Parhyalella penai, Schultheiss, Jorge Pérez - & Crespo, Julio E., 2008

Schultheiss, Jorge Pérez - & Crespo, Julio E., 2008, A new species of Parhyalella Kunkel, 1910 (Amphipoda, Talitroidea, Dogielinotidae) from the coast of Chile, Zootaxa 1724, pp. 61-68 : 62-68

publication ID	https://doi.org/ 10.5281/zenodo.181194
DOI	https://doi.org/10.5281/zenodo.6230593
persistent identifier	https://treatment.plazi.org/id/03C21A3E-FFD8-FFEB-FF54-2ACE3AD3FEEE
treatment provided by	Plazi
scientific name	Parhyalella penai
status	sp. nov.

Treatment

Parhyalella penai n. sp. ( Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Parhyalella sp. Andres, 1975: 85 –86; González, 1991a: p. 56; González, 1991b: 102 –103, fig. 7 Not Parhyalella ruffoi Lazo-Wasem & Gable, 2001: 31 –37, Figs. 23–27

Etymology: “ penai ” is derived from “Peña”. This species is dedicated to Luis E. Peña Guzmán, Chilean entomologist and naturalist (21.01.1921 - † 27.09.1995).

Type locality: La Herradura Bay (29º58’S; 71º22’W), IV Región, Chile.

Type material: male holotype MZUC 32707, 9.34 mm, carcass with appendages mounted on two slides; female allotype MZUC 32708, ovigerous, 6.06 mm, carcass with appendices mounted on two slides; male paratypes MZUC 32711, 8.88 mm, carcass with appendices mounted on two slides; male paratype MZUC 32712, 8.55 mm; male paratype MZUC 32713, 8.53; male paratype MZUC 32714, 8.62 mm; male paratype MZUC 32715, 7.71 mm; male paratype MZUC 32716, 8.44 mm and male paratype MZUC 32717, 8.49 mm, all from La Herradura Bay, Coquimbo, IV Región, 22 May 2005, col. J. Pérez-Schultheiss. Male paratype MZUC 32709, 8.10 mm; male paratype MZUC 32710, 10.08 mm and male paratype MZUC 32718, 8.88 mm, all from Río Sur, Maicolpué, X Región, 14 October 2001, col. J. Pérez-Schultheiss.

Additional material examined: La Herradura Bay, Coquimbo, IV Región, 22 May 2005, col. J. Pérez- Schultheiss, 27 males, MZUC 32722 and 11 females, MZUC 32720; Río Sur, Maicolpué, X Región, 14 October 2001, col. J. Pérez-Schultheiss, 61 males, MZUC 32721 and 78 females, MZUC 32719.

Diagnosis: Male. Eye medium-sized, oval, dark. Antenna 2, peduncle very stout, article 1 of flagellum 4– conjointed. Gnathopod 1, article 5 anterior margin with or without medial single setae; article 6, palm transverse, slightly concave; dactyl bifurcate. Gnathopod 2, article 6, hind margin rounded. Uropod 2 inner ramus, margin with row of single spines.

Description: Male holotype. Eye medium, oval, dark in alcohol-preserved specimen. Antenna 1 scarcely exceeds half of length of the article 5 of peduncle of antenna 2; flagellum with 13 articles ( Fig. 2 View FIGURE 2 , A1). Antenna 2 peduncle strongly inflated, article 5 distinctly longer than article 4; flagellum shorter than peduncle article 5, article 1 of flagellum 4–conjointed (but first conjoint seemingly bisegmented in posterior margin), combined length of remaining flagellar articles shorter than conjointed article ( Fig. 2 View FIGURE 2 , A2). Upper lip distal margin broadly convex, finely setose. Lower lip, outer lobes broad, distal and inner margins finely setose. Right mandible ( Fig. 1 View FIGURE 1 , rM) molar strong, triturative, inner margin with 3 plumose setae, lacinia mobilis simple, incisor with three stout distal teeth and three small lateral teeth (and one small, nearly vestigial proximal tooth). Left mandible ( Fig. 1 View FIGURE 1 , lM) similar to right, molar with plumose accessory setae, inner margin with two large and two small plumose setae, lacinia mobilis with 3 lateral teeth and 2 distal serrate teeth. Maxilla 1 inner plate with two stout plumose setae; outer plate with five serrate teeth (normally with 9 teeth, some teeth are lost in holotype), inner margin lightly setose near base of teeth. Maxilla 2 ( Fig. 2 View FIGURE 2 , M2), inner plate subequal in width and slightly shorter than outer plate, with row of plumose and simple setae along inner and distal margin, proximal plumose setae stout; outer plate with few small setae at outer distal corner, distal margin with subapical and apical row of setae. Maxilliped ( Fig. 2 View FIGURE 2 , Mp), inner plate distally with three stout teeth and some slightly longer simple and plumose setae, inner margin lined with plumose setae and fine facial setae; outer plate setose along distal and inner margin, apical setae stout; palp article 2 with broad setose inner lobe, article 3, inner margin with distal lobe; article 4 with long distal nail, not longer than apical setae. Coxal plates 1–4 with very small marginal setae in ventral margin, coxal plate 1 slightly produced anteriorly. Gnathopod 1 ( Fig. 3 View FIGURE 3 , Gn1), article 5 slightly longer than article 6; anterior margin with single marginal setae and distal cluster of apical setae (similar to P. batesoni ); article 6, palm transverse, slightly concave, posterior corner rounded, cover with minute tubercles and with three spines; dactyl bifurcate. Gnathopod 2 ( Fig. 3 View FIGURE 3 , Gn2), article 6 width 70% of length, palm nearly straight but slightly concave near posterior corner, spinose and setose, with two stout spines at posterior corner, hind margin with three setal groups; dactyl, posterior margin with row of small setules. Pereopods 3 ( Fig. 3 View FIGURE 3 , P3) and 4 ( Fig. 4 View FIGURE 4 , P4) similar, 3 slightly longer, article 2 posterior margin with few setae, article 5 and 6, posterior margin spinose. Pereopods 5–7 sequentially longer. Pereopod 5 ( Fig. 4 View FIGURE 4 , P5), article 2 and 4 with distinct posterior lobe, distal part of article 2 posterior lobe as long as article 3, article 4 anterior margin with two medial spine clusters, article 5 shorter than article 4. Pereopod 6 ( Fig. 5 View FIGURE 5 , P6) and 7 ( Fig. 4 View FIGURE 4 , P7) similar, articles 2 and 4 with distinct posterior lobe, posterior margin of articles 5 and 6 lacking spines. Uropod 2 ( Fig. 1 View FIGURE 1 , U2), inner ramus, margin with row of single spines. Uropod 3 peduncle two times as long as ramus, with two distal spines, ramus distally with two short spines and one setae. Telson, distal margin forming blunt point, distal third of telson with some small simple setae and spinules.

Female allotype: Eye similar to male. Antenna 1 extending well beyond peduncle of antenna 2, flagellum without aesthetascs and with 10 articles; antenna 2 flagellum of 10 articles. Gnathopod 1 ( Fig. 5 View FIGURE 5 , aGn1), article 6, anterior and posterior margins parallel; palm transverse, straight, nearly convex; hind margin of propodus with 5 setae; dactyl simple. Gnathopod 2 ( Fig. 5 View FIGURE 5 , aGn2), article 5 posterior lobe broad, extending below article 6; palm nearly straight; hind margin of propodus convex, slightly shorter than palm, with 3 setal groups.

Habitat: Specimens from Rio Sur were collected among floating algae in shallow waters. Specimens from La Herradura Bay were found among algal strandings on a sandy beach. These observations suggest that P. penai n. sp. normally inhabits subtidal algal beds, previously suggested by Lazo-Wasem and Gable (2001) as the habitat for other species of the genus. The species is a grazer feeding on a wide variety of macroalgae, such as Glossophora kunthii , Macrocystis integrifolia , Lessonia nigrescens, Condrachanthus chamissoi and Grateloupia doryphora (Macaya et al., 2005; Rothäusler et al., 2005)

Distribution: This species has been recorded from Coquimbo (29º56’S; 71º21’W), Region IV to San Vicente Bay (36º44’S; 73º09’W), Region VIII. The new material extends the range northward to Río Sur, Maicolpué (40º36’S; 73º44’W), Region X, Chile.

Remarks: The identification of species of Parhyalella is difficult, and only males can be determined with any certainty because female character distributions for all species are poorly known ( Lazo-Wasem and Gable, 2001).

Lazo-Wasem and Gable (2001) included Parhyalella sp. from Chile in the synonymy of P. r u f f o i but did not examine Chilean specimens. Some differences between P. r u f f o i and the figures of González (1991b) are present. Nevertheless, characters illustrated by González (1991b), such as bifurcate dactyl of gnathopod 1 and the peduncle of uropod 3 with two distal spines, suggest that these specimens are conspecific with P. penai n. sp.

P. penai n. sp. differs from P. ruffoi principally in the possession of a 4-conjointed article 1 of flagellum of antenna 2 (5-conjointed in P. ruffoi ), bifurcate gnathopod 1 dactyl (simple in P. ruffoi ) and in having the width of article 6, gnathopod 2 70% of the length (90% in P. r u f f o i). In addition, characters such as eye size and color (small to medium and faint red in P. r u f f o i) and the presence of two distal spines in the peduncle of uropod 3 (versus one in P. r u f f o i).

The new species is similar to P. kunkeli Lazo-Wasem and Gable, 2001 and P. barnardi Lazo-Wasem and Gable, 2001 . P. penai , differs in the form of the palm of gnathopod 1 (oblique, convex in P. kunkeli ), the presence of 2 distal spines in the peduncle of uropod 3 (4 in P. kunkeli , 3 in P. barnardi ) and the size of eye (large and with ocelli widely spaced in P. barnardi ). The bifurcate dactyl of gnathopod 1 distinguishes this species from P. batesoni , P. congoensis , P. barnardi , P. nisbetae and P. r u f f o i.

Some diagnostic characters used to differentiate Parhyalella species are variable in P. penai n. sp. as Lazo-Wasem and Gable (2001) report for P. pietschmanni . Medial setae on the anterior margin of the fifth article of male gnathopod 1 are present in the holotype similar to P. batesoni Lazo-Wasem and Gable, 2001 . In several specimens of the same locality (e. g. paratype MZUC 32711) these setae are absent without evidence of being broken off or otherwise lost. Also, the conjointed first article of the antenna 2 flagellum (males) appears variable, but probably for development defects, because most specimens have a 4-conjointed article. More analyses are needed of males and females of all species to solve these problems.

P. p e n a i n. sp. can be included in the following version of the key proposed by Lazo-Wasem and Gable (2001).

1. Gnathopod 2, article 6, posterior corner produced in largest males .............................................................. .................................................................................... Parhyalella nisbetae Lazo-Wasem and Gable, 2001

- Gnathopod 2, article 6, posterior corner rounded, not produced.................................................................2

2. Gnathopod 1, article 5, anterior margin with medial setae..........................................................................3

- Gnathopod 1, article 5, anterior margin bare...............................................................................................6

3. Gnathopod 1, article 5, anterior margin with one seta, palm transverse......................................................4

- Gnathopod 1, article 5, anterior margin with more than one seta, palm oblique.........................................5

4. Antenna 2, article 1 of flagellum 5-conjointed; gnathopod 1, article 7 simple; eyes large, oval, black........ .............................................................................................................. Parhyalella batesoni Kunkel, 1910

- Antenna 2, article 1 of flagellum 3-conjointed; gnathopod 1, article 7 bifurcate; eyes small, round, pale to dark ............................................................................................. Parhyalella whelpleyi (Shoemaker, 1933)

5. Gnathopod 1, article 5, anterior margin with two setae, article 7 bifurcate; antenna 2, article 1 of flagellum 5-conjointed; uropod 2, inner ramus with one group of double spines ......................................................... .............................................................................................. Parhyalella pietschmanni Schellenberg, 1938

- Gnathopod 1, article 5, anterior margin with four setae, article 7 simple; antenna 2, article 1 of flagellum 2-conjointed; uropod 2, inner ramus with single spines only .............. Parhyalella congoensis Ruffo, 1953

6. Gnathopod 1, palm concave.........................................................................................................................7

- Gnathopod 1, palm straight or convex.........................................................................................................8

7. Antenna 2, article 1 of flagellum 4-conjointed; eyes variable, not faded red to brown..............................9

- Antenna 2, article 1 of flagellum 5-conjointed; eyes large, oval, faded red to brown................................... ......................................................................................... Parhyalella ruffoi Lazo-Wasem and Gable, 2001

8. Antenna 2, article 1 of flagellum 4-conjointed; eyes medium, oval; gnathopod 1, palm oblique................. ...................................................................................... Parhyalella kunkeli Lazo-Wasem and Gable, 2001

- Antenna 2, article 1 of flagellum 5-conjointed; eyes small, round; gnathopod 1, palm transverse...............

....................................................................................... Parhyalella steelei Lazo-Wasem and Gable, 2001 9. Gnathopod 1, dactyl simple; uropod 2, inner ramus with two groups of two spines; eyes very large, oblong, golden, widely spaced ocelli ......................... Parhyalella barnardi Lazo-Wasem and Gable, 2001 - Gnathopod 1, dactyl bifurcate; uropod 2, inner ramus with row of single spines only; eyes medium, oval, dark ......................................................................................................................... Parhyalella penai n. sp.