Hyachelia tortugae Barnard, 1967

Iwasa-Arai, Tammy, Andrade, Sónia C. S., Miguel, Camila, Siqueira, Silvana G. L., Werneck, Max Rondon, Leite, Fosca P. P., Moraes, Lara, Santos, Marcelo Renan D., Medeiros, Luciana S., Lopes, Uylia H. & Serejo, Cristiana, 2023, Tuerkayana latens Ng and Hsi-Te Shih 2023, n. sp., Zoological Studies 62 (54), pp. 1-12 : 6-7

Hyachelia tortugae Barnard, 1967 ( Figs. 1 and 3 )

Hyachelia tortugae Barnard, 1967: 120–125 , figs. 1–4; Aguirre et al. 1998: 93; Yabut et al. 2014: 5, figs. 1A, 3, 4, 5A; Robinson et al. 2016: 1235–1237; Valencia et al. 2018: 86–88, figs. 1, 2.

Material examined: 8 males, 5 females, 2 juveniles, Santa Cruz, Aracruz, Espírito Santo, Brazil (19°57'40.3"S, 40°07'57.5"W), ZUEC CRU 4386.

Distribution: Type locality: Porto Nuñez, Santa Cruz Island, Galapagos (~ 0°45'S, 90°20'W), on green turtle Chelonia mydas ( Barnard, 1967) . Palmyra Atoll National Wildlife Refuge (5°53'N, 162°5'W), on C. mydas ( Yabut et al. 2014) . Parque Nacional Marino Las Baulas, Guanacaste, Costa Rica (10°20'N, 85°51'W), on C. mydas (Robinson et al. 2017) . Gorgona Island, Colombia (2°58'00"N, 78°11'24"W), on C. mydas ( Valencia et al. 2018) . Atlantic Ocean: Santa Cruz, Aracruz, Espírito Santo, Brazil (10°17'59.0"S, 36°17'25.6"W), on C. mydas (present study).

Remarks: Hyachelia tortugae from the Brazilian green turtles displayed the overall morphology found in the original description provided by Barnard (1967) and remarks from Yabut et al. (2014). This species was observed only on green turtle hosts.

Phylogenetic analysis

Sequences of species found on the Brazilian southeastern coast ( H. macrodactyla , P. hawaiensis , P. littoralis and S. youngi ) as well as H. lowryi and H. tortugae are newly available. Due to the low sampling of Talitrida , which comprises more than 700 spp (Horton et al. 2023), we resume our discussion of the relationships among Hyachelia spp. Within the infraorder Talitrida , there are four families represented in the present analysis: Brevitalitridae (terrestrial), Hyalidae (marine, shallow infralittoral and commensal), Hyalellidae (freshwater) and Talitridae (terrestrial or marine supralittoral). Hyalidae includes two subfamilies: The possibly polyphyletic Hyalinae ( Fig. 4 ); and Hyachelinae. Hyachelinae, comprised by H. lowryi and H. tortugae , was recovered both in ML and BI trees ( Figs. 4 and S 1 ). The Hyachelia clade showed long branch attraction, suggesting phylogenetic uncertainty, especially for 18SrRNA ( Fig. S1 ), complicating attempts to map the evolution of the gene ( Lindgren and Daly 2007). Therefore, a more comprehensive view of the evolutionary history requires knowledge of other molecular markers and inclusion of more sibling taxa to help understand the relationships.

Divergence time estimates are in agreement with the ages of the infraorder Amphipoda inferred by CopilaŞ-Ciocianu et al. (2020). According to our analyses, the ancestor of the genus Hyachelia originated in the Cretaceous around 127.66 Mya [95% highest posterior density intervals ( HPD): 87.00–174.64] and possibly represents the very first split of the infraorder Talitrida ( Fig. 1 ). Within the genus, Hyachelia tortugae and H. lowryi split in the Miocene, around 26.16 Mya (95% HPD: 9.36–46.43 Mya, Fig. 4 ).

Figures

Fig. 1. a, Hawksbill turtle (Eretmochelys imbricata) stranded in Alagoas, northeast Brazil. b, Amphipods (Hyachelia lowryi) associated to E. imbricata, arrow indicates H. lowryi specimens. c, Hyachelia lowryi Serejo and Sittrop, 2009 (ZUEC CRU 4385). d, Hyachelia tortugae Barnard, 1967 (ZUEC CRU 4386).

Fig. 3. Hyachelia tortugae Barnard, 1967 (ZUEC CRU 4386). a, Maxilliped, scale bar: 0.1 mm. b, Gnathopod 2, scale bar: 1.0 mm. c, Uropod 3, scale bar: 0.1 mm. d, Gnathopod 1, scale bar: 0.5 mm. e, Uropod 1, scale bar: 0.5 mm. f, Pereopod 4, scale bar: 0.5 mm. g, Pereopod 7, scale bar: 0.5 mm. h, Uropod 2, scale bar: 1.0 mm.

Fig. 4. COI+18SrRNA tree of Talitrida based on available sequences. Node values correspond to the estimated divergence time of Hyachelia. Red bars show the 95% highest posterior density. Bootstraps and posterior probability values are represented above branches for the Talitrida, Hyachelia, H. lowryi and H. tortugae. Red horizontal bars correspond to the 95% highest posterior density intervals (HPD). The gray vertical bar corresponds to Chelonioidea radiation according to Kear and Lee (2006).