Parvimysis bahamensis Brattegard, 1969

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 : 4-7

Parvimysis bahamensis Brattegard, 1969

( Fig. 1 )

Parvi mysis bahamensis Brattegard, 1969: 74–78 , figs. 23, 24; 1970: 127; 1973: fig. 19E.

Mysidops is cojimarensis Ortiz & Lalana, 1993 : fig. 1D; Price et al., 1994: 682 (in potential synonymy); Ortiz & Lalana, 2018: 67 (in synonymy).

Taxonomic assignment not clear for many additional references.

Holotype. Adult male with 2.6 mm body length ( AMNH reg. no. 13434), Caribbean, Bahamas, stn. 72–67, off Great Guana Cay , between White Point and Black Point, Exumas , 24°04’25’’N 76°23’45’’W, 3–4 m depth, sand bottom, 30 April 1967, leg. Torleiv Brattegard.

Paratypes. Three different samples with identical reg. no. ( AMNH 13435), Bahamas, leg. Torleiv Brattegard: one male 2.8 mm mounted on 4 slides (somewhat damaged by desiccation), labeled as paratype no. 1, and one female 3.1 mm on 9 slides as paratype no. 2, both from stn. 44–68, Conception Island, W of light, 23°49’20’’N 75°07’50’’W, 12–15 m depth, sand, Ockelmann detritus sledge, 23 March 1968, night; 4 ♂ 1.9–2.2 mm in vial, same sample as for holotype; 6 ♂ ad. 2.1–2.4 mm, stn. 37–67, 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. Five additional specimens labeled as paratypes of P. bahamensis from stn. 37–67 are here assigned to P. nuda sp. nov.

Non-types. 32 ♀ ad. 2.3–3.8 mm, 9 ♂ ad. 1.7–2.6 mm, 1 ♀ subad., 1 ♂ subad. ( ZMBN 73159 ), same sample as for holotype ; 47 ♀ ad. 2.2–2.9 mm, 24 ♂ ad. 1.8–2.7 mm, 24 subad., 10 imm., 3 juv. ( ZMBN 73149 ), same sample as for paratypes from stn. 37–67.

Type locality. Sublittoral marine waters of Bahamas, off Great Guana Cay, 24°04’25’’N 76°23’45’’W.

Diagnosis. Parvimysis with (sub)triangular rostrum, tip angular or narrowly rounded. Freely projecting portion of the rostrum 0.3–0.6 times the length of the terminal segment of the antennular trunk. Antero-lateral edges of the carapace produced into a short acute process. Eyes moderately large; maximum diameter of cornea 1.7–2.0 times the length of the terminal segment of the antennular trunk in dorsal view. Antennular trunk shortly extending beyond trunk of antennal flagellum or ending at about same height. Apical segment of antennal scale extending by about half to full length beyond trunk of antennal flagellum; basal segment not extending beyond 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 14–18% total palp length; median segment (sub)terminally with 0–2 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 3–7 with 8-segmented flagellum. Thoracic endopods 1, 2 without claw; endopods 3–8 with moderately strong, weakly curved claw. Length of claw 5 is 7–9 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 ( Fig. 1M, N ). Apical segment of this exopod is 0.4–0.5 times the length of the median segment. Scutellum paracaudale triangular with acute or narrowly rounded tip. Telson short, roughly trapezoid; its lateral margins slightly sinusoid, tapering, each armed with 2–5 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 2.7–3.0 times distance between the latero-terminal spines. Telson terminally emarginate by 10–20% its length; median lobe with 3–5% telson length emerges centrally from the bottom of the emargination; lobe with 2–5 laminae at tip, laminae 0.5–0.7 times length of latero-apical spines; no medio-terminal teeth and spines.

Description of types. All features of the species diagnosis and those reported further above as common to the six Caribbean species treated in the present study, with the reservation that the foregut was studied in non-types only. Holotype and all except five paratypes with laminae on median lobe projecting distad from the bottom of the telson cleft ( Fig. 1R ). Remaining five paratypes, namely four adult females and one adult male, with smooth, unarmed telson cleft (as in Fig. 9Q ), here assigned to the below-described P. nuda sp. nov. Holotype, paratype no. 1, and two other male paratypes of P. bahamensis with male-specific setal pattern ( Fig. 1J ) on carpus of thoracic endopod 5. This leg broken in the remaining male paratypes, including the single male here not acknowledged as P. bahamensis . Normal setation ( Fig. 1H ) in carpus 5 of all five female paratypes, including the four non-acknowledged females. The only here acknowledged female is paratype no. 2, dissected and figured by Brattegard (1969: Figs 23; 24A, B).

Cephalic region ( Fig. 1 A–D). Cornea dorsoventrally weakly compressed, calotte-shaped, 0.9–1.0 times length of eyestalk in dorsal view; oviform with length 1.1–1.3 times height in lateral view ( Fig. 1B ). Basal segment of antennular trunk about equal to combined median and apical segments in both sexes. Antennal scale with apical segment 23–31% length of basal segment. Third segment of trunk of antennal flagellum with 70–88% length of second segment. Apical segment of mandibular palp with two smooth setae, five modified setae bilaterally bearing series of stiff, spine-like barbs; and one longer seta with barbs along most of its distal 70%. Apical segment of maxillary palp densely setose at tip and on terminal 40–60% of inner margin, whereas lined by small hairs in more proximal portions.

Thorax ( Fig. 1 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, flagella 8-segmented throughout. Endopod 8 slender; when stretched, extending forwards shortly beyond the eyes or backwards to the end of pleonite 5. Dactylus of endopod 2 large, equipped with 5–6 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 3–8; claw 3 is 7–8 times its width at basis, claw 8 ten times. Penes with four small setae in subterminal position on inner face.

Pleon ( Fig. 1 M–R). Male pleopod 5 slender, 1.4–1.6 times length of pleopod 3. Male pleopod 4, when stretched, reaching to end of pleonite 5, its large apical seta ends at the middle of pleonite 6. Fourth endopod 0.8–1.1 times length of basal segment of exopod; endopod with 8–9 barbed setae. Uropods with endopod 0.8–0.9 times length of exopod or 1.5–1.6 times length of telson (without spines). Length of exopod 6–7 times maximum width. Telson length 1.1–1.2 times its width at basis, or 0.5–0.6 times length of exopod of uropods, or 0.6 times pleonite 6. Laminae with 0.6–0.8 times median length of lateral spines.

Supplements to the description. Using non-types from the Bahamas: size of adult males 1.7–2.7 mm (n = 39), females 2.2–3.8 mm (n = 83). Basal segment of maxillary palp with three barbed setae on inner margin. Penes with 4–14 minute setae facing the ejaculatory opening. Each side of foregut with one large, apically pronged, serrated spine ( Fig. 1E ) on mid-posterior part of lateralia; this spine with total of 15–20 teeth; tip of spine armed with 2–4 large teeth. Group of four centro-apically serrated spines in even more posterior position on lateralia; the largest, most proximal spine ( Fig. 1F ) with total of 9–12 teeth distributed only on apical 50–70% spine length.

Distribution and habitat. In euhaline waters of Bahamas, Cuba and Puerto Rico, depth 1–20 m, on sandy bottom and sand with algae and Thalassia ( Brattegard, 1969; Ortiz & Lalana, 1993). Additional published records from all around the Caribbean await reconsideration in the light of the present data.

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 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.

FIGURE 9. Parvimysis nuda sp. nov. from the Bahamas, holotype adult male with body length 2.1 mm (A, B, O), paratypes males 2.5 mm (C, E, F, M), 2.3 mm (G, J, L), another male 2.3 mm (K), and female 2.6 mm (D, H, N, P, Q); 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 scutellum paracaudale, lateral; Q, telson.