Joculator problematicus Albano & Steger, 2021

Albano, Paolo G., Steger, Jan, Bakker, Piet A. J., Bogi, Cesare, Bosnjak, Marija, Guy-Haim, Tamar, Huseyinoglu, Mehmet Fatih, LaFollette, Patrick I., Lubinevsky, Hadas, Mulas, Martina, Stockinger, Martina, Azzarone, Michele & Sabelli, Bruno, 2021, Numerous new records of tropical non-indigenous species in the Eastern Mediterranean highlight the challenges of their recognition and identification, ZooKeys 1010, pp. 1-95 : 1

Joculator problematicus Albano & Steger sp. nov. Figure 11

Type material.

Holotype. Israel • spcm; Ashqelon; 31.6868°N, 34.5516°E; depth 11 m; 31 Oct. 2018; offshore rocky reef; suction sampler; HELM project (sample S58_3F); NHMW-MO-113580.

Paratypes. Israel • spcm; west of Rosh HaNikra Islands; 33.0704°N, 35.0926°E; depth 12 m; 1 May 2018; rocky substrate; suction sampler; HELM project (sample S14_2F); MNHN-IM-2012-25505 (paratype 1) • spcm; same collecting data as for paratype 1; HELM project (sample S14_4F); MZUB 60400 (paratype 2) • spcm; same collecting data as for paratype 1; 29 Oct. 2018; HELM project (sample S52_3F); SMF 360591 (paratype 3) • spcm; same collecting data as for paratype 1; HELM project (sample S14_2F); SMNH MO 99705 (paratype 4).

Additional material examined.

Israel • 5 spcms; Ashqelon; 31.6868°N, 34.5516°E; depth 12 m; 30 Apr. 2018; offshore rocky reef; suction sampler; HELM project (samples S12_1F, S12_2F, S12_3F) • 6 spcms; same collecting data as for preceding; depth 11 m; 31 Oct. 2018; HELM project (samples S58_1F, S58_2F, S58_3F) • 1 spcm; Ashqelon; 31.6891°N, 34.5257°E; depth 25 m; 2 May 2018; offshore rocky reef; suction sampler; HELM project (sample S16_2F) • 2 spcms; same collecting data as for preceding; depth 28 m; 31 Oct. 2018; HELM project (samples S59_3F, S59_3M) • 1 sh; Sdot Yam; 32.5299°N, 34.8599°E; depth 24 m; 3 May 2018; rocky substrate; suction sampler; HELM project (sample S17_1F) • 3 spcms; west of Rosh HaNikra Islands; 33.0704°N, 35.0926°E; depth 12 m; 1 May 2018; rocky substrate; suction sampler; HELM project (samples S14_2F, S14_4F) • 16 spcms; same collecting data as for preceding; 29 Oct. 2018; HELM project (samples S52_1F, S52_1M, S52_2F, S52_3F) • 2 spcms; west of Rosh HaNikra Islands; 33.0725°N, 35.0923°E; depth 20 m; 1 May 2018; rocky substrate; suction sampler; HELM project (sample S13_1F) • 9 spcms; same collecting data as for preceding; depth 19 m; 29 Oct. 2018; HELM project (samples S53_1F, S53_2F, S53_3F, S53_3M).

Diagnosis.

Very small bulbous brown shell, of ~ 1.5 mm in height and <1 mm in width, with a relatively short, almost smooth protoconch.

Description.

Color: Protoconch white, teleoconch brown with white outer lip margin.

Dimensions: H 1.6 mm, W 0.7 mm (holotype), H 1.4 mm, W 0.7 mm (paratype 1), H 1.5 mm, W 0.7 mm (paratype 2), H 1.5 mm, W 0.7 mm (paratype 3), H 1.6 mm, W 0.8 mm (paratype 4).

Protoconch: composed of 3.5 whorls with no clear demarcation between protoconchs I and II, height: ~ 300 µm, width ~ 200 µm (holotype), but accurate measurement hampered by the last protoconch whorl being covered by the first teleoconch whorl. It appears smooth except for growth lines and fine pustules covering the lower half of the first whorl and sparsely present apically and abapically on the following whorls (only visible with scanning electron microscopy at high magnification).

Teleoconch: 4 whorls (holotype), height: 1.4 mm (holotype). It bears three spiral cords of equal size, with tubercles at the intersection of orthocline axial ribs. The base is contracted and has two additional tuberculate spiral cords. Tubercles become oblong near the lip. Anterior siphonal canal short, reverted upwards, formed by a prong-like protrusion of the anterior outer lip (Figure 11A ); posterior siphonal canal notch-like.

Etymology.

The name Joculator problematicus refers to the difficult task of recognizing and identifying non-indigenous species belonging to groups whose taxonomy in the tropical seas is poorly known (see Discussion). The species epithet is an adjective in nominative singular masculine.

Remarks.

This species is characterized by its bulbous contour and constricted last whorl which justify its inclusion in the genus Joculator Hedley, 1909 ( Hedley 1909; Marshall 1978).

The Cerithiopsidae of the Indo-Pacific have been subject to numerous in-depth studies ( Cecalupo and Perugia 2011, 2013, 2014a, b, 2016, 2017a, b, 2018, 2019a, b, c). Still, this species does not fit any of the known species. Among the most similar species in terms of shell shape and ornamentation, Joculator itiensis Cecalupo & Perugia, 2014 has one teleoconch whorl more and a different color pattern characterized by light brown first whorl and base, J. olivoideus Cecalupo & Perugia, 2018 can be distinguished by its clearly prosocline axial ribs and greyish tubercles, and J. sekensis Cecalupo & Perugia, 2018 has only two spiral cords and blunter axial ribs on the first teleoconch whorl, in addition to a blunter siphonal canal.

There are several more species of small brown bulbous Joculator often distinguishable only by subtle character differences. Joculator priorai Cecalupo & Perugia, 2012 is corneous in color and has a pointed protoconch with one additional whorl; moreover, in our specimens the interspaces between the spiral cords are smaller. Joculator pupiformis Cecalupo & Perugia, 2012 has one protoconch and one teleoconch whorl more, the tubercles are oblong, and the base lacks a clearly visible fifth tuberculate spiral cord. Joculator fuscus Cecalupo & Perugia, 2012 has much broader interspaces between cords and a wide subquadrangular aperture which is, in contrast, quite small in our specimens. Joculator furvus Cecalupo & Perugia, 2012 has a neat abapical smooth cord on the protoconch, one teleoconch whorl less and a broader aperture. Joculator carpatinus Cecalupo & Perugia, 2012 has one protoconch whorl more, one teleoconch whorl less, a broader aperture and a fine abapical thread on the protoconch. Joculator caliginosus Cecalupo & Perugia, 2012 has one protoconch whorl more and one teleoconch whorl less, the basal fourth and fifth cords are only weakly tuberculate whereas they are neatly tuberculate in our specimens. Joculator coffeus and J. subglobosus , both Cecalupo & Perugia, 2013, have one clear abapical thread on the protoconch, one teleoconch whorl less, the shell has a more roundish shape and the lip does not reach anteriorly the siphonal canal, almost covering it, like in our specimens. The other representatives of Joculator include also other more elongated species that can be easily distinguished from our specimens.

This species is superficially similar to the native Mediterranean Cerithiopsis ladae Prkić & Buzzurro, 2007, which, however, can be distinguished at once for not having the last protoconch whorl partially covered by the first teleoconch whorl and lacking the prong-like process of the anterior outer lip. Additionally, tubercles in C. ladae on the last whorl are more elongated, subrectangular, and the shell profile is less bulbous. Cerithiopsis greppii Buzzurro and Cecalupo, 2005, described from Turkey, has a rather oval profile, but not as bulbous as in our species; additionally, it has a paucispiral protoconch. Cerithiopsis micalii (Cecalupo and Villari, 1997), which also has a somewhat oval shell profile, can be quickly distinguished by its protoconch whose last two whorls bear strong axial ribs.

Unfortunately, a revision of Red Sea Cerithiopsidae is lacking, but given that Joculator is a broadly distributed genus in the Indo-Pacific province, we consider J. problematicus another previously undescribed Indo-Pacific species recently introduced to the Mediterranean Sea.

Figures

Figure 11. Joculator problematicus Albano & Steger, sp. nov., holotype, NHMW-MO- 113580, Ashqelon, Israel, HELM project (sample S 58 _ 3 F): front (A, B), left side (C), right side (D, E) and back (F) views, protoconch (G, H), microsculpture (I) and base and siphonal canal (J). Scale bars: 0.5 mm (A-F); 0.2 mm (G, H); 0.3 mm (I); 0.4 mm (J).