Cubanomysis manuelortizi, Hendrickx & Hernández-Payán & Gómez-Gutierrez, 2023

Hendrickx, Michel E., Hernández-Payán, José Carlos & Gómez-Gutierrez, Jaime, 2023, On a small collection of mysids (Crustacea, Peracarida, Mysida) from the southern Gulf of California, western Mexico, with the description of new species of Mysidium and Cubanomysis, Zootaxa 5360 (2), pp. 194-218 : 207-216

Cubanomysis manuelortizi sp. nov. Hendrickx & Hernández-Payán

( Figs. 8‒11)

Material examined. Holotype, male (CL 1.35 mm, TL 3.14 mm), April 18, 2016, Los Morros (23°27’N, 109°25’W), Cabo Pulmo National Park, Southern Baja California, Mexico, about 5 m depth (ICML-EMU-12984) . Paratype, male (CL 1.23 mm, TL 2.73 mm), same sample, same locality (ICML-EMU-13275). Allotype, female (CL 1.42 mm; TL 4.43 mm), May 7, 2017, same locality, about 5 m depth (ICML-EMU-13458) .

Diagnosis. Third article of antennular peduncle with a small process in middle of distal margin, tipped with a small, slightly curved spine. Mandibular palp median article widening in distal third, 4 simple setae on outer margin, inner margin with 14 regularly set, long, setae; terminal article about 0.5 length of median article, with 6 long, simple setae, 7 barbed setae near apex, and one terminal, longer, curved, barbed seta. Maxillula outer lobe with 8 robust, apical setae. Maxilla distal segment of endopodite with 15 setae, distal four much more robust; two endites armed with 17 long, marginal setae each. Distal seta on the exopod of the male pleopod 4 longer than the rest of the exopod, armed with a single series of spinules covering less than 0.5 of the seta length. Uropodal exopod 7.7 times as long as wide. Male uropodal endopod with 19 robust setae, extending close to the distal tip of the endopod. Telson 1.2 times as long as wide, distally slender, minimum width less than 0.5 telson maximum width. Cleft in the posterior margin of telson shallow, telson of males with 3 robust setae in each lateral lobes and 8 in the cleft (14 in total), setae similar in size.

Description based on the male holotype (ICML-EMU-12984). Carapace elongated, slightly produced anteriorly in a small triangular, blunt process ( Fig. 8A).

Eyes ( Fig. 8A) large, semi-oval, cornea wider than long.

Antennular peduncle ( Fig. 8B) short; article 1 rectangular, longer than articles 2 and 3; article 2 distinctly smaller than other two; article 3 sub-rectangular, almost as wide as long, a small process in middle of distal margin, with a small, slightly curved spine at apex ( Fig. 8B); processus masculinus ( Fig. 8C) elongate, with long setae and a series of small, marginal spiny granules.

Antennal peduncle ( Fig. 8D) shorter than scale; article 1 short, articles 2 and 3 rectangular, almost the same length, article 2 slightly more robust than third. Antennal scale ( Fig. 8D) approximately 6 times as long as broad, slightly wider near its base, extending beyond the distal edge of the antennal peduncle by almost 0.5 its length, 2- articulated, distal suture well marked, proximal article approximately 3.5 times the length of the distal article; scale extending beyond the distal margin of antennular article 3 by about 0.5 the length of its distal article ( Fig. 8A).

Mandibular palp ( Fig. 8E) with proximal article short, naked; median article widening in distal third, long, 4 simple setae on outer margin, inner margin with 14 regularly set, long, setae; terminal article about 0.5 times length of median article, with 6 long, simple setae, 7 barbed setae near apex, and one terminal, longer, curved, barbed seta.

Maxillula ( Fig. 8F) outer lobe with 8 robust, apical setae; inner lobe with 2 long, robust apical setae (one broken), unbroken seta with some distal spinules.

Maxilla ( Fig. 8G) with sub-triangular distal segment of endopodite longer than wide, distal margin forming a sharp angle, with 15 setae, distal 4 much more robust; 2 endites armed with 17 long, marginal setae each; proximal-most margin with 3 long, robust marginal setae; exopod longer than wide, armed with 5 long, robust, marginal simple setae increasing in length distally.

Thoracopods missing.

Pleopods 2‒5 ( Fig. 9A‒D) biramous (pleopod 1 missing), well developed, endopods slightly shorter than exopods (endopod of pleopod 4 missing), proximal lobe (pseudo-branchiae) armed with 5 short, simple setae; exopod of fourth pair ( Fig. 9C) with one very slender, terminal long seta, about 1.4 times the length of the rest of exopod, armed on one side with spinules covering less than 0.5 times seta length; all exopods and endopods covered with long, plumose setae on both margins.

Uropods ( Fig. 8H) exopod almost twice as long as telson, 8 times longer than wide; endopod 1/4 shorter than exopod, wider near its base, with well marked statocyst, inner ventral margin armed with 19 robust, well separated setae, increasing slightly in size toward the tip.

Telson ( Fig. 8I) short, pear-shaped, 1.2 times as long as wide, lateral margins unarmed, strongly constricted posteriorly, maximum (anterior) width about 2.3 times minimum (posterior) width, distal cleft shallow, semicircular, distal margin armed with 14 robust setae, almost of similar size.

Male paratype ( Fig. 10) (ICML-EMU-13275). Similar to the holotype, except for the first article of the antennula peduncle ( Fig. 10B) which is slightly shorter, and the processus masculinus which is also slightly different ( Fig. 10C) and features a slightly longer series of small spiny tubercles.

Female allotype ( Fig. 11A‒E) (ICML-EMU-13458). Similar to male except for: the proportionally, slightly longer peduncle of the antenna; the proportionally longer and slender articles 1 and 3 of the antennular peduncle; the presence of 19 setae on the telson posterior margin; and 28 robust setae on uropodal endopod.

Type locality. Los Morros (23°27’N, 109°25’W), Cabo Pulmo National Park , Southern Baja California, Mexico. Only known locality to date .

Etymology. The new species is named after our friend and colleague Manuel Ortiz Touzet (as a combination of his name, Manuel, and first surname, Ortiz), in recognition for his long career dedicated to the study of Cuban crustaceans, in particular Peracarida, and his extensive contribution to our knowledge of American mysids.

Remarks. In the case of Cubanomysis jimenesi , the type-species of the genus by monotypy ( Băcescu 1968), both the original description and illustrations by Băcescu (1968) and the figures provided by Brattegard (1973) are well detailed and of high quality, and partly included herein (see Figs. 12, 13). Cubanomysis jimenesi is also briefly characterized by Ortiz & Lalana (2017) and Ortiz et al. (2012) (species list and keys). Cubanomysis mysteriosa , the second species described for the genus, has apparently not been reported since its description based on material from southern California (1 male holotype, USNM 184074; 2 males and 2 females, paratypes, USNM 184075). Consequently, the only illustrations available are those provided by Gleye (1982) (see Fig. 14). Although these are rather poor in quality, they allow for a comparison with our material.

Compared to males of C. jimenesi , as illustrated by Brattegard (1973: fig. 6B), the unique male specimen of Cubanomysis manuelortizi sp. nov. presents a much shorter antennal peduncle ( Figs. 8D, 10D), with the distal article reaching 2/3 of the scale proximal article length vs. reaching the tip of the proximal article in C. jimenesi ( Fig. 13B). However, in the original description ( Băcescu 1968) the antennular peduncle (the sex of the specimen is not indicated) is shorter ( Fig. 12B), similar to the peduncle of C. manuelortizi sp. nov.: “... A2 a la base beaucoup plus courte que l’écaille” (the antennula has its base much shorter than the scale) ( Băcescu 1968: 233). Compared to C. manuelortizi sp. nov. ( Figs. 8B, 10B), the male antennal peduncle is about the same length as in C. mysteriosa ( Fig. 14A). The antennal scale is weakly surpassing the antennal peduncle in C. jimenesi whereas it extends more clearly beyond the peduncle in the two Pacific species.

The male antennula of C. manuelortizi sp. nov. ( Figs. 8B, 10B) is very similar to the other two known species, although in the case of C. mysteriosa ( Fig. 14A) comparison is rather difficult due to the bad quality of the original drawing. In C. manuelortizi sp. nov., it clearly matches the male antennula of C. jimenesi as illustrated by Băcescu (1968) and Brattegard (1973) (see Figs. 12A, 13A), with article 1 rectangular, article 2 less than 0.5 article 1 length, and article 3 squarish, about as long as article 1 but wider. In C. jimenesi , however, as in C. mysteriosa , the third article of the antennular peduncle does not feature a small process tipped by a curved spine at apex of the article, as seen in C. manuelortizi sp. nov. In C. manuelortizi sp. nov. the antennal scale extends beyond the distal margin of antennular article 3 by about 0.5 the length of its distal article ( Fig. 8A). Comparatively, in C. jimenesi (original description) the antennal scale comes close to the distal margin of article 3 of the antennular peduncle but does not overreach it, while in C. mysteriosa the antennal scale overeaches the antennular peduncle by about the combined length of the antennula 2 distal articles.

The processus masculinus with tuft of long setae is also visible in illustrations of the three species ( Figs. 8C, 10C, 12A, 13A, 14A), but the lack of details does not allow for a clear comparison with C. manuelortizi sp. nov. In C. manuelortizi sp. nov., there is a series of small, marginal spiny granules on the distal part of the processus masculinus, not illustrated or reported in the two other species.

The maxillae of the three species are similar, but setae on endites of C. jimenesi are less numerous and clearly more robust ( Fig. 12C) than in C. manuelortizi sp. nov. ( Fig. 8G); the marginal robust setae on the exopod of C. mysteriosa ( Fig. 14C) also appear much more robust than in C. manuelortizi sp. nov. ( Fig. 8G).

In C. manuelortizi sp. nov. the distal seta on the exopod of the male pleopod 4 ( Fig. 9C) is longer, 1.4 times the length of the rest of exopod, and armed with a single series of spinules covering less than 0.5 the seta length. Comparatively, according to Băcescu (1968), in C. jimenesi this terminal seta is slightly shorter than the rest of the exopod, also with spinules on one margin, but covering only about 1/3 the length of the seta (see Fig. 12D). In his illustration of C. jimenesi , however, Brattegard (1973) reported a terminal seta much longer than the rest of the exopod and series of spinules on both sides, on less than 1/5 the length of the seta (see Fig. 13C). In C. mysteriosa , the terminal seta is about as long as the length of the rest of the exopod and also features a series of distal spinules on both margins ( Fig. 14E).

The shape of the telson in C. manuelortizi sp. nov. ( Fig. 8I, 10F) and C. jimenesi (see Figs. 12F, 13E) is similar, with a strong constriction of the distal part, although the posterior portion is slightly narrower in the figure provided by Băcescu (1968) (see Fig. 12F). The cleft in the posterior margin of the telson, however, is much shallower in C. manuelortizi sp. nov. ( Fig. 8I, 10F) compared to C. jimenesi , which is deep and V-shaped. According to Băcescu (1968), males of C. jimenesi features 2 robust setae in each lateral lobe, and 10 setae in the cleft (6‒8 in females), 14 in total (10‒12 in females) (see Fig. 12F), vs. 3 in each lateral lobes and 8 in the cleft (14 in total) in C. manuelortizi sp. nov. ( Figs. 8I, 10F). Brattegard (1973: 19), however, provided a different arrangement of the telson setae: 2‒4 on each lobe and 4‒6 in the sinus (cleft), making a total of 8 to 14 setae. The series of robust setae on the uropodal endopod is more extended (19 spines) and reaches closer to the endopod tip in C. manuelortizi sp. nov. ( Figs. 8H, 10E) than in C. jimenesi (10‒11 robust setae, the series ending further away from the tip of the endopod).

The telson is distally slender in C. manuelortizi sp. nov. ( Figs. 8I, 10F), i.e., less than 0.5 times the telson maximum width, vs. more than 0.5 times the telson maximum width in C. mysteriosa (see Fig. 14G); the posterior margin also has a shallower cleft in C. manuelortizi sp. nov. compared to C. mysteriosa , and bears 14, robust setae vs. 16‒24 closely set setae in C. mysteriosa ; the series of robust setae on the uropodal endopods is 19 in C. manuelortizi sp. nov., and these setae extend close to the distal tip of the endopod ( Figs. 8H, 10E), vs. only 10 robust setae in C. mysteriosa , the latter extending slightly beyond the proximal half of the endopod (see Fig. 14F).

Based on illustrations provided by Gleye (1982), the uropodal exopod is proportionally shorter in C. mysteriosa (length = 6.1 times its width) (see Fig. 14F) than in C. manuelortizi sp. nov. (length = 7.7 times its width) ( Figs. 8H, 10E), and the relationship between exopod and endopod length is about 1.17 in C. mysteriosa vs. about 1.24 in C. manuelortizi sp. nov. In C. jimenesi the uropodal exopod length/wide relationship is 6.7 (intermediate between C. manuelortizi sp. nov. and C. mysteriosa ) and the exopod/endopod lengths relationship is 1.24, as in C. manuelortizi sp. nov.

The first two thoracopods of C. mysteriosa , as described by Gleye (1982: fig. 1f, 2a) are strikingly distinct from the “pereiopods” I and II illustrated by Băcescu (1968: fig. 1D, E) for C. jimenesi , the type species of the genus. The diagnosis of Cubanomysis by Băcescu (1968: 232), however, is not very clear in this respect. When additional material of C. manuelortizi sp. nov. is available, and fully compared with the other two known species, including the thoracopods, the diagnosis of Cubanomysis should be revisited.