Sisonia frijellanae, Kiel & Fernando & Magtoto & Kase, 2022

Kiel, Steffen, Fernando, Allan Gil S., Magtoto, Clarence Y. & Kase, Tomoki, 2022, Mollusks from Miocene hydrocarbon-seep deposits in the Ilocos-Central Luzon Basin, Luzon Island, Philippines, Acta Palaeontologica Polonica 67 (4), pp. 917-947 : 934

publication ID

https://doi.org/ 10.4202/app.00977.2022

persistent identifier

https://treatment.plazi.org/id/0470A855-EA69-FF88-FF93-FF7288F3FC5A

treatment provided by

Felipe

scientific name

Sisonia frijellanae
status

sp. nov.

Sisonia frijellanae View in CoL sp. nov.

Fig. 17 View Fig .

Zoobank LCID: urn:lsid:zoobank.org:act:08086988-4440-4724-B293-0C12A48F2B82

Etymology: For Myra Vanessa A. Frijellana, Environmental Health and Safety Staff of the Northern Cement Corporation, who aided collecting at the quarry.

Type material: Holotype NIGSPAL-030, articulated specimen with exposed RV hinge . Paratypes: NRM Mo 192594–192596, 192598 (block B) , NRM Mo 192707 (block G), NRM Mo 192673, 192674 (block), articulated specimen with partially preserved shell, from the type locality and horizon.

Type locality: The “shale quarry” within the Northern Cement Corporation quarry in Pangasinan province, Luzon, Philippines .

Type horizon: Seep carbonate blocks enclosed in the Amlang Formation (Upper Miocene) .

Material.— 25 specimens from block B (NIGSPAL-031 [for a lot of 8 specimens]; NRM Mo 192594–192599, 192601– 192611) , 14 specimens from block G ( NRM Mo 192703– 192714) , 3 specimens from block I ( NRM Mo 192673– 192675) , one specimen from block J ( NRM Mo 192536). Upper Miocene of the “shale quarry” within the Northern Cement Corporation quarry in Pangasinan province, Luzon, Philippines .

Dimensions (in mm).—NIGSPAL-030: L = 39.6, H = 25.6, W = 20.7; NRM Mo 192595: L = 37.4, H = 24.7, W = 19.0; NRM Mo 192707: L = 32.4, H = 22.4, W = 13.5; NRM Mo 192674: L = 68.7, H = 40.0, W = 31.8; NRM Mo 192673: L = 48.5, H = 31.3, W (single) = 10.5.

Diagnosis.—Shell trapezoid to short modioliform in outline, strongly inflated, umbones in anterior third of shell, slightly elevated above hinge line, nearly orthogyrate; blunt ridges running from umbo to antero- and posterodorsal margins, area in between depressed; no lunule or escutcheon, ligament external; sculpture of fine growth increments only, internally with radiating striations; adductor muscle scars indistinct, pallial line entire, apparently no sinus; hinge with two strong, radiating cardinals in each valve.

Description.—Shell reaching 68.7 mm in length, strongly inflated, widest in posterior third of shell, outline short modioliform, dorsal and ventral margins subparallel, posterior margin truncate, anterior margin rounded to acutely rounded; ventral margin concave. Umbones broad, slightly elevated above hinge line, in anterior third of shell; ridge from umbo to posteroventral corner broad but distinct, ridge from umbo to anteroventral corner broad, indistinct; area between ridges deeply depressed, causing concavity of ventral margin; no sculpture except fine growth increments. Ligament short, resting on deeply incised nymphs; no lunule and escutcheon. Anterior adductor muscle scar indistinct, elongated pear-shaped, broadening ventrally, situated about midline of shell; pallial line starting just posterior of its ventral base; pallial line faintly impressed, moderately distant from shell margin, undulating, entire, apparently no sinus; anterior pedal retractor scar elongate, connected to adductor scar; posterior adductor muscle scar indistinct, shaped like an inverted comma, situated dorsally to groove running from umbo to posterior side of shell. Hinge plate narrow, subumbonal pit and two strong, short, radiating cardinals in each valve, RV with cardinal 1 and 3b, 3a apparently reduced, LV with cardinal 2a and 2b, cardinal 4 may be reduced.

Stratigraphic and geographic range. —Upper Miocene of Luzon, Philippines.

Class Gastropoda Cuvier, 1795 View in CoL

Unidentified limpet gastropod

Fig. 18A, B View Fig .

Material.— One poorly preserved specimen from block B ( NRM Mo 192585), 1 specimen from block F ( NRM Mo 192421), 1 specimen from block G ( NRM Mo 192715), 1 large specimen from block I ( NRM Mo 192656). Upper Miocene of the “shale quarry” within the Northern Cement Corporation quarry in Pangasinan province, Luzon, Philippines .

Dimensions (in mm).—NRM Mo 192421: L = 9.0, W = 7.5, H = 4.6; NRM Mo 192715: L = 6.2, W = 4.5, H = 2.5; NRM Mo 192656: L = 15.2, W = 11.8, H = 7.5.

Remarks.—Shape and the cancellate ornament of these specimens are very similar to species typically assigned to Bathyacmaea ( Okutani et al. 1992b; Jenkins et al. 2007a; Chen et al. 2019).

RV

Collection of Leptospira Strains

NRM

Swedish Museum of Natural History - Zoological Collections

Kingdom

Animalia

Phylum

Mollusca

Class

Bivalvia

Genus

Sisonia

Loc

Sisonia frijellanae

Kiel, Steffen, Fernando, Allan Gil S., Magtoto, Clarence Y. & Kase, Tomoki 2022
2022
Loc

Gastropoda

Cuvier 1795
1795
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