Eluma cristata sp. nov.

Figs 2, 3, 4, 5, 6 K

Eluma tuberculata Reboleira et al., 2015: 49 (partim: specimens from MSS near Gruta de Alcobertas, Estremenho Karst Massif).

Type material.

Holotype. Portugal • ♂; Alcobertas; 39°25'46.5"N, 8°54'59.0"W; 21.VII.2022; leg. R. P. Eusébio; MSS pitfall trap; MNHNC: MB 11: 001198 . Paratypes: Portugal • 137 ♂♂, 138 ♀♀; same data as holotype; MNHNC: MB 11: 001186, 001189, 001195, 001198, 001200 • 115 ♂♂, 121 ♀♀; 20.IX.2022; same data as for preceding; MNHNC: MB 11: 001203, 001207, 001209, 001213, 001216 • 5 ♂♂, 10 ♀♀; same data as for preceding; MZUF 10038 • 280 ♂♂, 240 ♀♀; 20.XII.2022; same data as for preceding; MNHNC: MB 11: 001291, 001295, 001296, 001301, 001302 • 10 ♂♂, 10 ♀♀; same data as for preceding; MZUF 10039 • 68 ♂♂, 103 ♀♀; 1.IV.2023; same data as for preceding; MNHNC: MB 11: 001348, 001351, 001354, 001356 .

Description.

Maximum length: ♂ 7.5 mm; ♀ 9.5 mm. Body strongly convex, able to roll up into perfect ball, euspheric type. Colour light brown, as in E. matae and E. tuberculata . Dorsal surface with ornamentation consisting of protruding crests on posterior margins of cephalon, pereonites 1–7 tergites and median part of pleonites 1–5, each crest ending in lobes of irregular shape and number; telson with two small paramedian tubercles (Figs 2 A – E, 3 A, G, H, 6 K). Dorsum with scattered pointed scale-setae (Fig. 3 B) and one line of noduli laterales per side located near top of crests on pereonites 1–7 far from lateral margins (Fig. 3 G). Cephalon (Figs 2 A – D, 3 A, 6 K) with triangular scutellum distinctly separated from and not bent over vertex; distinct frontal line and no postscutellar line; oblique antennary lobes, quadrangular and directed frontwards. Eye consisting of single large ocellus as in Fig. 2 A, C. Pereonite 1 (Figs 2 A, C, 3 C, D, 6 K) with deep dorsal groove on lateral margin, schisma on posterior corners with rounded inner lobe distinctly shorter than outer lobe; posterior margin slightly concave at sides. Pereonites 2 and 3 (Fig. 3 E, F) epimera quadrangular with small and rounded lobe on ventral side. Pereonites 4–7 with quadrangular epimera and straight posterior margins. Pleonites 3–5 (Fig. 3 G) with rectangular epimera, slightly divergent. Telson (Fig. 3 G, H) triangular, wider than long, with slightly concave sides and rounded apex. Antennula (Fig. 3 I) of three articles, second article much shorter than first and third, third article with tuft of superimposed aesthetascs subapically. Antenna (Fig. 4 A) with flagellum slightly shorter than fifth article of peduncle, second flagellar article more than twice as long as first, bearing two aesthetascs on middle part. Mandibles (Fig. 4 B, C) with dichotomized molar penicil and three or four free penicils; right mandible with one penicil and left mandible with two penicils on hairy lobe. Maxillula (Fig. 4 D) outer lobe with 4 + 6 (5 cleft) teeth; inner lobe with two thick subapical penicils and small triangular distal point. Maxilla (Fig. 4 E) apically setose with outer lobe rounded, much wider than inner lobe. Maxilliped (Fig. 4 F) with quadrangular endite bearing two triangular spines on distal margin and large subapical seta; basal article of palp with two large setae. Uropod (Fig. 4 G) flattened; exopod about twice as wide as long with slightly concave distal margin; endopod slightly protruding backwards compared with exopod.

Male. Pereopod 1–3 (Fig. 5 A) with line of pointed setae on sternal margins of carpus and, to lesser extent, merus. Pereopod 7 (Fig. 5 B) ischium with sternal margin distinctly concave, distal margin with rounded lobe and four stout setae; merus with sternal margin slightly convex; merus and carpus with line of long setae on sternal margin. Genital papilla (Fig. 5 C) fusiform. Pleopod 1 (Fig. 5 C) exopod with large distal lobe bent outwards and apically rounded; endopod with distal part quadrangular and short apical lobe directed outwards. Pleopod 2 (Fig. 5 D) exopod triangular with a line of about five short setae on outer margin; endopod slightly longer than exopod. Pleopods 3–5 exopods as in Fig. 5 E – G.

Etymology.

From Latin cristatus = crested. The name refers to the high crests on the posterior margins of the body segments.

Remarks.

At present, the genus Eluma comprises only five species, i. e., the four species included here and E. praticola Taiti & Rossano, 2015 from northern Morocco (see Schmalfuss 2003; Taiti and Rossano 2015; Cifuentes and Da Silva 2023). Eluma cristata sp. nov. is readily distinct from all the other species by the protruding dorsal crests on the posterior margins of the cephalon, pereonites and, to a lesser extent, pleonites. Moreover, it differs from E. caelata in lacking the basal triangular lobe on the male pereopod 7 merus (see fig. 32 F, G in Taiti and Rossano 2015); from this species and E. praticola also in the male pleopod 1 endopod with thickset distal part, not bent outwards; from E. matae also in the much shorter dorsal scale-setae of different shape (see fig. 4 A – F in Cifuentes and Da Silva 2023).

Ecological notes.

This species was only found in this MSS habitat.

Seasonal patterns in Portuguese MSS habitats.

This species was only found in Alcobertas, during all seasons, and with a decrease in abundance from spring to summer, highest abundance during fall and a new decrease in winter (Fig. 7 K).