Cryptorchestia ruffoi Latella & Vonk

Davolos, Domenico, Matthaeis, Elvira De, Latella, Leonardo & Vonk, Ronald, 2017, Cryptorchestiaruffoi sp. n. from the island of Rhodes (Greece), revealed by morphological and phylogenetic analysis (Crustacea, Amphipoda, Talitridae), ZooKeys 652, pp. 37-54 : 40-44

Cryptorchestia ruffoi Latella & Vonk sp. n. Figs 2, 3, 4, 5, 6, 7, 8, 9

Type locality.

Island of Rhodes, Greece. A spring on Monte Smith and in streams flowing out of the springs called Epta Pyges (Seven Springs), Municipality of Archangelos.

Etymology.

Species named after Sandro Ruffo (1915 - 2010), tutor to us all, who worked on Mediterranean talitrid amphipods from an early stage.

Type specimens. Holotype male (15.7 mm): Greece, Rhodes Island, Rhodes, Monte Smith, near a little spring, June 1928, (labelled: Rodi VI-928 Monte Smiti, vicino piccola sorgente) (MSNVRCr 589). Paratypes: 9 males, 25 females; Greece, Rhodes, Psintos, Epta Piges spring's stream, 36°15'10.9'N - 28°06'49.3'E, 7/8-VII-2010, A. & L. Latella, V. Lencioni leg.: 1 male (vial RMNH.CRUS.A.5070 + slides RMNH.CRUS.21512-21515), 1 female (slides RMNH.CRUS.21516-21518), 2 male, 5 female RMNH.CRUS.A.5071; 4 males, 17 females MSNVRCr 590-611)

Additional material examined.

Cryptorchestia garbinii Ruffo, Tarocco & Latella, 2014: Italy, Lombardy, Brescia province, Lake Garda, between Desenzano and Padenghe, 45°29' N– 10°30'E, V-1895, A. Garbini leg.; Venetia, Verona province, Lake Garda, Peschiera, 45°26'51" N– 10°41'39"E, 18-IV-2010 L. Latella, V. Lencioni leg.

Cryptorchestia cavimana (Heller, 1865): Cyprus, Troodos Mountains, Kaledonia falls, 1250 m a.s.l., 9-VI-2000 M. Tarocco leg.; Cyprus, Troodos Mountains, between Prodromos and Troditissa, 1300 m a.s.l., 10-VI-2000, M. Tarocco leg.

Diagnosis.

Gnathopd 2 propodus sinusoid palmar margin with its strongest incursion close to the anterior side. Maxilla 1 with vestigial palp present on the outer lobe. Pereopod 5 with four groups of setae on the posterior margin in females and five groups in the males. Antenna first flagellum segment sometimes fused with second, forming a longer unit.

Description.

Based on adult males with an average length of 12.20 mm (Table 2). Head. Eyes large, subcircular, black. Antenna 1 (Figs 2, 3A) short, 1.46 mm long in average, slightly longer than peduncle article 4 of antenna 2, peduncle segment 2 slightly shorter than segment 3, flagellum with four articles. Antenna 2 (Figs 2, 3B) long, little shorter than half of the body length, article 5 longer than article 4, flagellar articles with four tufts of setae of which two spring from a hollow in a series of three fine setules, flagellum relatively short with 16-19 articles. In some antennae the first flagellum segment is fused with the second and forms a longer unit. Labrum (Fig. 4B) and labium (Fig. 3D) with very fine setules on anterior margin. Mandible (Fig. 3E) left with 4-dentate lacinia mobilis. Maxilla 1 (Fig. 3F) with nine robust and crenelated setae on inner lobe of which the innermost has a fine comb. A very small vestigial palp is observed. Maxilla 2 (Fig. 3C) with numerous apical setae, a double row on the inner lobe and a long, finely pinnate seta on its inner margin. Maxilliped (Fig. 4A) basal lobe with three blunt teeth on anterior margin, axial margin lined with robust setae armed with setules; palp article 4 reduced to a knob placed between two rows of setae.

Coxae. Coxal plate 1 with numerous robust setae on distal margin. Coxal plates 2-4 wider than deep, plate 5 elongated, bilobate, plates 6 and 7 smaller.

Pereon. Gnathopod 1 male (Fig. 4C) sexually dimorphic, subchelate; basis with anterior margin lined with six regularly spaced setae, posterior margin with four groups of setae; merus with small partly transparent lobe on posterior margin; carpus with five long setae, rugose at the tips, and placed at the posterior margin; propodus with transverse palm, and with a transparent lobe covering almost the entire palmar margin, and seven short setae lining the palmar margin; dactylus short, slightly longer than anterolateral margin of the propodus. Gnathopod 2 (Fig. 5A), subchelate; propodus oviform, stout with a rounded protuberance near dactylus insertion, palmar margin with large sinus in the anterodistal part; dactylus somewhat longer than palm. Pereopods 3-4 (Figs 5B, C) similar; merus of pereopod 3 shorter than that of pereopod 4; dactylus in pereopod 4 with straight inner margin. Pereopod 5 (Fig. 5D) basis with posterodistal lobe not very wide; propodus with five groups of robust setae on anterior margin. Pereopods 3-7 cuspidactylate. Pereopod 6 (Fig. 6A) shorter than pereopod 7; basis elongate; propodus slightly longer than carpus, anterior margin with five groups of long robust setae. Pereopod 7 (Fig. 6B) basis wide with distinct, rounded posterodistal lobe; merus and carpus not enlarged; propodus longer than carpus.

Pleon. Epimeral plate 2 with a small posteroventral tooth and almost smooth posterior margin. Pleopods 1-3 (Fig. 6C) well-developed, biramous, peduncle longer than rami; rami with slender setae; inner ramus slightly shorter than outer. Uropod 1 (Fig. 7A) with five axial and two medial setae on peduncle, one robust distolateral seta present; outer ramus subequal in length to inner ramus, both with four marginal setae and three apical setae (of which two robust and one small). Uropod 2 (Fig. 7B) peduncle with one robust distolateral seta, inner ramus subequal in length to outer, both with four lateral setae but inner one with two more setae not standing in line. Outer ramus with one strong apical seta and one smaller one, inner ramus with four apical setae. Uropod 3 (Fig. 7C) peduncle with two robust distolateral setae, ramus with four apical setae. Telson (Fig. 7D) longer than broad, dorsal midline entirely cleft, eight marginal and distal robust setae per lobe.

Female. Based on adult females with an average length of 11,24 mm (Table 2). Antenna 1 short, 1.1 mm length in average, flagellum with four articles. Antenna 2 long, 4 mm in average, flagellum with 15-16 articles. Gnathopod 1 (Fig. 8A) subchelate; coxal plate lower margin with numerous irregularly placed prominent setae; basis with several short setae, a regular row of three short robust setae on the posterior margin, a less regular row of six setae on the anterior margin; merus with two longer robust setae in a marginal row of 6 smaller ones; carpus with one very robust and long seta between several smaller on lower margin; propodus with three robust setae on lower margin and three bush-like groups on the palmar margin; dactylus slightly longer than palm. Gnathopod 2 (Fig. 8B), coxa curved, lower margin lined with small short setae; basis with at least 13 short strong setae on anterior margin, and only one in the middle of the posterior margin; ischium without setae; merus with conspicuous bulbous lobe, flattened or incurved at the end, three setae between lobe and proximal margin, some setae present inside lobe; carpus with lobe covering the entire lower margin; propodus with long lobe extending past the palmar margin towards the apex, lobe flattened at fore end; dactylus quite small, shorter than palm. Oostegites longer than wide; setae with simple straight tips.

Remarks.

The specimens from Rhodes differ in three main characters in comparison to Cryptorchestia cavimana (Cyprus), Cryptorchestia kosswigi (Ruffo, 1949) (Turkish coast), and Cryptorchestia garbinii (Garda Lake), in that they have the sinusoid palmar margin form in the propodus of gnathopod 2 of the male with the strongest incursion closer to the anterior side (Fig. 9A, B, C). Cryptorchestia ruffoi sp. n. differs also from Cryptorchestia garbinii and Cryptorchestia cavimana in the morphology of pereopod 7 basis, merus and carpus (Fig. 9D, E, F). There is also a vestigial palp present on the outer lobe of maxilla 1. This reduced palp has been observed before in Cryptorchestia monticola (Madeira). Another regular difference is the presence of four groups of setae on the posterior margin of pereopod 5 in the female specimens and five groups in the males. Out of ten specimens there were three males with five groups and seven females with four groups. A variable difference, in males and females alike, is that in some antennae the first flagellum segment is fused with the second and then both form a longer unit.

Overall, the morphological differences are subtle and perhaps only have meaning in the combination with a unique genetic signature in its COI and H3 gene fragments.