uniramous, with biarticulate. The first article of the endopod is some thoracic exopodites). Additionally, longer than the second, and is with nine euphausiids have strong pleopods for spines on the inner edge. The endopod is swimming and cumacean pleopods, when shorter than the exopod (Jones 1963) (Fig. 6). present, are small. The exopod (outer branch) is also biarticulate The four local cumacean families can be (as in all Cumacea, Watling 1979), has two divided into those with a freely articulated unequal terminal setae (Calman 1907; Jones telson and those without, the former 1963) (Fig. 6), and a series of setae on both comprise the Lampropidae (see Lamprops inner and outer edges (Calman 1907). The quadriplicata, this guide) and Diastylidae, uropods are similar in both sexes. while the latter comprise the Leuconidae and Sexual Dimorphism: Not as strong in this Nannastacidae (see Cumella vulgaris, this species as in those in which males have eyes guide) (Watling 2007). Cumacean families and pleopods. Males are more slender and that lack an articulated telson are longer than females. Males also have long consistently monophyletic on molecular second antennae. A brood pouch is present phylogenies and are likely derived within the in mature females only and is large, simple Cumacea (Haye et al. 2004). However, and transparent (not figured). morphological characters used to differentiate cumacean families (e.g. number Possible Misidentifications of pleopods in males) may be homoplasious Cumaceans are very small (range 1 mm– (see Haye et al. 2004). 1 cm) shrimp-like crustaceans. Their heads The Leuconidae (like the Nannastacidae) and thorax are fused to form a carapace, the lack the independent telson. However, they abdomen is tubular and the uropods are always have a biarticulate uropod endopod, slender and biramous. There are 1500 not a uniramous one as in Nannastacidae. species worldwide, approximately 50 of Members of the Leuconidae often have up to which occur on the Pacific coast of the two pairs of male pleopods (there are none United States (Watling 2007; Gerken and in Nannastacidae) and have exopodites on Martin 2014). Cumaceans belong to the all five pairs of pereopods (rarely on three). Malacostraca, and are characterized by a Leuconid females have exopodites on four carapace that covers the first three or four (rarely on three) pairs of pereopods (Watling thoracic somites and has an anterior 1979). Numbers of pereopodal exopodites in extension (pseudolobes), a telson that is both sexes are too alike in the families present or reduced and fused with the last Leuconidae and Nannastacidae and may not pleonite, eyes that are united dorsally, a serve as dependable characters for second antenna that is without an exopod identification. One of the oldest cumacean and pleopods that are absent in females and families (Watling 1991), the Leuconidae were recently been removed from the

Hiebert, T.C. 2015. Nippoleucon hinumensis. 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 Biology, Charleston, OR. Hemileuconidae (Given 1969). (This in Coos Bay, such as the North Bend Airport separation is not followed by Jones 1963, site and South Slough. however, see below.) Both families lack an Habitat: In sediment during the day and independent telson and both have a becoming planktonic at night. biarticulate endopod on the uropod. In Salinity: Leuconidae, however, there are usually two Temperature: pairs of male pleopods, rarely 1 or 0 pairs, Tidal Level: while there are no male pleopods in the Associates: Occurs with the cumacean, Hemileuconidae. Leuconid males have five Cumella vulgaris, where individuals are found (rarely three) pereopods with exopodites. at up to 5,600 individuals per square meter in Hemileuconid males, on the other hand, South Slough of Coos Bay (M. Posey, OIMB, have four pairs of pereopodal exopodites. unpublished data.) Male Leuconidae have second antennae that Abundance: Most common species found in are as long as the body, but they are shorter Columbia River estuary (R. Emmett, NOAA, in the Hemileuconidae (Given 1969). Astoria, personal communication). Female Leuconidae have four (rarely three) pairs of thoracic exopodites, while there are Life-History Information three pairs in the Hemileuconidae. Thus, it Reproduction: Development in cumaceans might be difficult separating females of these is direct, where eggs hatch within a two families. marsupium, and development is thought to be Two genera, Eudorella and Nippoleucon, similar among cumacean genera (e.g. each with a single species, are currently Leucon, Lamprops and Pseudocuma, Gerken reported from central California to Oregon and Martin 2014). The life-history of N. (Watling 2007). Eudorella pacifica has a hinumensis was documented by Akiyama and truncate edge to the carapace, like N. Yamamoto in 2004 from individuals collected hinumensis. Eudorella pacifica females, from Seto, Japan. In that region, ovigerous however, have a uropod exopod that is females are 1.2 times larger than males and shorter than the endopod. begin to incubate their first brood (containing The family Nannastacidae lack an 57 larvae) in February, often incubating a independent telson, the males have no second brood (containing 42 larvae) until late pleopods and the endopod of the uropod is April. In Manocuma stellifera, an Atlantic uniarticulate. The Lampropidae and intertidal cumacean, mating occurs at night in Diastylidae have a freely articulated telson plankton (Gnewuch and Croker 1973; Watling and the former family has three or more 1979), during the short swarming period. terminal setae on the telson while the latter Females molt 12–96 hours before oviposition has 0–2. The Lampropidae includes six local (in the lab). Eggs are probably fertilized as species in the genera Hemilamprops and they are released into the marsupium, where Mesolamprops (each with one local species) they are carried to nauplius larval stage. and the Lamprops (four local species, see L. Some other intertidal species have two quadriplicata, this guide). In the Diastylidae breeding generations per year, one in there are five local species in three genera summer and in fall (see Corey 1969, 1976 in including Anchicolurus and Diastylopsis (one Watling 1979). local species each) and Diastylis (three local Larva: Cumacean development proceeds species) (Watling 2007). from an egg to two manca stages, a subadult and finally, an adult. The manca stage Ecological Information resembles the adult, but is defined by a lack Range: Type locality is New Zealand, but this of the fifth pair of pleopods (see Fig. 41.1F, species was introduced to west coast Gerken and Martin 2014). In N. hinumensis, estuaries (e.g. San Francisco and Coos bays) manca larvae are released and most from Japan in ballast water (Castillo et al. recruitment takes place in April. Post- 2000; Watling 2007). marsupial individuals undergo eight in-stars in Local Distribution: Oregon distribution males and nine in females, with 10 days includes the Columbia River Estuary and sites between molts in the first four in-stars and two

A publication of the University of Oregon Libraries and the Oregon Institute of Marine Biology Individual species: http://hdl.handle.net/1794/12726 and full 3rd edition: http://hdl.handle.net/1794/18839 Email corrections to: [email protected] weeks thereafter (when not in diapause) subpopulation. Marine Ecology (Akiyama and Yamamoto 2004a). The Progress Series. 284:227-235. mancae of M. stellifera molt three times and 3. CALMAN, W. T. 1907. On new or rare the young leave the marsupium, molt several crustacea of the order Cumacea from more times into subadult morphology, with the collection of the Copenhagen mature gonads and secondary sexual Museum Part I, The families characteristics present (see Corey 1969, Bodotriidae, Vauntompsoniidae, and 1976 in Watling 1979). Leuconidae. The Transactions of the Juvenile: Zoological Society of London. 18:1-42. Longevity: The life-span of many cold water 4. CASTILLO, G. C., H. W. LI, and P. A. leuconid cumaceans is on the order of a few ROSSIGNOL. 2000. Absence of years. In Seto, Japan, population generation overall feedback in a benthic estuarine times occur on an annual cycle and the life- community: A system potentially span can be divided into three phases (see buffered from impacts of biological growth rate) (Akiyama and Yamamoto invasions. Estuaries. 23:275-291. 2004a). 5. FAGE, L. 1951. Cumacés. Faune de Growth Rate: France:1-136. Cumacean growth occurs in conjunction with 6. GERKEN, S., and J. W. MARTIN. molting where the exoskeleton is shed and 2014. Cumacea, p. 216-218. In: Atlas replaced. Post-molt individuals will have soft of crustacean larvae. J. W. Martin, J. shells as the cuticle gradually hardens. During Olesen, and J. T. Høeg (eds.). Johns a molt, arthorpods have the ability to Hopkins University Press, Baltimore, regenerate limbs that were previously MD. autotomized (Kuris et al. 2007). In N. 7. GIVEN, R. R. 1969. The Cumacean hinumensis, growth can be divided into three fauna of the Southern California phases: early growth from April to May, no continental growth (or diapause) from May to November shelf. No. 1, Family Leuconidae. and a later growth phase from December to Bulletin, Southern California Academy March (Akiyama and Yamamoto 2004a). This of Sciences. 60:129-146. summer period of diapause or arrested 8. GNEWUCH, W. T., and R. A. growth is unique to this species and, CROKER. 1973. Macrofauna of interestingly, not all populations undergo a northern New England marine sand. 1. diapause phase (see Akiyama and Biology of Mancocuma stellifera Yamamoto 2004b). (Zimmer, 1943) (Crustacea, Food: Filters small particles from below Cumacea). Canadian Journal of sediment surface or grazes on surface grains Zoology. 51:1011-1020. (Watling 1979; Kozloff 1993). 9. HAYE, P. A., I. KORNFIELD, and L. Predators: WATLING. 2004. Molecular insights Behavior: into Cumacean family relationships (Crustacea, Cumacea). Molecular Bibliography Phylogenetics and Evolution. 30:798- 809. 1. AKIYAMA, T., and M. YAMAMOTO. 10. JONES, N. S. 1963. The marine fauna 2004a. Life history of Nippoleucon of New Zealand: Crustaceans of the hinumensis (Crustacea: Cumacea: order Cumacea. Bulletin of the New Leuconidae) in Seto Inland Sea of Zealand Department of Scientific and Japan. I. Summer diapause and molt Industrial Research. No. 152:1-81. cycle. Marine Ecology Progress 11. KOZLOFF, E. N. 1993. Seashore life Series. 284:211-225. of the northern Pacific coast: an 2. —. 2004b. Life history of Nippoleucon illustrated guide to northern California, hinumensis (Crustacea: Cumacea: Oregon, Washington, and British Leuconidae) in Seto Inland Sea of Columbia. University of Washington Japan. II. Non-diapausing Press, Seattle.