Melita davilae, Ortiz, Manuel & Winfield, Ignacio, 2016

Ortiz, Manuel & Winfield, Ignacio, 2016, A new species of the genus Melita (Amphipoda, Hadzioidea, Melitidae) from anchialine pool on the Cozumel Island, NE Caribbean Sea, Zootaxa 4137 (1), pp. 73-84 : 74-83

publication ID	https://doi.org/ 10.11646/zootaxa.4137.1.5
publication LSID	lsid:zoobank.org:pub:5F2667C8-E937-424C-8A0A-EABB7E7CCFD7
DOI	https://doi.org/10.5281/zenodo.5664397
persistent identifier	https://treatment.plazi.org/id/9D0E8782-D422-FFFE-FF5A-FBA3BBF172BB
treatment provided by	Plazi
scientific name	Melita davilae
status	sp. nov.

Treatment

Melita davilae View in CoL sp. nov.

( Figures 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 )

Type material. Holotype: male 6.7 mm; collected from Cenote Aerolito; Cozumel Island, Quintana Roo, Mexico; 1.5 m depth; 25 June 2012 ( CNCR –30813). Paratype: ovigerous female; 4.9 mm, collected and deposited in the same collection as the holotype ( CNCR –30814).

Diagnosis. Antenna 1 article 2, 1.3x longer than one; accessory flagellum 4–articulate, distal article minute; primary flagellum 1.3x longer than peduncle; antenna 2 extending beyond peduncle of antenna 1; 0.7x as long as antenna 1; article 4 as long as 5; flagellum 7–articulate; eyes well developed, almost rounded; mandible palp article 2, 0.7x as long as 3; gnathopod 1 article 5, with a tuff of long setae on anterodistal angle, and seven tuffs of long and curved backward setae, ventrally; ventral and palmar margins of gnathopod 2 covered with long setae, lower half of inner palm slightly depressed; with very short facial setae; coxa 4 forming small posterior lobe; urosome segment 1, posterodorsal margin without medial process; urosome segment 2, posterior margin with two robust setae on right side, and one on left, in both sexes; uropods 1–2 peduncle with interramal spine well developed, at least 0.3x as long as rami; longer ramus on uropod 3, 2–articulate, scale with one robust seta. Female coxa 6 without lateral ridge at base of hook; anteroventral angle without stridulating ridges on anteroventral process; gnathopods 1–2 article 5 ventral margin and article 6, covered with long setae; longer ramus on uropod 3 uni– articulate; scale with 2 robust setae.

Description. Holotype male. Body ( Fig. 1 View FIGURE 1 A), almost smooth; without dorsal spine on urosome 1, urosome 2 with dorsal robust setae. Head ( Fig. 1 View FIGURE 1 A, B), as long as pereonal segments 1–2 combined; cephalic lobe rounded; cephalic notch present; eyes well developed, subrounded.

Antenna 1 ( Fig. 1 View FIGURE 1 C), article 2, 1.3x longer than one; accessory flagellum 4–articulate, distal article minute; flagellum 1.3x longer than peduncle.

Antenna 2 ( Fig. 1 View FIGURE 1 D), extending beyond peduncle of antenna 1, 0.7x as long as antenna 1; gland cone visible in lateral view; article 4 as long as 5; flagellum 7–articulate.

Mouthparts: upper lip ( Fig. 2 View FIGURE 2 A), rounded apically, covered with few short setae. Lower lip ( Fig. 2 View FIGURE 2 B), inner lobe well developed; outer lobe densely setose on medial margins, truncate robust setae on inner margin. Mandibles ( Fig. 2 View FIGURE 2 C, D), incisors with one small and three big teeth, the distal one the largest; lacinia mobilis with three teeth, 5–6 accessory pectinate setae; palp article 2 slightly curved, 3 D2 setae on inner margin, article 3, 1.5x longer than 2, covered with 3 B3 facial setae settled in line, 2D3 and 3E3 setae. Maxilliped ( Fig. 2 View FIGURE 2 E), inner lobe 0.8x narrower than outer, nine long distal setae; outer lobe with six robust setae on distal inner margin, six distally; palp article 2 surpassing tip of outer lobe, article 3 widest distally; dactylus with nail. Maxilla 1 ( Fig. 3 View FIGURE 3 A), outer lobe with nine bifid distal setae; palp 2–articulate, article 2 with 10 distal setae, and three very narrow subdistally; 3x longer than one, widest subdistally; inner lobe with eight distal setae. Maxilla 2 ( Fig. 3 View FIGURE 3 B), outer lobe longer than inner, covered distally with eight setae; inner lobe with six distal long setae, nine long and two short robust setae on distal half of inner margin.

Gnathopod 1 ( Fig. 3 View FIGURE 3 C), coxa 1 subquadrangular, as long as wide, ventral margin with 12 short and long setae; ischium with a tuft of long setae on distal inner half, and one setae at midway in outer margin; ischium with three distal setae; merus forming small posterior lobe, with margin almost covered with very short setae, and a tuft of long setae on tip; carpus with seven equidistant tufts of 3–6 setae, a tuft of 6–7 long anterodistal setae; propodus 0.7x as long as carpus, palm very complex, posterior third of palmar border armed with a row of six robust and short setae, distal anterior half of propodus with long setae; dactylus as long as palmar border.

Gnathopod 2 ( Figs. 3 View FIGURE 3 D, 4A), coxa 2 quadrangular, 1.5x longer than wide, ventral margin covered with eight long and short setae; anterior margin of basis covered with long setae, posterior margin with three long setae; ischium with one posterodistal seta; merus forming small posterior lobe, with four setae on tip; propodus 3.5x longer than carpus; carpus forming a discrete posterior lobe, with anterior and posterior setae; propodus ovoidal, very large; with six equidistant tufts of 2–3 setae on anterior margin; palm oblique slightly serrate; palmar angle poorly defined, armed with 14 robust short setae, posterior margin with six tufts of 2–6 long setae; dactylus strong and curved, devoid of setae. Inner face of propodus posterior half slightly depressed distally, and covered with short setae.

Pereopod 3 ( Fig. 4 View FIGURE 4 B), coxa quadrangular, with four long setae, ventrally; basis with long setae on posterior margin, curved, as long as merus and carpus combined; merus forming small anterodistal angle; carpus and propodus subequal in length; dactylus with nail.

Pereopod 4 ( Fig. 4 View FIGURE 4 C), coxa forming discrete posterior lobe; basis 1.2x longer than coxa, six long setae midway on posterior margin; merus 1.4x wider than carpus; carpus and propodus subequal in length; dactylus with nail.

Pereopod 5 ( Fig. 4 View FIGURE 4 D), coxa 0.3x shorter than coxa 4, forming posterior lobe; basis as wide as long, with serrated posterior margin, eight robust setae on anterior margin, forming a wide and rounded posterior lobe, 2.8x wider than merus; merus 0.8x longer than carpus; propodus 0.7x longer than carpus; dactylus curved, with nail.

Pereeopod 6 ( Fig. 4 View FIGURE 4 E), coxa similar to coxa 5; basis 0.7x as wide as long; 1.8x wider than merus; with serrate posterior margin; with seven robust setae on anterior margin; merus forming small posterodistal lobe; carpus 0.5x as wide as merus; propodus 1.3x as long as carpus; dactylus very curved, with nail.

Pereopod 7 ( Fig. 4 View FIGURE 4 F), coxa small and rounded, two setae on posterior margin; basis 2x wider than merus, 1.2x as long as wide, anterior margin with eight robust setae, posterior margin serrate; merus 1.2x longer than carpus, forming distal small lobe on anterior and posterior angles, anterior margin with four tuft of 2–4 setae, posterior margin with five setae; carpus with two tuft of setae on anterior margin and three on posterior ones; propodus with four tuft of setae on both margins, distal setae very long; dactylus very curved, devoid of nail.

Uropod 1 ( Fig. 5 View FIGURE 5 A), peduncle as long as rami, basofacial robust seta 0.3x as long as rami; inner ramus with four robust setae on inner margin, two on outer, and two long and one small distal setae; outer ramus with two robust setae on inner margin, two long and two short distal setae.

Uropod 2 ( Fig. 5 View FIGURE 5 B), peduncle 1.2x as long as rami, three robust setae on upper margin; interramal robust setae 0.3x as long as outer ramus; inner ramus with two robust setae on inner margin, three long and one small, distally; outer ramus with two robust setae on inner margin, and two long and three short distal setae.

Uropod 3 ( Fig. 5 View FIGURE 5 C), peduncle short, 0.5x as long as article 1 of inner ramus; outer ramus 2–articulate; article 1 with 3–4 robust setae and many long distal setae on each side, distal article short but evident, subequal in length than scale of inner ramus, with a tuft of long setae, distally; scale bearing one robust setae.

Epimeral plate 1 ( Fig. 1 View FIGURE 1 E), posterior margin devoid of setae; posteroventral corner almost right.

Epimeral plate 2 ( Fig. 1 View FIGURE 1 E), ventral margin with one seta; posteroventral corner rounded.

Epimeral plate 3 ( Fig. 1 View FIGURE 1 E), ventral margin with two setae; posteroventral corner almost right; posterior margin with three minute setae.

Urosome ( Fig. 1 View FIGURE 1 E); urosomite 1 dorsally smooth; urosomite 2 with two robust setae on right side, and one on left; urosomite 3 devoid of robust setae.

Telson ( Fig. 5 View FIGURE 5 D), lobes tapering till rounded tip, with 2–3 robust distal setae, and two on each inner margin, cleft 0.75x length.

Paratype female: smaller than male (4.9 mm). Coxa 6 ( Fig. 5 View FIGURE 5 E), without lateral ridge at base of hook; anteroventral angle rounded; without stridulating ridge.

Gnathopod 1 ( Fig. 6 View FIGURE 6 A), basis with long setae on outer and inner margins; carpus widest midway, ventral margin concave; propodus rectangular, shorter than in male, covered with long setae, dorsally.

Gnathopod 2 ( Fig. 6 View FIGURE 6 B), basis with long setae on posterior margin, almost as long as carpus and propodus combined; carpus with tuft of long setae, increasing in length forward; propodus shorter than in male; palmar margin with eight short robust setae; oostegite as long as basis.

Telson ( Fig. 6 View FIGURE 6 C), lobes similar than those of male, three setae on distal margin, one on inner margins, cleft till base.

Uropod 3 ( Fig. 6 View FIGURE 6 D), peduncle short, 0.3x as long as outer ramus; outer ramus with one article; outer ramus with 4–5 robust setae on each side, with long setae on distal half; scale bearing two robust setae. Urosomites 1–3 ( Fig. 6 View FIGURE 6 E), similar than in male.

Epimeral plate 1 without setae on ventral margin; e pimeral plate 2 with three setae; epimeral plate 3 with two setae ( Fig. 1 View FIGURE 1 E).

Etymology. This new species is named in honor to Patricia Dávila Aranda, Director of Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, México.

Remarks. The new species Melita davilae belongs to the “atypical group” ( Jarret & Bousfield 1996), to the first group according with Labay´s classification ( Labay 2003), and to the group B2 of Krapp–Schickel & Sket´s classification(Krapp– Schickel & Sket 2015).

The main morphological differences between Melita davilae sp. nov., and Melita species previously documented to the Gulf of Mexico and the Caribbean Sea are given in table 1.

Melita davilae sp. nov., and M. stocki are the most morphological closed species, but the former can be distinguished by long tuffs of setae on both gnathopods. Melita davilae sp. nov., differs of these species (excluding M. dentata and M. longisetosa), by having four articles in the accessory flagellum; and from M. planaterga by having coxa 6 devoid of ridge at base of hook. Also, from M. intermedia and M. nitida by having no stridulating ridge on coxa 6. Melita davilae sp. nov., can be easily distinguished from all those Melita species, by bearing in middorsal urosomite 2, one seta on left and two on right sides, and ventral setae on the epimeral plates 1–3 are 0, 1, and 2, respectively. All morphological differences are summarized in table 1.

Including the new species described in this paper, the genus Melita increases to 84 the number of species documented worldwide, and 11 species for the Gulf of Mexico and the Caribbean Sea (Intra-American Sea): M. dentate Kroyer, 1842 (Gulf of Mexico, Caribbean Sea); M. elongata Sheridan, 1980 (Gulf of Mexico); M. guanaense Ortiz, García-Debrás & Lalana, 2002 (NW Cuba); M. intermedia Sheridan, 1980 (Gulf of Mexico); M. leiotelson Vonk, 1989 (Caribbean Sea) ; M. longisetosa Sheridan, 1980 (Gulf of Mexico, Caribbean Sea); M. nitida Smith, 1873 (Gulf of Mexico, Caribbean Sea); M. persona Karaman, 1987 ( Venezuela); M. planaterga Kunkel, 1910 ( Bermudas, Gulf of Mexico, Venezuela) and M. stocki Karaman, 1987 ( Bermudas, Caribbean Sea), ( Ortiz et al. 2007; Le Croy et al. 2009; Martin et al. 2013; Paz– Ríos & Ardisson 2013) and M. davilae n. sp. (NE Caribbean Sea or Mexican Caribbean).