Schizomavella cornuta ( Heller, 1867 )

Reverter-Gil, Oscar, Souto, Javier, Novosel, Maja & Tilbrook, Kevin J., 2015, Adriatic species of Schizomavella (Bryozoa: Cheilostomata), Journal of Natural History 50, pp. 281-321 : 283-288

Schizomavella cornuta ( Heller, 1867)

( Figures 2 , 3 ; Table 2 )

Lepralia cornuta Heller, 1867: 110 , pl. 6, fig. 6.

? Lepralia auriculata var. leontiniensis Waters, 1878: 8 , pl. 1, fig. 5.

Lepralia auriculata var. leontiniensis: Waters 1879: 32 , pl. 11, fig. 3.

Schizoporella auriculata var. cuspidata Hincks 1880: 261 , pl. 29, fig. 8.

Schizoporella auriculata var. spathulata Hincks 1886: 270 , pl. 10, fig. 8c.

Schizomavella auriculata var. ornata Canu and Bassler 1930: 35 , pl. 3, figs 11 – 14.

Schizomavella auriculata: Gautier 1962: 132 .

Schizomavella auriculata var. leontiniensis: Gautier 1962: 137 . Schizomavella cuspidata: Hayward and Thorpe 1995: 665 , pl. 2; Reverter-Gil and Fernandez-Pulpeiro 1996: 263, fig. 4A – C (only); Hayward and Ryland 1999: 286, fig. 131 A, C (not 131B, D).

Schizomavella cornuta: Hayward and McKinney 2002: 57 , fig. 26 A – C; Novosel 2007: 62 (in part), fig. 26 E.

Schizomavella gautieri: Novosel 2007: 64 .

Not Schizoporella auriculata var. asymetrica Calvet, 1927: 20 , fig. 2. [= Schizomavella asymetrica ( Calvet, 1927) , see Hayward and McKinney, 2002].

Not Schizomavella auriculata var. asymetrica: Gautier 1962: 134 . [= Schizomavella asymetrica ( Calvet, 1927) , see Hayward and McKinney, 2002].

Not Schizoporella auriculata var. hirsuta Calvet, 1927: 20 . [= Schizomavella hirsuta ( Calvet, 1927) , see below].

Not Schizomavella auriculata var. cuspidata: Gautier 1962: 135 .

Not Schizomavella cornuta: Novosel 2007: 62 (in part), fig. 26 F.

Material examined

CNHM Inv. br. 52: St. 5, Iž Island , 44°03.078 N, 15°11.186 E, 2005, 29 m.

CNHM Inv. br. 53: St. 8, Jabuka Shoal (PJ-2), 43°06.060 N, 15°26.210 E, 28 August 2001, 19 m.

CNHM Inv. br. 54: St. 16, Korčula Island (Lucnjak), 42°94.973 N, 17°16.026 E, 24 April 2004, 15 – 20 m.

CNHM Inv. br. 55: St. 18, Mljet, 42°75.640 N, 17°38.389 E, June 2000, 35 – 38 m.

MNCN 25.03 /3885: St. 1, Ždralova Bay , 44°53.059 N, 14°53.458 E, 07/05/2000, 35 – 40 m.

MNCN 25.03 /3886: St. 2, Ćutin Islet (Cres), 44°72.393 N, 14°49.374 E, 7 October 2001, 1 – 12 m.

MNCN 25.03 /3887: St. 4, Dugi otok, 44°10.225 N, 14°48.307 E, 12 July 2003, 30 – 40 m.

MNCN 25.03 /3888: St. 7, Kornati (Mana), 43°47.922 N, 15°16.452 E, 10 July 2003, 10 – 20 m ( Figure 2A, B, D ) .

MNCN 25.03 /3889: St. 8, Jabuka Shoal (PJ-1), 43°06.060 N, 15°26.210 E, 27 August 2001, 24 m.

MNCN 25.03 /3890: St. 8, Jabuka Shoal (PJ-2), 43°06.060 N, 15°26.210 E, 28 August 2001, 16 m.

MNCN 25.03 /3891: St. 9, Jabuka Islet (J4), 43°05.500 N, 15°27.600 E, 29 August 2001, 10 – 15 m.

MNCN 25.03 /3892: St. 10, Brusnik (BR-2), 43°00.260 N, 15°47.560 E, 30 August 2001, 10 – 20 m.

MNCN 25.03 /3893: St. 11, Biševo (BI-01), 42°57.312 N, 16°00.261 E, 25 September 1998, 40 m.

MNCN 25.03 /3894: St. 12, Vis (VS-02), 43°04.430 N, 16°07.213 E, 02 October 1998, 30 m.

MNCN 25.03 /3895: St. 13, Sušac, 42°46.007 N, 16°30.530 E, 15 February 2006, 10 – 20 m.

MNCN 25.03 /3896: St. 15, Lastovo Island (LA-3), 42°72.378 N, 16°88.429 E, 15 May 1998, 30 m.

MNCN 25.03 /3897: St. 15, Lastovo Island (Struga), 42°72.378 N, 16°88.429 E, 07 March 2002, 30 – 35 m.

MNCN 25.03 /3898: St. 16, Korčula Island (Lučnjak), 42°94.973 N, 17°16.026 E, 24 April 2004, 15 – 20 m ( Figure 2C ) .

MNCN 25.03 /3899: St. 18, Mljet, 42°75.640 N, 17°38.389 E, June 2000, 35 – 38 m.

Other material examined

MM 2857 , MM 3024 : Schizoporella auriculata var . leontiniensis, Taranto Bay , Italy, RNS Washington , 11 September 1893, Waters coll.

NHMUK 1899.5.1.894: Schizomavella cuspidata , lectotype, Guernsey, Hincks coll.

NHMUK 1897.5.1.723: Schizomavella cuspidata , Guernsey, Hincks coll.

NHMUK 1899.5.1.985: Schizomavella cuspidata var. spathulata , type, Adriatic , Hincks coll. MNHN-Paléontologie (no registration number): Schizomavella auriculata var. ornata , type, Djerba (Tunisie), Canu coll.

Remarks

The Adriatic material studied in the present work fully matches the redescription of Schizomavella cornuta by Hayward and McKinney (2002).

Schizomavella cuspidata ( Hincks 1880) was for a long time confused with S. auriculata , until the redescription of both species by Hayward and Thorpe (1995). Many varieties of S. cuspidata were described from the western Mediterranean (see e.g. Calvet 1927; Canu and Bassler 1930; Gautier 1962), which have been considered by Reverter-Gil and Fernández-Pulpeiro (1996) as belonging to morphotypes of this species without taxonomic relevance. Later, Hayward and McKinney (2002) revised samples from the Heller collection, and found that the material of Lepralia cornuta was identical to S. cuspidata s. l., and consequently they renamed it as Schizomavella cornuta ; S. cuspidata is a junior synonym. However, it is not definitively clear if S. auriculata var. cuspidata s. s. and L. cornuta are actually conspecific. We have examined samples labelled as S. cuspidata from both the Atlantic and Mediterranean, including the lectotype of S. cuspidata (see Figure 3 ). As stated by previous authors, the frequency of enlarged avicularia and the degree of development of the suboral umbo are rather variable in different colonies; the width of the sinus is also variable. Hincks (1880) characterised his var. cuspidata (from Guernsey, English Channel) as having a conspicuous spike-like process on the front of the ovicell, and a very prominent avicularium. The lectotype specimen has a wide sinus with small condyles; only a few avicularia are enlarged, most of the time they are small, steeply inclined or even perpendicular to the frontal plane ( Figure 3A, B ). Notwithstanding, in other Atlantic material (e.g. NHMUK 1897.5.1.723, from Guernsey, Figure 3C ) the condyles appear larger, the proximolateral corners of the orifice are more marked and the avicularia are more frequently enlarged; all of these characters seem to be more similar to the Mediterranean material of S. cuspidata .

On the other hand, Waters (1878) described Lepralia auriculata var. leontiniensis from the Pliocene of Bruccoli (Sicily) which Reverter-Gil and Fernández-Pulpeiro (1996) considered to be a senior synonym of S. cuspidata . However, the identity of Waters ’ variety is unclear. Original material could not be checked, while the original figure ( Waters 1878, fig. 5) seems to show a different-shaped orifice, and avicularia somewhat triangular in shape and frequently detached from the orifice, thus resembling Stephanotheca arrogata ( Waters, 1879) (see Reverter-Gil et al. 2012). However, the record of var. leontiniensis made by Waters (1879) from Taranto Bay, Naples, does seem to correspond to S. cornuta . Original material no longer exists in the Waters collection, but we have examined two specimens (MM 2857, MM 3024, Figure 3D ) that came from the same locality, first assigned to Schizoporella auriculata var. ornata but later changed to var. leontiniensis . Years later, Hincks (1886) defined Schizoporella auriculata var. spathulata from the Adriatic as having an enlarged suboral avicularium. Having re-examined the type material ( Figure 3E ), we believe that this variety is conspecific with S. cornuta .

The ‘ umbonate ’ form of S. cuspidata seems to be absent from the Mediterranean. Previous records of similar material from this area ( Gautier 1962, as S. auriculata var. cuspidata ; revised by Reverter-Gil and Fernández-Pulpeiro 1996), actually belong to a different species (see S. mystacea sp. nov. below). A thorough revision of material assigned to S. cuspidata , and related species from the Atlanto – Mediterranean region will be necessary to ascertain the conspecificity of S. auriculata var. cuspidata and L. cornuta , if at all, but this is outside the constraints of the present paper. Therefore, we provisionally accept the synonymy proposed by Hayward and McKinney (2002).

Hayward and McKinney (2002) stated that in S. cornuta , both small and enlarged avicularia show a distinct Y-shaped foramen, but this shape is actually also present in other species (see below Schizomavella mystacea sp. nov. and Schizomavella rosae sp. nov.). According to Hayward and Thorpe (1995) and Hayward and Ryland (1999) this distinct foramen shape is only present in enlarged avicularia.

On the other hand, Hayward and McKinney (2002) also stated that the specimen figured by Hayward and Ryland (1999, fig. 131D) is not S. cornuta , but rather S. asymetrica ( Calvet, 1927) . We have examined the figured sample (NHMUK 1911.10.1.1538, Norman coll., British), and consider it to be Schizomavella teresae Reverter-Gil and Fernández-Pulpeiro, 1996 , a species already reported from the British Isles. However, another figured specimen ( Hayward and Ryland, 1999, fig. 131B) does belong to S. asymetrica .

Schizomavella cornuta seems to be common on the northwest European coast. Its distribution in the Mediterranean, where it has been often reported as S. auriculata (see Reverter- Gil and Fernández-Pulpeiro 1996), is imprecisely known owing to the frequency of its confusion with other species. That being said, S. cornuta must be common in the western Mediterranean as it was the most common species among the Adriatic material studied here.

Figures

Figure 2. Schizomavella cornuta. (A, B) Autozooids with spatulate avicularia (MNCN 25.03/3888, St. 7, Kornati); (C) primary orifice with small suboral avicularium (MNCN 25.03/3898, St. 16, Korčula Island); (D) ovicellate zooid with spatulate avicularium (MNCN 25.03/3888, St. 7, Kornati).

Figure 3. Schizomavella cornuta. (A) Ovicellate and non-ovicellate zooids (lectotype of Schizomavella cuspidata, NHMUK 1899.5.1.894); (B) (same) primary orifice; (C) a colony of S. cuspidata with spatulate avicularia, from Guernsey (NHMUK 1897.5.1.723); (D) Schizoporella auriculata var. leontiniensis, Taranto Bay (MM 3024); (E) type of Schizomavella cuspidata var. spathulata, Adriatic (NHMUK 1899.5.1.985) (F) type of Schizomavella auriculata var. ornata, Djerba (Tunisie).

Tables

Table 2. Measurements (in mm) of Schizomavella cornuta (Kornati).

	Mean	SD	Minimum	Maximum	N
Autozooid length	0.653	0.2011	0.476	0.788	22
Autozooid width	0.332	0.0760	0.284	0.394	22
Orifice length	0.104	0.0222	0.092	0.114	22
Orifice width	0.121	0.0258	0.104	0.127	22
Ovicell length	0.225	0.0667	0.198	0.247	11
Ovicell width	0.266	0.0805	0.203	0.297	11
Avicularium length	0.223	0.0575	0.165	0.277	20
Avicularium width	0.078	0.0199	0.057	0.096	20

Note: SD, standard deviation; N, number of measurements.