Buchnerillo atlanticus, Garcia & Robla, 2022

Garcia, Lluc & Robla, Jairo, 2022, Buchnerillo atlanticus sp. nov., a new halophilic woodlouse (Isopoda: Oniscidea: incertae sedis) from the Atlantic coast of the Iberian Peninsula, with ecological remarks, European Journal of Taxonomy 821, pp. 1-15 : 4-9

publication ID	https://doi.org/ 10.5852/ejt.2022.821.1793
publication LSID	lsid:zoobank.org:pub:2D78A872-DD3B-4D15-81CA-50BEA8E57821
DOI	https://doi.org/10.5281/zenodo.6581171
persistent identifier	https://treatment.plazi.org/id/39D99F57-E621-4F96-99EC-95AE7F48D45C
taxon LSID	lsid:zoobank.org:act:39D99F57-E621-4F96-99EC-95AE7F48D45C
treatment provided by	Felipe
scientific name	Buchnerillo atlanticus
status	sp. nov.

Treatment

Buchnerillo atlanticus View in CoL sp. nov.

urn:lsid:zoobank.org:act:39D99F57-E621-4F96-99EC-95AE7F48D45C

Figs 2–7 View Fig View Fig View Fig View Fig View Fig View Fig

Diagnosis

Species of Buchnerillo characterized by ovoid and endoantennal conglobation type. Cephalon, pereontergites and pleon-tergites smooth and covered with long setae regularly arranged. Frontal area striated, not grooved. Mandibles with dichotomized molar penicil. First pereon-tergite posterolateral corner without schisma. Endopod of male pleopod 1 with straight distal part.

Etymology

The name of the species comes from the Atlantic Ocean (concretely the Cantabrian Sea) which is the area where the specimens were collected.

Material examined

Holotype SPAIN • ♂; Principality of Asturias, Villaviciosa, Selorio (Conejera beach); 43º31′56.1″ N, 5º21′48.3″ W; 3 m a.s.l.; 3 Sep. 2021; J. Robla leg.; hand collected from the lower face of embedded stones; MNCN 20.04/14403 . GoogleMaps

Paratypes SPAIN • 3 ♀♀; same collection data as for holotype; MNCN 20.04/14404 to 20.04/14406 GoogleMaps • 1 ♀; same collection data as for holotype; 9 Jul. 2021; MNCN 20.04/14407 GoogleMaps • 10 specs; same collection data as for holotype; 13 Jul. 2021; MNCN 20.04/14408 to 20.04/14417 (both included) GoogleMaps • 1 ♂ (specimen mounted in 3 microscope slides); same collection data as for holotype; 1 Jul. 2021; MBCN 24683-1 to 24683-3 GoogleMaps • 1 ♀; same collection data as for holotype; 9 Jul. 2021; MBCN 23149 GoogleMaps .

Additional material

SPAIN • 1 ♀ (specimen used for SEM); same collection data as for holotype; 1 Jul. 2021; CLLG GoogleMaps .

Description

MEASUREMENTS. Maximum length observed: male 1.7 mm, female 3.2 mm.

COLOUR. Cephalon and epimera pale. Rest of body reddish or yellow-orange with darker irregular reticulated spots, with slight variability ( Figs 2A–B View Fig , 3D View Fig ).

BODY. Conglobation ovoid, endoantennal ( Figs 2C View Fig , 3A View Fig ). Surface of body without prominent tubercles; cephalon and tergites regularly covered with erected and long setae ( Figs 2A–B View Fig , 3A–B View Fig ) as follows: five rows of setae on cephalon and pereon-tergite 1; two rows on posterior half of pereon-tergites 2–7 and pleon; one row on pleotelson; setae emerge from cuticular pits ( Fig. 3C View Fig ).

CEPHALON. With frontal and suprantennal ridges, delimiting frontal shield; upper margin regularly curved; lower margins concave, delimiting on each side hollows in which antennae are housed during conglobation ( Fig. 3A View Fig ). Frontal shield surface covered with fine transverse striae ( Fig. 3A View Fig ). Eyes formed by one ocular spot, not well-defined as ommatidium.

PEREON. Pereon-tergite 1 with anterolateral margin rounded and protruded; posterolateral margin without schisma; with short ventral lobe ( Fig. 4A View Fig ); hind margin straight. Pereon-tergites 2–4 with slightly sinuous hind margin; epimera subtriangular, with rounded lateral margins. Pereon-tergites 3–7 with quadrangular epimera.

PLEON. Pleon-tergites 1–2 not visible. Epimera of pleon-tergite 3 not visible. Pleon-tergites 4–5 with straight lateral margin ( Fig. 3B View Fig ).

PLEOTELSON. Twice wider than long, with curved anterior edge, converging sides, and straight hind margin ( Fig. 3A View Fig ).

FIRST ANTENNA. Two articles; first article slightly longer than second; second article with two long apical aesthetascs ( Fig. 4B View Fig ).

SECOND ANTENNA. Thick and short, with long setae on peduncular articles; flagellum with three articles; two aesthetascs on second flagellar article ( Fig. 4C View Fig ).

MOUTHPARTS. Maxilliped: endite narrow, as long as 3/4 of palp length, with one thin apical penicillium; palp with two strong setae on basal article and one on distal article ( Fig. 5A View Fig ). Maxilla distally rounded, bearing about 10 tubular setae ( Fig. 5B View Fig ). Maxillula: inner branch distally pointed, without penicils ( Fig. 5D View Fig ); outer branch with 5+ 4 apically entire teeth and one supplementary seta among outer group ( Fig. 5C View Fig ). Left mandible with dichotomized molar penicil, with 2+1 free penicils ( Fig. 5E View Fig ); right mandible with dichotomized molar penicil, with 1 +1 free penicils and toothed lacinia mobilis ( Fig. 5F View Fig ).

PEREOPODS. Short, with one long divided seta on carpus. Dactylus with long and plumose dactylar seta.

PLEOPODS. All exopodites without pleopodal lungs.

UROPODS. Endopod twice as long as exopod, both with long apical setae ( Fig. 6A View Fig ).

Male

Pereopods 1 and 7 without distinct modifications ( Fig. 6B–C View Fig ). First pleopod with exopod small, reniform, without setae; endopod with very wide basal part and narrow, almost straight, distal third ( Fig. 6D View Fig ). Second pleopod: exopod elongated-ovoid, with marginal hairs and two subdistal setae; endopod with long and thin distal half ( Fig. 6E View Fig ). Genital papilla as in Figure 6F View Fig .

Remarks

Buchnerillo atlanticus sp. nov. is distinguished from the other three known species of the genus, in addition to other morphological characteristics, by the lack of dorsal tubercles and by having long sensory setae. According to the respective original descriptions, it also differs from the other species by having the mandibles with dichotomized molar penicil, instead of semi-dichotomized. In addition to these morphological features, it is distinguished from B. litoralis by its ovoid rather than spherical conglobation ( Vandel 1960a), by the shape of the endopod of the first male pleopod, which in B. atlanticus is almost straight with a very wide basal part and in B. litoralis has a curved distal part, apically dilated ( Vandel 1960a). Both species have the frontal area of the cephalon not excavated, but covered with fine transverse striae. In addition to the characteristics already mentioned, B. atlanticus is distinguished from B. oceanicus by the cephalic structure, with striated instead of grooved frontal area ( Ferrara 1974). Buchnerillo atlanticus , B. litoralis and B. oceanicus share the lack of schisma in the first pereontergite and presence of a short lobe in its ventral part. Finally, B. atlanticus is also distinguished from B. neotropicalis by the absence of schisma in the first pereon-tergite and by the shape of the male first pleopods, among other characteristics ( Taiti et al. 2018). The most distinctive morphological features of the four known species of Buchnerillo are presented in Table 1 View Table 1 .

Distribution

Buchnerillo atlanticus sp. nov. is only known from its type locality of Conejera beach in Villaviciosa (Asturias, Spain) ( Fig. 1A–B View Fig ).Although several localities with similar ecological conditions were visited, no specimens were found. Up to date, each species of Buchnerillo belong to different coastal areas of the world: Buchnerillo litoralis occurs on the Mediterranean shores, B. oceanicus on the coasts of the Indian Ocean, B. neotropicalis on the coasts of the Pacific Ocean and B. atlanticus on the Cantabric coast of the Atlantic Ocean ( Fig. 7 View Fig ).

Ecology

Buchnerillo atlanticus sp. nov. was always found in Conejera beach areas with fine-grained sand. All the specimens were adherent to the lower face of large highly humid stones embedded in the substrate. Contrary to the habitat of other species of Buchnerillo , in the study area no logs or plants remains are present ( Fig. 1B View Fig ). Several specimens seemed to be seen feeding on small patches of algae and other organic material adhered to the rocks. Apparently, the presence of B. atlanticus was not altered by frequent survey and handling of the same stones in the short sampling period. Buchnerillo shared habitat with three other halophilic woodlice: Armadilloniscus candidus Budde-Lund, 1885 , Halophiloscia couchii (Kinahan, 1859) and Ligia oceanica (Linnaeus, 1767) . Buchnerillo atlanticus did not present particular conspecific aggregations. Other arthropods present in the area were the pseudoscorpion Neobisium maritimum Leach, 1817 and the chilopod Geophilus easoni Arthur et al., 2001 both potential predators of B. atlanticus . Several species of halophilic Collembola, staphylinid Coleoptera and tiny mites were also present in the study area, in addition to some other accidental arthropod taxa from the cliff. Regarding its behaviour, it was always seen moving slowly among the organic material and small grains of sand stuck to the lower face of the stone ( Fig. 2A–B View Fig ). In case of disturbance the individuals rolled into an ovoid ball that remained adhered to the surface due to the humidity ( Fig.2C View Fig ). The shape and colour of Buchnerillo provides this woodlouse with an almost perfect camouflage, looking like one more sand grain in the microhabitat under the stone ( Fig. 2A View Fig ). In case of a major or continuous disturbance it ended up opening slightly and releasing itself from the stone, falling to the substrate where they turn complete untraceable. The specimens showed some photophobic behaviour (Supplemental material). When the stones were lifted, B. atlanticus moved into the shade. This species is thought to be very sensible to dehydration. When specimens were removed from their habitat it only took a few minutes to die. Buchnerillo atlanticus needs constant humidity, present in its habitat under stones embedded in humid substrate. Its habitat is subject to tidal influence with occasional submersion. Specimens of B. atlanticus were seen between July and September, with a slightly variation in population abundance among consecutive days.