Metaprotella macoranicus, Momtazi, Farzaneh & Sari, Alireza, 2013

Momtazi, Farzaneh & Sari, Alireza, 2013, Intertidal caprellids (Crustacea: Amphipoda) of the Persian Gulf and the Gulf of Oman, with description of three new species, Zootaxa 3717 (2), pp. 195-223 : 198-204

Metaprotella macoranicus sp. nov.

( Figs 2–5 )

Material examined. ZUTC Amph. 2405, 11 males, four females, Loc 1 (Tiss, 25°21'21"N, 60°36'15"E), June 2011; and ZUTC Amph. 2420, one male, one female, Loc 40 ( Qeshm Island, 26°41'25"N, 55°56'4"E), February 2011.

Description. Holotype ♂. (ZUTC Amph. 2418, Tiss harbor 25°21'21"N, 60°36'15"E). Total length, 7.36 mm.

Lateral view ( Fig 2 ). Head, 0.4 mm, and pereonite 1, 0.21 mm; head and pereonite 1 fused, with marked suture between head and pereonite 1; head with a pair of small antero-dorsally curved projections and subtriangular lateral projection below the eye; eye large, distinctive. Pereonite 2, 1.15 mm with a pair of anteriorly curved mid-dorsal projections, an unpaired dorso-distal projection, an anterior lateral projection and subtriangular lateral projection below the insertion of second gnathopod. Pereonite 3, 1.7 mm with a trace of one pair mid-dorsal projections and with a dorso-distal projection posteriorly orientated. Pereonite 4 longest, 1.8 mm. Pereonite 5, 1.4 mm. Pereonites 6 and 7 completely fused, 0.5 mm.

Gill 3 ( Fig. 2 ) Length 0.37× pereonite 3, oval. Gill 4 ( Fig. 2 ) length 0.3× pereonite 4, oval, smaller than gill 3.

Mouthparts ( Fig. 3 ): Upper lip ( Fig. 3 UL) notched, wider than long, with small setae on anterior surface. Lower lip ( Fig. 3 LL) well developed, finely setose on inner lobes and outer lobes. Left Mandible ( Fig. 3 LMd); incisor with 5 teeth followed by lacinia mobilis with 5 teeth and 3 accessory setae; molar well developed, truncate; palp 3 articulate; article 2 with 6 simple setae; article 3 with setal formula 1+10+1, several setules along terminal margin and an antero-distal projection. Right mandible ( Fig. 3 RMd); incisor with 5 teeth and lacinia mobilis with 5 teeth and 2 accessory setae; molar well developed with flake; palp 3 articulate; article 2 with 5 setae; setal formula 1+10+1 on article 3. Maxilla 1 ( Fig. 3 Mx1) outer plate with 7 stout apical setal-teeth; palp biarticulate; article 2, with 4 triangular projections at distal margin and armed with 3 robust setae, 2 slender setae, 3 facial setae and some fine setae on inner margin. Maxilla 2 ( Fig. 3 Mx2); inner plate with 4 apical, one sub apical and 3 medial setae; outer plate with 8 apical setae and 2 subapical setae. Maxilliped ( Fig. 3 Mxp) inner plate subrectangular with 1 stout tooth, 2 simple setae and 2 plumose setae apically; outer plate 2× the length of inner plate with 1 plumose setae apically; inner margin with many blade-like setae and 2 setae medially; palp 4-articulated; article 2 longest and setose on inner margin; article 3 with a large triangular distal projection, 8 setae on inner margin and 1 seta on outer margin; palp dactylus falcate, with row of setules at inner and outer margins, and one proximal seta on outer margin.

Antennae ( Fig. 2 ). Antennae 1 ( Fig. 2 A1) about 0.6× body length; peduncular article 2 about 2.2× longer than article 1; article 2 longest, 1.5× longer than article 3; flagellum with more than 11 articles, proximal article composed of 3 articles. Antenna 2 ( Fig. 2 A2) slender, flagellum with 2 articles.

Gnathopods ( Fig. 2 ). Gnathopod 1 ( Fig. 2 Gn1 and Fig. 4 Gn1), basis length subequal to propodus with carina; ischium with dorsal carina; merus and carpus combined; carpus subtriangular and setose posterodistally; propodus subtriangular, longer than wide with 3 rows of submarginal setae, palm with 1 robust proximal seta, serrated along 3/4 of palm and with some fine setae; dactylus slightly curved distally, inner margin with serratiformed teeth. Gnathopod 2 ( Fig. 2 Gn2), basis 0.62× length of pereonite 2, with 2 fine distal setae and an acute anterodistal projection; carpus triangular; propodus enlarged, subovate and subequal in length to basis, outer margin with one medial seta and one distal seta; palm convex, proximal projection with 1 robust seta, mid-palmar projection oriented distally provided by 3 setae followed by a deep sinus and a well-developed distal shelf with 2 projections, distal sinus small, palm with serratiform teeth between proximal grasping spine and mid-palmar projection; dactylus falcate, with several fine setae.

Pereopods ( Fig. 4 ). Pereopod 3 ( Fig. 4 P3), slender, 0.1× pereonite 3, 1-articulated with 4 distal setae. Pereopod 4 ( Fig. 4 P4), slender, 0.1× pereonite 4, 1 articulate with 4 distal setae. Pereopod 5 ( Fig. 4 P5) well developed propodus longer than carpus with a pair of grasping spines near proximal end of palm, dactylus falcate with several fine setae along inner and outer margins. Pereopods 6 and 7 ( Fig. 4 P6–7), similar in shape but pereopod 7 larger than 6.

Abdomen ( Fig. 2 Ab), with one pair of appendages, a pair of lateral lobes and a single dorsal lob. Appendages 1-articulated with 4 setae along outer margin and two medial setae, tuff of minute setae and 3 longer seta at distal margin, 5 seta between penes and appendages. Dorsal lobe with a pair of plumose setae and one fine seta on dorsal surface.

Allotype (♀). (ZUTC Amph. 2419, Tiss harbor 25°21'21"N, 60°36'15"E). Total length, 5.27 mm.

Lateral view ( Fig. 5 ): Head length 0.35 mm and pereonite 1, 0.15 mm; head and pereonite 1 fused, with a markedly concaved area between head and pereonite 1. Head with a pair of antero-dorsally curved projections, subtriangular lateral projection below eye; eye large, distinctive; pereonite 2, 0.97 mm with a pair of anteriorly curved mid-dorsal projection, an unpaired dorso-distal projection, a small knobbed-like anterio-lateral projection and a subtriangular projection at base of second gnathopod; pereonite 3, 1 mm smooth; pereonite 4, 0.9 mm; pereonite 5, 1.20 mm, longest; pereonites 6 and 7 completely fused, 0.7 mm.

Gill 3 length 0.4× of pereonite 3, oval. Gill 4, 0.2× of pereonite 4, oval.

Mouthparts same as males. Antennae ( Fig. 5 ). Antenna 1 ( Fig. 5 A1), 0.7× body length; peduncular article 1 shortest; article 2 longest, 2.65× longer than article 1; article 3, 1.5× longer than article 1; flagellum with 11 articles. Antenna 2 ( Fig. 5 A2), slender, about 0.6× the length of antenna 1; flagellum with 2 articles.

Gnathopods ( Fig. 5 ). Gnathopod 1 ( Fig. 5 Gn1), basis longer than propodus, merus and carpus combined; carpus subtriangular, setose postero-distally; propodus subtriangular, longer than wide, palm with serratiform teeth along entire margin and a strong proximal spine; dactylus slightly curved distally, inner margin with serratiformed teeth. Gnathopod 2 ( Fig. 5 Gn2), basis subequal to propodus, scarcely setose, with an antero-distal projection with single seta; carpus triangular; propodus enlarged, and subovate; palm with three slightly distal projection, setose along entire margin, proximal projection with 1 robust seta; dactylus falcate, fitting on palm.

Pereopods ( Fig. 5 ). Pereopod 3 ( Fig. 5 P3), slender, 0.3× pereonite 3, 0.7× gill length, 1 articulate, with 5 distal setae and 1 lateral seta; oostegite 3 length 1.0× width, setose along entire margin. Pereopod 4 ( Fig. 5 P4) slender, 0.14× of pereonite 4, 0.6× gill length, 1 articulate with 4 distal setae; oostegite 4 length 0.7× width with 11 setae on anterior margin. Pereopods 5, 6 and 7 ( Fig. 5 ) similar, becoming more robust progressively.

Abdomen ( Fig. 5 Ab), a pair of lateral lobes and a single dorsal lobe. Dorsal lobe with 2 apical plumose setae and 4 lateral simple setae.

Remarks. Generic characters of Metaprotella was reviewed by Takeuchi & Lowry (2007) based on newly collected material of M. haswelliana (Mayer, 1882) , from Western Australia.

The new species, Metaprotella macoranicus , is a new member of M. sandalensis complex that was previously supposed to have a wide distribution in the Indo-West Pacific region. Recently, Lim & Takeuchi (2012) redescribed M. sandalensis and restricted the geographical distribution of this species. They introduced four characteristics for this species that include: 1) vestigial suture between head and pereonite 1; 2) antenna 1, 0.6 to 0.8× body length; 3) peduncle article 3 longer than article 2 in antenna 1; and 4) pereonite 4 longest among all body somites. Therefore, they excluded materials that previously recorded by Utinomi (1973), Arimoto (1976) and Guerra-García (2003a; 2004b) as M. sandalensis . Lim and Takeuchi (2012) also stated that material belonging to the M. sandalensis of Guerra-García (2003b, 2004a, 2006), Krapp-Schickel & Guerra-García (2005), and Guerra- García & Lowry (2009) was under debate.

Based on Lim & Takeuchi (2012) criteria, M. macoranicus differs from M. sandalensis in having a well defined suture between head and pereonite 1 and second peduncle article as the largest ones of the first antenna. In addition, in M. macoranicus the body projections were unique compared to other records of M. sandalensis ; middorsal projections of pereonite 3 are completely absent in females and reduced as a pair of small tubercles in males; also dorso-distal projection was oriented backward. Other specific characters of M. macoranicus are the setal formula as 1+10+1 and the setal arrangement in abdominal appendages composed of a tuft and three long setae. The sub-triangular projection at the base of second gnathopod was recorded only by Laubitz (1991) in Ceylon material.

The comparison between Iranian samples and other questionable records of M. sandalensis is documented in Table 2 . But, tuft setae on abdominal appendages, clear suture between head and pereonite 1, special projection arrangement in pereonite 3 and the presence of subtriangular projection at the base of second male gnathopod are the major differences. Some of excluded materials by Lim & Takeuchi (2012) from M. sandalensis show tuft setae in abdominal appendage (see; Utinomi 1973; Arimoto 1976; Guerra-García 2004b), but existing long and tuft setae in M. macoranicus previously was not recorded.

Distribution. In the present study, M. macoranicus was collected from intertidal rocky shores at two localities: Tiss harbor and the Qeshm Island. The distribution of M. macoranicus was restricted to east coast of Qeshm Island and there was no record along the west coast of the Persian Gulf.

Etymology. The term of macoranicus refers to Macoran, the larger area where the sampling location, Tiss harbor, is located.

Figures

FIGURE 2. Metaprotella macoranicus sp. nov. 7.36 mm. Holotype ZUTC Amph. 2418, Tiss. Scale a = 0.5 mm and b = 0.1 mm.

FIGURE 3. Metaprotella macoranicus sp. nov. Holotype ZUTC Amph. 2418, Tiss. Scale a = 0. 1 mm.

FIGURE 4. Metaprotella macoranicus sp. nov. Holotype ZUTC Amph. 2418, Tiss. Scale a = 0.5 mm and b = 0.1 mm.

FIGURE 5. Metaprotella macoranicus sp. nov. Allotype ZUTC Amph. 2419, Tiss. 5.27 mm Scale a = 0.5 mm and b = 0.1 mm.