Conus (Fenestraconus)  yaquensis (Gabb, 1873)

Conus (Fenestraconus)  yaquensis myakka (Petuch & Drolshagen, 2011)

 

 

E’ una conchiglia robusta, turbinata. Le spire sono basse con l’angolo arrotondato e la parte superiore canalicolata. La forma è convessa sotto la sutura ed affusolata nella parte anteriore. La colorazione è formata da un fondo scuro tassellato con regolarità macchie chiare disposte lungo linee spirali(2). Per forma e dimensioni, questa conchiglia è molto simile al Conus cedonulli (2), ma la colorazione è completamente differente.

 

Le specie correlate al Conus Spurius possiedono un lungo opercolo e, sui primi giri, presentano noduli molto poco sviluppati o completamente assenti. Il Conus yaquensis potrebbe essere correlato al Conus lindae (Petuch, 1987), specie basata su un esemplare rinvenuto sulla costa a Sud dell’isola Grand Bahama a 240 metri di profondità e presente anche a profondità maggiori. Il Conus lindae ha una spalla più spigolosa rispetto al Conus yaquensis, anche se gli esemplari di dimensioni maggiori del Conus lindae sono più arrotondati. Anche la colorazione del Conus yaquensis, caratterizzata da spirali di grandi macchie bianche oblunghe, assomiglia a quella presente nel Conus lindae (1).

 

 

Diagnosis.–Aperture slightly wider at base than near shoulder; sutural ramps sigmoidal inprofile and lacking spiral ornamentation; subsutural flexure diagonal; raised spiral threads at base of shell, sometimes extending to shoulder; last whorl with reticulate (net-like) color pattern that is frequently

visible in normal light (3).

 

Description.–Shell dextral, medium-sized. Last whorl conical to broadly and/or ventricosely conical; outline convex. Aperture slightly wider at base than near shoulder. Shoulder subangulate to rounded. Spire of low to moderate height; outline fl at to slightly concave. Teleoconch sutural ramps sigmoidal in profi le. Subsutural fl exure diagonal, approximately twice as deep as wide. Last whorl with adapically elevated spiral ribbons on anterior third, in some smaller individuals persisting almost to shoulder as faint spiral threads. Color pattern on last whorl reticulate, forming ca. 15-20 spiral rows of unpigmented, rectangular to oval-shaped regions (3).

 

Occurrence.–Type locality/stratigraphic horizon unknown (Gabb [1873] gave only “Santo Domingo”). In the southeastern U. S., Conus yaquensis is known from the Tamiami Formation (Pinecrest Beds) of Charlotte, Collier, Hendry, Manatee, and Sarasota counties, Florida. Kamp (1967: 52) also reported this species from the Gatun Formation of Panama and “unnamed beds near Cartegena, Columbia.” (3)

 

Remarks.–The distinctive reticulate (or, netted) color pattern of Conus yaquensis, which is almost always observable under natural light, readily distinguishes it from all other cooccurring fossil species. Because this Conus species is easy to identify and relatively common in deposits of the Pinecrest Beds (Tamiami Formation), it could serve as a good guide fossil for recognizing these strata in the field. Despite viewing more than 500 specimens of C. yaquensis, I did not observe any specimens bearing early postnuclear whorls (they were eroded away in all cases), preventing inspection of relevant characters (3).

 

The holotype of C. jonesorum Petuch, 1994 (UF 66430, Pl. 15, Figs 4-5), bears the characteristic netted coloration pattern of C. yaquensis and is consistent in all other aspects of shell form as well. Petuch (1994: 355), however, stated that “Conus jonesorum is most similar to the older, stratigraphically-lower C. cherokus” (here considered a junior synonym of C. spurius), but made no reference to C. yaquensis (3).

 

 

 

3D MODEL PRI 70658    PRI 70658

 

 

Late Pliocene

Tamiami Formation (Pinecrest Beds) (S. FL)

 

Late Pliocene Map

 

 

 

 

Specimen of Conus yaquensis 

figured by Pilsbry (1921, pl. 21, fig. 6)

49 mm in length

 

 

Fenestraconus yaquensis (5)

 

Fenestraconus yaquensis myakka (5)

 

Fenestraconus myakkensis is the late Pliocene descendant of the early Pliocene F. yaquensis from the Dominican Republic.

Fruitville Member of the Tamiami Formation.

 

 

 

 

Conus yaquensis (1)

 

1-2:             Lectotype Repubblica Dominicana

3:                Paratype Repubblica Dominicana

4-5:             Conus jonesorum Holotype

6-9:             esemplari vari di Conus yaquensis

10-12: immagini in negativo ripresse con luce ultravioletta

 

 

 

 

 

 

 

Conus yaquensis (Gabb 1873)

mm. 42,9 x 25,0

Pliocene – Tamiami Formation (Pinecrest Beds)

[AZFC N. 166-01]

Conus yaquensis

25,3 x 15,0 mm.

 (PLIOCENE – Tamiami Form., Pinecrest  Member, Smr Pit, Sarasota)

[AZFC N. 166-02]

Conus yaquensis myakka

(Petuch and Drolshagen 2011)

56,3 x 33,5 mm.

(Petuch and Drolshagen 2011)

(PLIOCENE – Tamiami Form., Fruitville Member)

[AZFC 166-03]

 

 

Conus yaquensis myakka

(Petuch and Drolshagen 2011)

56,3 x 33,5 mm.

(Petuch and Drolshagen 2011)

(Pliocene – Tamiami Form., Fruitville Member)

[AZFC 166-03]

Conus yaquensis (Gabb 1873)

mm. 42,9 x 25,0

Pliocene – Tamiami Formation (Pinecrest Beds)

[AZFC N. 166-01]

Conus yaquensis myakka

39,3 x 21,4 mm.

Pliocene – Tamiami Form.

Fruitville Member

[AZFC 166-04]

Conus yaquensis (Gabb 1873)

mm. 31,2

Pliocene – Tamiami Formation (Pinecrest Beds)

Conus yaquensis

25,3 x 15,0 mm.

 Pliocene – Tamiami Form.

 Pinecrest  Member, Smr Pit

Sarasota

[AZFC N. 166-02]

 

 

Bibliografia Consultata

 

·        (4) - Neogene Atlas of Ancient Life Southeastern United States

·        (5) - 2011. Edward J. Petuch & Mardie Drolshagen, Compendium of Florida Fossil Shells, Volume 1 (Middle Miocene to Late Pleistocene Marine Gastropods, families Strombidae, Cypraeidade,, Ovulidae, Eocypraeidae, Triviidae, Conidae and Conilithidae). MdM Publishing, Florida, U.S.A.