Synurella aliciae, Jażdżewski, Krzysztof, Grabowski, Michał & Kupryjanowicz, Janusz, 2014

Jażdżewski, Krzysztof, Grabowski, Michał & Kupryjanowicz, Janusz, 2014, Further records of Amphipoda from Baltic Eocene amber with first evidence of prae-copulatory behaviour in a fossil amphipod and remarks on the taxonomic position of Palaeogammarus Zaddach, 1864, Zootaxa 3765 (5), pp. 401-417 : 410-411

Synurella aliciae sp. nov.

Description. Head without visible rostrum, slightly longer than first pereon segment; shape of cephalic lobe difficult to define. No eyes visible. Antenna I long, nearly of the body length ( Fig. 10 a). Number of articles in A I main flagellum around 20 (tips of flagella broken), accessory flagellum not visible due to some dust particles covering this part of A I. Antenna II length reaches half of A I. Flagellum of A II with less than 10 articles. Margins of pereonites and abdominal segments well seen only in dorsal parts. Margins devoid of armature; only 1 short setule set on dorsal surface of third abdominal tergite near hind margin ( Fig. 11 b). Epimeral plates II and III, discernible only in specimen B, postero-ventrally acutely produced ( Fig. 11 b). Urosome definitely unsegmented. Gnathopods in specimen A poorly visible—only anterior dorsal side of comparatively large propoduses could be observed. In the specimen B, only palmar margin of propodus and dactylus of gnathopod (I or II) visible ( Fig. 12 a). Palmar margin delicately concave, armed with 2 rows of several short robust setae, whereas palmar antero-distal angle widely rounded and armed with 2 groups of rather long setae. Short palmar setae seem to be not bifid. Dactyl ventral margin set with 3 setae. Pereopods III and IV invisible (broken or hidden), pereopods V–VII of similar length, although P V seems to be a little shorter than the next appendages. Bases of these posterior pereopods of widely rounded oval shape; their hind margins delicately serrated ( Fig. 11 b). In specimen A serrations of P V basis are set with short setules, whereas in specimen B serration only visible on hind margins of P VI and P VII basal articles. Merus, carpus and propodus of P V–VII of similar length. Distal parts of these articles armed with 2–4 robust setae of length equal or shorter than article width ( Fig. 11 b). Single seta also on the anterior and/or posterior margins of these articles, more numerously on P V propodus in specimen A. The length of P V–VII dactyls equal to half of propodus length. Apical setae of propodus not longer than half of dactyl length. Peduncles of uropods I and II strong. Their margins set with row of robust setae ( Fig. 12 c). Uropod rami poorly discernible in details but it seems that they are similar in length or somewhat shorter than peduncles. Only the armature of inner margin of U II endopodite in specimen B is better visible. This article apically armed with 3 robust setae and 1 such seta on its lateral margin. Uropod III not visible (possibly broken off) in both specimens. Telson visible in both specimens and turned upwards along urosome ( Figs 11 b and 12c). In specimen A it was possible to observe ventral surface of telson ( Fig. 12 d) deeply concave to more than half of its length and the tips of each lobe armed with 4 robust setae.

Etymology. This species is named in honour of Dr. Alicja Konopacka (Department of Invertebrate Zoology & Hydrobiology, University of Lodz, Poland), colleague and good friend of the first two authors, in recognition of long-lasting friendship and her contribution to the studies of Amphipoda over the years.

Figures

FIGURE 11. Synurella aliciae sp. nov.: a) habitus of specimen A, b) posterior part of specimen B.

FIGURE 12. Synurella aliciae sp. nov., details of morphology: a) distal part of G I or G II in specimen B, b) coxal plates I – IV, P V and P VI in specimen A, c) side view of urosome with protopodites of U I and U II and telson in specimen A, d) telson of specimen A.