Zoosyst. Evol. 90 (2) 2014, 133–146 | DOI 10.3897/zse.90.8410 museum für naturkunde New genus and two new species of driftwood hoppers (Crustacea, Amphipoda, Talitridae) from northeast Atlantic and Mediterranean coastal regions David J. Wildish1,2 1 Fisheries & Oceans Canada, Biological Station, 531 Brandy Cove Road, St. Andrews, New Brunswick, E5B 2S9, Canada 2 Atlantic Reference Centre, Huntsman Marine Science Centre, 1 Lower Campus Road, St. Andrews, New Brunswick, E5B 2L7, Canada http://zoobank.org/D1D134DB-3E05-4434-9327-7BF90A912982 Corresponding author: David J. Wildish ([email protected]) Abstract Received 12 August 2014 A new specialist driftwood talitrid from the Swale, U.K., is figured and described as Ne- Accepted 21 September 2014 otenorchestia kenwildishi gen. n., sp. n. A further new driftwood talitrid, Macarorchestia Published 10 October 2014 pavesiae sp. n., is figured and described from coastal regions in the Adriatic Sea.Orches - tia microphtalma Amanieu & Salvat, 1963 from the Atlantic coast of France is re-des- Academic editor: ignated as Macarorchestia microphtalma (Amanieu & Salvat, 1963). A key is provided Matthias Glaubrecht for the known species of driftwood talitrids in northeastern Atlantic and Mediterranean coastal regions. Key Words Neotenorchestia kenwildishi gen. n., sp. n. Macarorchestia pavesiae sp. n. Macarorchestia microphtalma (Amanieu & Salvat, 1963) comb. n. Introduction supporting the lineal “island” theory was presented in Wildish (2012), showing that driftwood talitrids reached Driftwood specialist hoppers are a rare, difficult to find, the northeast Atlantic islands on driftwood transports. ecological group of Talitridae which are virtually con- After reaching the remote, recently-formed, volcanic fined to rotting driftwood where they live in galleries, islands they evolved further there into terrestrial or cav- consuming rotting driftwood and reproducing with rela- ernicolous forms if sub-tropical rain forest or seashore tively small broods (1 to 19 ova per brood in the Maca- caves were contiguous habitats with the supralittoral and rorchestia so far described). The ova are incubated in the also lacked a talitrid fauna. Alternatively driftwood spe- brood pouch formed by the oostegites on peraeon seg- cialists remained in place in their primary ecotope as su- ments 2 through 5 and hatch as juvenile forms. Because pralittoral, driftwood hoppers if the supply of driftwood talitrids have no larval stage their dispersal, particular- habitat was plentifully available. ly to distant oceanic islands, was seen as problematic. Currently known driftwood taxa (Wildish et al. 2012) The general view was that some form of passive rafting comprise 5 species presently grouped in 2 genera from dispersal was involved (Wildish 1988). In the lineal “is- the Mediterranean and northeast Atlantic (Macarorches- land” theory (Wildish 2012) this view was focussed and tia and Orchestia), with another genus (Platorchestia) the hypothesis proposed that driftwood hoppers, with reported from the west coast of North America by Bous- near-permanent residence in driftwood, were important field (1982). The preponderance of driftwood hoppers in agents of long distance dispersal for talitrids, particular- the northeast Atlantic/Mediterranean coastal areas is sug- ly to distant oceanic islands. Circumstantial evidence gested to be the result of more intensive sampling there. Copyright David J. Wildish. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 134 Wildish, D.J. : New species of driftwood talitrid hoppers Other geographic areas and particularly the southern Component species. Currently includes five species: M. hemisphere, where no driftwood hoppers have yet been martini, M. roffensis, M. remyi, M. pavesiae sp. n., M. found, have not been sampled intensively enough to con- microphtalma (Amanieu & Salvat, 1963) new comb. clude that they are without driftwood talitrid specialists. As a result of molecular studies of Macarorchestia Diagnosis. As in Stock (1989) except that the lacinia remyi it was suggested that two genetically distinguish- mobilis of the left mandible is 4 - 5 -dentate. The propo- able forms: one centred in the Tyrrhenian and the other dus of the seventh peraeopod carries distinctive tufts of in the Adriatic Sea were present (Pavesi et al. 2011). This long, slender setae, which are sexually dimorphic. The result was confirmed with further relative growth stud- first antenna with up to 5 articles (versus 3 in Stock). ies (Wildish et al. 2012) and a new species referable to The pleopods are biramous with a basis which is not Macarorchestia is described herein. Molecular and rel- reduced, but both rami are variously reduced dependant ative growth studies (Wildish et al. 2012; Pavesi et al. on the total body length of the largest adults of the spe- 2014) determined the taxonomic identity of an unknown cies. Thus in the smallest species, martini, there is no talitrid taxon found in a driftwood log which stranded in segmentation in the rami and 1-3 plumose setae and in the Swale, U.K., and found morphological evidence sup- the largest, microphtalma, there up to 5 segments and porting a generic level change in nomenclature for Or- 11 plumose setae. The pleopod rami may be sexually chestia microphtalma Amanieu & Salvat, 1963. A formal dimorphic, as in male M. remyi, and the second antennal presentation of the taxonomic changes outlined above is flagellum articles are sexually dimorphic in female M. provided with a key for the currently known driftwood pavesiae sp. n. In addition all species are small, that is species from the Mediterranean and northeast Atlantic to say < 15 mm in total body length and lack epidermal coastal region. pigment patterns. Material and methods Macarorchestia martini Stock, 1989 Stock 1989: 1109. Slides were prepared as temporary mounts without stain- ing and after dissecting mouthparts and limbs. Some Material examined. Male holotype and 8 females (al- were prepared as permanent mounts by Sara LeCroy, af- lotype and paratypes) on loan from Zoological Museum ter staining with lignin pink and permanently mounted in of Amsterdam, Amsterdam, the Netherlands (AMPH. CMCP-10 (Master’s Company, Inc.). 108.57). Collected by J. Stock on 2 August, 1987 from Photographs of limb parts were made with a Carl Gruta das Agulhas in Porto Judeus on the island of Ter- Zeiss photomicroscope and digital Canon 990 camera. ceira, Azores archipelago. Adobe Photoshop (version 7.0), Illustrator (version 11.0) and a Wacom tablet were used to draw limb parts Distribution. Known only from the type locality on the and prepare plates, essentially as outlined in Coleman island of Terceira. (2003, 2006). Antenna, mouth and limb part abbrevi- ations used throughout are: A1 = first antenna, A2 = Epidermal pigment patterns. Not mentioned by Stock second antenna, LL = lower lip (labium), UL = upper (1989). lip (labrum), RMnd = right mandible, LMnd = left mandible, Mx1 = first maxilla, Mx2 = second max- Remarks. This is the type species and smallest Maca- illa, Mxpd = maxilliped, Gn1 = first gnathopod , Gn2 rorchestia. Stock (1989) was equivocal about whether = second gnathopod, P3 to P7 = peraeopods 3 through this was a recent troglobiont specialist or trogloxenous 7, Pl1 to Pl3 = pleopods 1 through 3, Up1 to Up3 = form. I concur with the latter view and believe that the uropods 1 through 3, and T = telson. Body length was adaptations (small body length, body length greater in the measured accurately from digital photographs of each female, small eyes, reduced pleopod rami and shortened individual pinned in a dissecting dish. The total body length of the first 5 peraeopods) indicate that M. martini length (TBL) was measured from the most anterior part is a driftwood specialist. of the cephalon to the telson tip, on digital photographs with the aid of Image Pro Plus software. Limb ratios were calculated as Pl3/TBL, in units of mm. Macarorchestia roffensis (Wildish, 1969) Wildish 1969: 288; Lincoln 1979: 212; Wildish 1987: 571, Systematics as Orchestia remyi roffensisor O. roffensis; Ruffo 1993: 739. Genus Macarorchestia Stock, 1989 Material examined. Male holotype (BMNH 1968:64), Stock 1989: 1109; Ruffo 1993: 738. one female allotype (BMNH 1968:65) and 416 paratypes of all life history stages (BMNH 1968:66). Collected by Type species. M. martini Stock, 1989 D.J.Wildish(DJW) in August 1968, 0.2 km upstream from zse.pensoft.net Zoosyst. Evol. 90 (3) 2014, 133–146 135 Chatham Ness in Limehouse Reach, Medway estuary, posited in the Natural History Museum, Verona and Muse- near Rochester, Kent, U.K. um at Rome University, Rome, Italy by L. Pavesi. Distribution. Besides the type locality one other locali- Type locality. Lesina, Adriatic Sea, Italy (41°54’11”N, ty in the Medway estuary was found in 1968 with a few 15°26’50”E). specimens in a driftwood log by DJW. The location was ~ 0.6 km upstream from the old Rochester Bridge in Tower Other material examined. 17 individuals collected by Reach on the eastern shore. A few specimens collected by L.Pavesi in April 2006 at Varano, Adriatic Sea, Italy DJW in 1999 from the Swale, in Ferry Reach ~ 0.5 Km (41°55’12”N, 15°47’29”E). northwest of Kingsferry Bridge on the mainland shore. Diagnosis. M. pavesiae sp. n. is distinguished from its Epidermal pigment patterns. Absent. close relative, M. remyi, by its smaller size, sexually di- morphic second antennal flagellum articles in adult fe- Remarks. This is the second smallest Macarorchestia. males and absence of sexual dimorphism in pleopod rami. The type locality was destroyed during reclamation of Frindsbury marsh as an industrial estate. Description. Based on male paratypes: total body lengths in the range of 8.0 to 6.7 mm. Figs 1 and 2. The male holotype has similar morphology to male paratypes dis- Macarorchestia remyi (Schellenberg, 1950) sected in preparing the figures.