Lafkenorchestia oyarzuni, Pérez-Schultheiss & Fernández & Ribeiro, 2024

Pérez-Schultheiss, Jorge, Fernández, Leonardo D. & Ribeiro, Felipe Bezerra, 2024, Two new genera of coastal Talitridae (Amphipoda: Senticaudata) from Chile, with the first record of Platorchestia Bousfield, 1982 in the southeastern Pacific coast, Zootaxa 5477 (2), pp. 195-218 : 208-213

Lafkenorchestia oyarzuni sp. nov.

( Figs. 1B , 8–11 )

http://zoobank.org/ urn:lsid:zoobank.org:act:D06BD29D-1241-4DAC-BBFE-43B380F342C8

Material examined: Male holotype (13.41 mm, MNHNCL AMP-15966): Manquemapu, Purranque, Osorno , Región de Los Lagos, -40.8904 -73.84912, 2019-10-16, Coll. J. Pérez-Schultheiss, under stones, Lliuco river estuary, next to the bridge, JP-436. 1 male paratype I (MNHNCL AMP-15967): Parque Pichimallay, San Juan de La Costa, Osorno , Región de Los Lagos, -40.60369 -73.75948, 2005-07-08, coll. J. Pérez-Schultheiss, under stones and rocks. 1 male paratype J (MNHNCL AMP-15968), 1 female paratype K (MNHNCL AMP-15969), 1 male paratype O (MNHNCL AMP-15970): same data as paratype I. 1 male paratype C (MNHNCL AMP-15971): Estuario Rio Lliuco, Manquemapu, Purranque , Osorno , Región de Los Lagos, -40.89037 -73.84945, 2018-01-31, Coll. J. Pérez-Schultheiss, between reeds and halophytes, under stones, JP-312. 1 male paratype D (MNHNCL AMP-15972), 1 female paratype E (MNHNCL AMP-15973), 1 female paratype F (SCBUCN-8188): same data as paratype C. 1 male paratype A ( MZUC-CCC 47921 ): Estuario Rio Lliuco, Manquemapu, Purranque , Osorno , Región de Los Lagos, -40.89037 -73.84945, 2018-11-30, coll. J. Pérez-Schultheiss, under stones, between low herbaceous vegetation, JP-394. 1 male paratype B (MNHNCL AMP-15975): same data as paratype A. 1 male paratype G (MNHNCL AMP-15976): Marismas Rio Quilo, Ancud, Chiloé , Región de Los Lagos, -41.87076 -73.98223, 2007-10-05, coll. J. Pérez-Schultheiss, U. Mosqueira & L. Muñoz, under wooden planks and stones, JP-8. 1 female paratype H ( MHNV-CBTI 0003 ): same data as paratype G. 1 male paratype L (MNHNCL AMP-15978): Pucatrihue, San Juan de la Costa, Osorno , Región de Los Lagos, -40.53901 -73.71459, 2005-05-01, coll. J. Pérez-Schultheiss, Under logs at the edge of the road, foot of the cliff, clear terrain. 1 male paratype M (SCBUCN-8189), 1 female paratype N ( MZUC-CCC 47922 ), 1 male paratype P ( MHNV-CBTI 0004 ): same data as paratype L. 1 male B (MNHNCL AMP-15981): Humedal de Carampangue , Arauco, Región del Biobío, -37.2358 -73.3031, 2017-11-20, coll. Cristina Coccia, Trampas pitfall, associated to Spartina . 9 males, 12 females (MNHNCL AMP-15982) : Parque Pichimallay, San Juan de La Costa, Osorno , Región de Los Lagos, -40.60369 -73.75948, 2005-07-08, coll. J. Pérez-Schultheiss, under stones and rocks, 402. 4 females (MNHNCL AMP-15983) : Triltril, Osorno, Región de Los Lagos, -40.61756 -73.75016, 2013-10-12, coll. J. Pérez-Schultheiss, Under logs, vega, tributary stream to Triltril river , 407. 1 female (MNHNCL AMP-15984) : same data as before, Cliff facing the sea, in a spring, under stones, between sediments, 417. 1 female (MNHNCL AMP-15985) : Playa Leucotón, Manquemapu, Purranque , Osorno , Región de Los Lagos, -40.89174 -73.85139, 2018-01-31, Coll. J. Pérez-Schultheiss, Under rocks, supratidal, among Transorchestia , JP-310. 7 males, 29 females (MNHNCL AMP-15986) : Estuario Rio Lliuco, Manquemapu, Purranque , Osorno , Región de Los Lagos, -40.8904 -73.84912, 2018-01-31, Coll. J. Pérez-Schultheiss, between reeds and halophytes, under stones, JP-312. 1 female (MNHNCL AMP-15987) : Manquemapu, Purranque, Osorno , Región de Los Lagos, - 40.88866 -73.85712, 2018-11-01, Coll. J. Pérez-Schultheiss & F. Urra, Interior decayed log, supratidal, JP-361. 2 males, 7 females (MNHNCL AMP-15988) : Estuario Rio Lliuco, Manquemapu, Purranque , Osorno , Región de Los Lagos, -40.8904 -73.84912, 2018-11-30, coll. J. Pérez-Schultheiss, under stones, in low herbaceous vegetation, JP-394. 1 male, 2 females (MNHNCL AMP-15989) : Manquemapu, Purranque, Osorno , Región de Los Lagos, - 40.8904 -73.84912, 2019-10-16, Coll. J. Pérez-Schultheiss, under stones, Lliuco river estuary, next to the bridge, JP-436. 1 male (MNHNCL AMP-15990) , 6 males, 3 females (MNHNCL AMP-15991) : Marismas Rio Quilo, Ancud, Chiloé , Región de Los Lagos, -41.87076 -73.98223, 2007-10-05, coll. J. Pérez-Schultheiss, U. Mosqueira & L. Muñoz, under wooden planks and stones, JP-8. 3 males, 9 females (MNHNCL AMP-15992) : Pucatrihue, San Juan de la Costa, Osorno , Región de Los Lagos, -40.53901 -73.71459, 2005-05-01, coll. J. Pérez-Schultheiss, under logs at the edge of the road, foot of the cliff, clear terrain. 31 males, 17 females (MNHNCL AMP-15993) : Humedal de Carampangue , Arauco, Región del Biobío, -37.2358 -73.3031, 2017-11-20, coll. Cristina Coccia, Trampas pitfall, associated to Spartina . 1 male A (MNHNCL AMP-15994), 1 male C (MNHNCL AMP-15995), 1 male D (MNHNCL AMP-15996), 1 female E (MNHNCL AMP-15997), 1 female F (MNHNCL AMP-15998), 1 male (MNHNCL AMP-15999), 3 males, 11 females (MNHNCL AMP-16000) : Manquemapu, Purranque, Osorno , Región de Los Lagos, -40.89034 -73.849217, 2018-11-02, coll. J. Pérez-Schultheiss, F. Urra & D. Cotoras.

Etymology: The specific epithet “oyarzuni ” is after Carlos Oyarzún Segovia, marine biologist from the Environmental Office and Purranque Natural History Museum of the Ilustre Municipalidad de Purranque (Los Lagos region, Chile), in recognition for his permanent effort to support the scientific research in the coastal area of the commune of Purranque. Thanks to Carlos every year from 2016 we were able to reach Manquemapu and doing sustained research for collect and studying the invertebrate biodiversity, obtaining the first specimens of the new species.

Diagnosis: As for the genus.

Description: Holotype male, 8.6 mm. Eye medium size, round, 1/5–1/3 head length. Antenna 1 (fig. 8A1) short, not reaching the midpoint of peduncle article 5 of antenna 2, flagellum with 5 articles. Antenna 2 (fig. 8A2) longer than head and first 3 pereonites, peduncular articles slightly inflated and with sparse, small robust setae (cf with fig. 8A2b); flagellum with 16 articles. Mandible left lacinia mobilis 4-dentate (cf. fig. 8MLa). Maxilliped (cf. fig. 8MXPa) palp, article 2 with distomedial lobe, article 4 distinct and small, button-shaped.

Gnathopod 1(fig. 9GN1) sexually dimorphic; subchelate; posterior margin of merus and carpus with lobe covered in palmate setae; propodus subrectangular, with posterodistal lobe well developed; palm short, transverse; dactylus as long as palm. Gnathopod 2 (fig. 9GN2) sexually dimorphic; subchelate; merus without medial lobe; carpus triangular, reduced, enclosed by merus and propodus; palm acute, convex, smooth, posterodistal corner defined by an abrupt slope, without a special robust seta; dactylus as long as palm, not attenuated distally. Coxae 2–4 as wide as deep (fig. 9GN2). Pereopods 3–7 cuspidactylate; dactylus without row or patch of dorsal short setae. Pereopod 4 (fig. 10P4) subequal or slightly shorter than pereopod 3. Pereopod 4 dactylus similar to pereopod 3 dactylus. Pereopod 5 (fig. 10P5) propodus distinctly longer than carpus. Pereopod 6 (fig. 11P6) not sexually dimorphic; shorter than pereopod 7; coxa posterior lobe anterodistal corner rounded, with marginal setae; carpus slender. Pereopod 7 (fig. 11P7) basis posterior margin subrectangular, dentate, with slightly produced posterodistal angle in an acute subtriangular lobe (cf. with 11B7b); merus posterodistal angle produced in an acute lobe, curved medially (cf fig. 11P7c); distal articles slender. Coxal gills on pereopods 2 and 6 larger than those on pereopods 3–5; coxal gill 2 bilobate and 3–6 unilobate, slightly folded.

Pleopods 1–3 well developed and biramous. Epimeron 2 subequal in length to epimeron 3. Epimeron 3 ventral margin smooth, without setae, posterior margin with small sparse setae, posteroventral corner with small subacute spine. Uropod 1 (fig. 10U1) peduncle with 4–6 robust setae per margin; distolateral robust seta absent; inner ramus subequal in length to outer ramus; inner ramus with 4 marginal robust setae in dorsomedial row and 3 in dorsolateral row; outer ramus with 3 robust setae. Uropod 2 (fig. 10U2) peduncle with 3–4 robust setae in two rows; inner ramus subequal in length to outer ramus; inner ramus with 2 marginal robust setae in dorsomedial and dorsolateral row; outer ramus with 2 marginal robust setae. Uropod 3 (fig. 10U3) peduncle with 2 robust setae; ramus subequal to peduncle, rod-like, parallel sided and slightly constricted to the apex, with 2–3 marginal seta, and 4 to 5 apical setae. Telson (fig. 10T) slightly longer than wide; apically incised; with 6–11 robust setae per lobe; dorsal midline not defined.

Female (sexually dimorphic characters), 11.1 mm (paratype E, 11.10 mm, MNHNCL AMP-15973). Antennae 1 with 5 articles. Gnathopod 1 simple (fig. 9GN1c); propodus subrectangular. Gnathopod 2 (fig. 9GN2c) mitten-shaped; basis narrow, 3.4× longer than wide; posterior margin of carpus and propodus with rugose lobe; dactylus shorter than palm. Oostegites (fig. 9GN2c) longer than wide; setae simple, without curl-tips. Oostegites 2–4 moderately setose, with 18, 12 and 12 setae respectively. Uropod 3 peduncle with 2 robust setae.

Distribution: The species has been observed in central-south Chile, from Carampangue (Biobío Region) to Putemún, Chiloé island (Los Lagos Region) ( Fig. 12C ), both in estuaries ( Fig. 13C ) and in rocky intertidal habitats ( Fig. 13D ).

Remarks: Lafkenorchestia oyarzuni sp. nov. is a small-sized species, which in its habitat could be confused with juvenile individuals of Transorchestia chiliensis or Orchestia sp. ; however, it is easily recognized from these species by the shape of uropod 3, which has a slenderer peduncle and a proportionally longer ramus; it also differs in the shape of the telson, which that is less abruptly narrowed and shows a different distribution of marginal setae.

No specimen of Carampangue shows well developed sexual dimorphism in pereopod 7; however, it is possible that all of them are immature with overestimated body size due to their bloating and extension by overhydration because the sampling method, in barber traps.

Figures

FIGURE 1. Habitus of new species of Talitridae. A: Atacamorchestia atacamensis sp. nov., male holotype (MNHNCL AMP- 15250). B: Lafkenorchestia oyarzuni sp. nov., male paratype I (MNHNCL AMP-15967).

FIGURE 8. Lafkenorchestia oyarzuni gen. et sp. nov., male holotype (MNHNCL AMP-15966), male paratype B (MNHNCL AMP-15975) (a), male paratype I (MNHNCL AMP-15967) (b) and female paratype E (MNHNCL AMP-15973) (c), cephalic appendages. Abbreviations: A1= antenna 1; A2= antenna 2; LL= lower lip; UL= upper lip; ML= left mandible; MD= right mandible; MX1= maxilla 1; MX2= maxilla 2; MXP= maxilliped.

FIGURE 9. Lafkenorchestia oyarzuni gen. et sp. nov., male holotype (MNHNCL AMP-15966), male A Carampangue (MNHNCL AMP-15997) (a), male B Carampangue (MNHNCL AMP-15981) (b) and female paratype E (MNHNCL AMP- 15973) (c), gnathopods. Abbreviations: GN1= gnathopod 1; GN2= gnathopod 2.

FIGURE 10. Lafkenorchestia oyarzuni gen. et sp. nov., male holotype (MNHNCL AMP-15966) and male A Carampangue (MNHNCL AMP-15997) (a), gnathopods. Abbreviations: P3-5= pereopods 3 to 5; U1-3= uropods 1 to 3; T= telson.

FIGURE 11. Lafkenorchestia oyarzuni gen. et sp. nov., male holotype (MNHNCL AMP-15966), male paratype B (MNHNCL AMP-15975) (a), male paratype C (MNHNCL AMP-15971) (b), male paratype I (MNHNCL AMP-15967) (c) and female paratype E (MNHNCL AMP-15973) (d), pereopods 6 and 7. Abbreviations: P6= pereopod 6; P7= pereopod 7; B7= basis of pereopod 7; M= dorsal view of male pereopod 7 merus and propodus, showing the posterodistal lobe curved medially.

FIGURE 12. Distribution of the studied taxa, with localities of collection for material examined. A, Platorchestia sp. B, Atacamorchestia atacamensis sp. nov. C, Lafkenorchestia oyarzuni sp. nov.

FIGURE 13. Habitat of the studied taxa, ordered from north to south in the Chilean coast.A, small coastal creek in Antofagasta (23.61336 -70.39204), habitat of Platorchestia sp. B, coastal area in Fray Jorge National Park (-30.6205 -71.7092), habitat of Atacamorchestia atacamensis sp. nov. C, Lliuco river estuary (-40.8904 -73.84912) and D, el Galpón beach (-40.8905 - 73.8485), typical habitats of Lafkenorchestia oyarzuni sp. nov.