Parvimysis pricei, Wittmann, 2020

Wittmann, Karl J., 2020, Revision of the genus Parvimysis (Mysida, Mysidae) with descriptions of five new species from coastal waters of the Caribbean, Zootaxa 4742 (1), pp. 1-30 : 7-9

Parvimysis pricei sp. nov.

http://zoobank.org/ urn:lsid:zoobank.org:act:6C8F13EB-E8F4-429C-A4AD-DDF31244C9C6

( Fig. 2 )

Parvimysis bahamensis, Brattegard, 1973 : fig. 19D; Price et al., 2002: 46–47, fig. 4M; Price & Heard, 2004: 155–156, fig. 4M–O.

Type material. Holotype, adult male with body length 2.0 mm in vial ( NHMW reg. no. 26578) and paratype 1 ♂ ad. 2.3 mm on slides ( NHMW 26577 ), Little Cayman Island , South Hole Sound , 19°40’03’’N 80°03’51’’W, 1–2.5 m, sand, epibenthic sled, 19 May 1995, night, leg. W. W. Price, R. Heard & J. Harris ; paratype 1 ♂ ad. 2.3 mm ( NHMW 26576 ), Little Cayman Island , South Hole Sound , 19°39’38’’N 80°04’22’’W, 1.5 m, sand, kicknet, 19 May 1995, daytime, leg. W. W. Price, R. Heard & J. Harris ; paratypes 17 ♀ ad. 2.1–2.4 mm in vial ( NHMW 26575 ) and 2 ♀ ad. 2.2 mm on slides ( NHMW 26581 ), Grand Cayman Island, North Sound, 19°23’24’’N 81°21’13’’W, 2–3 m, seagrass, epibenthic sled, 11 June 1997, night, don. W. Wayne Price.

Non-types. 1 ♀ ad. 2.4 mm ( NHMW 26579 ), damaged, Turks & Caicos Islands, Pine Cay, Twin Cay , 21°52’25.9’’N 72°04’11.5’’W, 0.5–1 m, algal washings, 14 Apr. 1988, daytime, leg. Richard Heard; another ♀ ad. 2.4 mm ( NHMW 26580 ), damaged, Turks & Caicos Islands, Pine Cay , “Aquarium”, N 21°51’38.3’’N 72°06’20.1’’W, 1–1.5 m, sand, kicknet, 13 Nov. 1989, daytime, leg. Richard Heard ; 2 ♀ ad. 2.2–2.3 mm, 6 ♂ ad. 1.8–2.2 mm, 5 subad., 3 imm. ( ZMBN 73149 ), stn. 37–67, Bahamas, Eleuthera, Pelican Cay, outside James Cistern, 25°16’45’’N 76°20’20’’W, 7 m, sand and coral heads, Ockelmann detritus sledge, 22 April 1967, leg. Torleiv Brattegard.

Type locality. Sublittoral marine waters of Little Cayman Island, 19°40’03’’N 80°03’51’’W .

Derivatio nominis. The species name is a Latinized noun in genitive singular, dedicated to W. Wayne Price (Tampa) in recognition of his important contributions to our knowledge of mysid taxonomy and diversity.

Definition. Parvimysis without or with a broadly rounded rostrum, in the latter case with freely projecting portion 0.0–0.2 times length of terminal segment of antennular trunk. Antero-lateral edges of the carapace produced into a short acute process. Eyes moderately large; maximum diameter of cornea 1.5–2.0 times the length of the terminal segment of the antennular trunk in dorsal view. Antennular trunk ending at about same height as the trunk of the antennal flagellum. Antennal scale varying from shorter to slightly longer than the trunk of the antennal flagellum; basal segment reaching to the middle up to the end of the terminal segment of the antennular trunk. Cardiac portion of foregut with simple, smooth spines; additional stout, modified spines on lateralia, not so on dorso-lateral infolding. Mandibular palp with terminal segment making up 14–17% total palp length. Its median segment subterminally with two basally barbed setae on inner margin; remaining portions of this segment smooth. Maxillary palp with proximal segment 0.3 times total palp length. Exopod of maxilla extends shortly beyond middle of the terminal segment of the palpus. Thoracic exopods 2–7 with 8-segmented flagellum. Thoracic endopods 1, 2 without claw; endopods 3–8 with moderately strong, weakly curved claw. Length of claw 5 is 9–10 times its width at basis. Endopods 3–8 with oblique articulation between carpus and propodus. Carpus of endopod 5 with comb-like series of setae on inner margin in males, normal setation in females. Oostegites normal. Exopod of fourth male pleopod 3-segmented, ending in large modified seta plus a minute lobe with minute seta (similar to Fig. 1N ). Apical segment of exopod is 0.5–0.6 times the length of the median segment. Scutellum paracaudale broadly rounded. Telson short, roughly trapezoid; its lateral margins slightly sinusoid, tapering, each armed with 2–4 short spines; each lateral margin ending in a short latero-terminal lobe with apical spine, the latter clearly longer than the lateral spines. Telson length 3.7–4.7 times distance between the latero-terminal spines. Telson terminally emarginate by 2–5% its length; 1–5 triangular denticles with 2–5% telson length emerge from the bottom of the emargination; denticles with 0.1–0.5 times length of latero-apical spines; no medio-terminal laminae and spines.

Description. All features of the diagnosis and those reported further above as common to the six Caribbean species of the present study. Size of adult males 2.0– 2.3 mm (n = 2), females 2.1–2.4 mm (n = 17).

Cephalic region ( Fig. 2 A–F). Cornea dorsoventrally weakly compressed, calotte-shaped in dorsal, oviform in lateral view, apparent length 1.3–1.5 times height in lateral view ( Fig. 2B ). Basal segment of antennular trunk about equal to combined median and apical segments in both sexes. Antennal scale with apical segment 27–36% length of the basal segment. Third segment of the trunk of the antennal flagellum with 62–86% length of the second segment. Median segment of mandibular palp with only 2–1 setae in subterminal position on inner margin, outer margin smooth all along. Terminal segment with two smooth setae, 3–5 modified setae bilaterally bearing series of stiff, spine-like barbs; and one longer seta with barbs along most of its distal 60–70%. Basal segment of maxillary palp with three barbed setae on inner margin, apical segment densely setose at tip and on distal 20–30% of inner margin, but lined by small hairs in more proximal portions. Each side of the foregut with one large, apically pronged, serrated spine ( Fig. 2E ) on mid-posterior part of lateralia; this spine with total of 12–13 teeth, among which 3–4 large teeth at tip. Group of 2–3 centro-apically serrated spines in even more posterior position on lateralia; the largest, most proximal spine ( Fig. 2F ) with total of 9–12 small teeth distributed only over apical 50–70% spine length.

Thorax ( Fig. 2 G–L). Length increases from exopod 1 to (4–6) and decreases from 6 to 8; length of endopods increases from 1 to 8. Basal plate of thoracic exopods 1–8 well rounded. Flagellum 7-segmented in exopods 1, 8. Thoracic endopod 8 slender; when stretched, extending forwards at most up to eyes and backwards to the end of pleonite 5. Dactylus of endopod 2 large, equipped with 7–8 modified setae (as in Fig. 4B ) plus a few smooth setae, no spine-like setae. Length and slenderness of claws increase in series of thoracic endopods 3–5, not clearly increasing in more caudal endopods; claw 3 is 6–8 times its width at basis, this relationship 9–10 in claw 8.

Pleon ( Fig. 2 M–S). Male pleopod 5 slender, 1.8–1.9 times length of pleopod 3. Male pleopod 4, when stretched, reaching to end of pleonite 5, its large apical seta up to the middle of pleonite 6. Fourth endopod 0.7–0.9 times length of basal segment of exopod; endopod with 9–11 barbed setae. Uropods with endopod 0.9 times length of exopod or 1.6–1.9 times length of telson (without spines). Length of exopod six times maximum width. Telson length 1.1–1.3 times width at basis, or 0.5–0.6 times length of exopod of uropods, or 0.5–0.7 times pleonite 6. Denticles with 0.3–0.6 times median length of lateral spines; size of denticles decreases with their increasing numbers at the terminal margin of the telson ( Fig. 2 Q–S).

Distribution. Cayman Islands, Turks & Caicos Islands, Bahamas and Florida Keys. Price et al. (2002) and Price & Heard (2004) reported this mysid as P. bahamensis from patchy seagrass beds and shallow-water sand habitats, also near deep fringing reefs and in algal washings.

Figures

FIGURE 1. Parvimysis bahamensis Brattegard, 1969, from the Bahamas, non-types: adult males with body length 2.3 mm (A–C, J, K, P), 2.1 mm (F, G, L–N, R), and females with 2.3 mm (D), 2.6 mm (E, O), 2.4 mm (H), 2.8 mm (Q); A, anterior body region of male, dorsal aspect (setae omitted from antennal scale), detail (B) shows left eye in lateral view; C, carapace expanded on slide; D, female antennula, dorsal; E, apically pronged, serrated spine from lateralia in the foregut; F, centro-apically serrated spine from posterior part of the lateralia; G, dactylus of thoracic endopod 3; H–K, thoracic endopod 5 in female (H) and male (J), detail (K) shows dactylus; L, dactylus of thoracic endopod 8; M, male pleopod 4, detail (N) shows tip of exopod; O, female pleopod 5; P, Q, variants of the scutellum paracaudale, lateral; R, telson.

FIGURE 2. Parvimysis pricei sp. nov. from Cayman Islands (A–R) and Bahamas (S), holotype, adult male with body length 2.0 mm (A, B, O), paratypes males 2.3 mm (C, G, J, K, M), 2.4 mm (L), females 2.2 mm (D–F, H, N, P, R), 2.1 mm (Q), nontype female 2.2 mm (S). A, anterior body region of male, dorsal aspect (setae omitted from antennal scale), detail (B) shows right eye in lateral view; C, carapace expanded on slide; D, female antennula, dorsal; E, apically pronged, serrated spine from lateralia in foregut; F, centro-apically serrated spine from posterior part of lateralia; G, dactylus of thoracic endopod 3; H–K, thoracic endopod 5 in female (H) and male (J), detail (K) shows dactylus; L, dactylus of thoracic endopod 8; M, male pleopod 4; N, female pleopod 5; O, P, variants of the scutellum paracaudale, lateral; Q–S, telson variants.

FIGURE 4. Thoracopods 1–7 in Parvimysis laminata sp. nov. from Curaçao, paratypes female with body length 2.5 mm (A), 3.2 mm (B, H), 2.9 mm (C, D), 3.1 mm (J), 3.0 mm (K), and males 2.8 mm (E), 2.5 mm (F, G); A, thoracopod 1 with sternites 1–4; B, endopod 2; C, endopod 3, detail (D) shows dactylus; E, endopod 4; F–H, endopod 5 in female (F) and male (G), detail (H) shows dactylus; J, endopod 6; K, endopod 7 with oostegite.