Pholas (Thovana) campechiensis Gmelin, 1791

Delfino, Marina & Signorelli, Javier H., 2021, Fig. 13 in Fig. 12. Majella pristis n in Periclimenaeus djiboutensis Bruce 1970, Zoological Studies 60 (28), pp. 1-20 : 8-10

Pholas (Thovana) campechiensis Gmelin, 1791

( Fig. 5 )

Pholas campechiensis – Gmelin, 1791: 3216; Hanley 1842 –1856: 6, pl. 9, fig. 44; Abbott 1954: 461; Díaz Merlano and Puyana Hegedus 1994: 101; Scarabino 2003: 242; Scarabino et al. 2006: 396, 2016: 7; Turgeon et al. 2009: 737; Dias Passos and Magalhães 2011: 148; Capelo et al. 2014: 34; Velásquez et al. 2017: 254; De Vasconcellos et al. 2018: 52.

Pholas oblongata – Say, 1822: 320; Hanley 1842 –1856: 5; De Kay 1843: 248; Dall 1898: 815.

Pholas candeana – d'Orbigy, 1847 in 1834–1847: 215, pl. 25, figs.

18–19; Dall 1898: 815.

Thovana oblongata – Gray 1847: 187.

Dactylina campechensis – Adams and Adams 1856 in 1853–1856: 326; Fischer 1858: 49; Carpenter 1864: 635.

Dactylina candeana – Chenu 1862 in 1859–1862: 4, fig. 12.

Dactylina (Gitocentrum) campechensis – Tryon 1862: 204.

Pragmopholas (Gitocentrum) campechiensis – Fischer 1887: 1133.

Pholas (Thovana) campechiensis – Dall 1898: 815; Lamy 1925: 31–32; Lange de Morretes 1949: 49; Gofferjé 1950: 279; Turner 1954: 48, pl. 24, figs. 1–4; Olazarri 1962: 51; Klappenbach 1967: 166; Huber 2010: 473.

Type locality: “Sinu Campechiensi”, Gulf of Campeche, Mexico.

Type material: Pholas campechiensis : not found, species based on the illustration of Lister (1685 −1695, pl. 432, fig. 275, invalid) ( Fig. 5H ); Pholas oblongata : not found; Pholas candeana : NHMUK 1854.10.4.493, syntypes ( Fig. 5A–G ).

Description: Shell: Large, ovate-cylindrical, length up to 110 mm, sub-elliptical, very elongate, fragile, moderately gaped at both ends; anterior and posterior ends rounded ( Fig. 5A–F ); umbos well developed, sub central, placed on the anterior fourth of the valves; umbonal reflection double, the inferior one free at the anterior side of the umbos, the upper reflection septated ( Fig. 5A, C, E, G ), umbonal reflection usually eroded at the contact point with the complement valve ( Fig. 5B, D, F ); external surface with radial ribs almost covering the entire shell, only absent in the anterior part; concentric sculpture well defined, strong on the anterior slope, but weaker near the umbo; imbricated scales are observed where the radial ribs cross the concentric ridges ( Fig. 5A, C, E ); internally white; external sculpture usually visible from inside the shell; muscle scars and pallial line visible; pallial sinus broad and deep, about 60% of shell length; apophysis fragile, short but broad, posteriorly projected; three accessory plates observed; protoplax rectangular, longitudinally divided, posteriorly truncated; mesoplax transverse, trigonal, small, but broad; metaplax thin elongate, narrow.

Material examined: Brazil ─ Cananeia, Sao Paulo State ( MACN 11444); Uruguay ─ El Chuy, Rocha ( MACN 25711).

Distribution: From North Carolina to Texas, USA and throughout the Caribbean, in South America from Colombia, Venezuela, Suriname, Brazil and Uruguay ( Díaz Merlano and Puyana Hegedus 1994; Rios 1994 2009), eastern Atlantic from Senegal to Angola ( Díaz Merlano and Puyana Hegedus 1994; Cosel and Gofas 2019).

Remarks: Only two lots of Pholas (Thovana) campechiensis have been found deposited in the Argentine national collections ( MACN 11444, Cananeia, Brazil; MACN 25711, Chuy, Uruguay). Pholas (Thovana) campechiensis has been sampled deeply burrowed into compacted clay, wood, or soft rocks ( Díaz Merlano and Puyana Hegedus 1994; Rios 2009). Gmelin (1791) based the description of Pholas (T.) campechiensis on the illustration of Lister (1685 – 1695, pl. 432, fig. 275). Although no type material was found, this illustration confirms its generic position. The type material of Pholas oblongata could not be located into the cabinets of the Philadelphia Academy of Natural Sciences. According to Turner (1954), it is probably lost. However, this species was cited by several authors as junior synonym of P. (T.) campechiensis ( Turner 1954, Díaz Merlano and Puyana Hegedus 1994, Huber 2010, Velásquez et al. 2017) and even Say (1822) mentioned the morphological similarities with the Gmelin’s species. The analysis of type material of Pholas candeana ( NHMUK 1854.10.4.493, syntypes) confirmed its status as a junior synonym of P. (T.) campechiensis . Pholas (T.) campechiensis differs from the West African species P. (T.) bissauensis in its larger size and elongated and less compact shell, in the outer radial sculpture with widely spaced corrugations and in the less prominent umbonal reflection. The eastern Pacific species P. (T.) chiloensis has a larger and heavier shell, a higher umbonal reflection and a less sculpted posterior end than the observed in P. (T.) campechiensis .

Figures

Fig. 5. Pholas campechiensis. A−G, Pholas candeana d'Orbigny 1853 (in 1841, 1842, 1846, 1853), NHMUK 1854.10.4.493, syntypes. H, original description of Pholas campechiensis from Lister, 1685−1695. I−K, examined material, MACN 11444. Scale bars: A−F, H, I−J = 1 cm; G = 5 mm.