Longibirotula antiqua Manconi and Samant, 2023

Samant, Bandana, Pronzato, Roberto, Mohabey, Dhananjay Mahendrakumar, Cubeddu, Tiziana, Stocchino, Giacinta Angela, Jangale, Krutika, Thalal, Pranay, Dhobale, Anup & Manconi, Renata, 2023, The oldest birotule-bearing freshwater sponges from the Upper Cretaceous-lower Paleocene Deccan volcanic-associated sediments of India, Acta Palaeontologica Polonica 68 (1), pp. 167-174 : 170-171

Longibirotula antiqua Manconi and Samant sp. nov.

Figs. 1–5 .

Zoobank LSID: urn:lsid:zoobank.org:act:A55B4EB4-F32C-41D0-B20C-C1609F643060

Etymology: From Latin antiqua , old.

Type material: Holotype, rock sample PGDG / NSKQ/2019 , slides PGNU / NSKQ /SL-1–13, stubs PGNU / NSK /ST-1, 2.

Type locality: Naskal GSI Quarry , 17°14’21” N, 77°53’16” E, Ranga Reddy District, Telangana State, India .

Type horizon: White marl/carbonate layers of Naskal GSI Quarry , Naskal intertrappean beds (Upper Cretaceous–lower Paleocene) .

Diagnosis.— Longibirotula antiqua sp. nov. is characterized by slender gemmuloscleres birotules with long spiny shaft, straight to slightly curved, with large scattered spines variably dense and numerous. Rotules flat with indented margins. Skeletal megascleres of two types, slim oxeas microspiny to smooth and short, stout acanthoxeas.

Description. —Skeletal megascleres monaxial with two morphotypes. Slim, long, microspiny to smooth oxeas (142– 425 × 6–13 µm) rarely sinuous. Shorter, stouter acanthoxeas (71–104 × 6–9 µm) straight to slightly curve with dense, large spines. Microscleres absent. Entire gemmules are not found because organic matter associated with gemmular theca is not preserved. Fossil remains are only represented by siliceous spicules. Gemmuloscleres birotules with very long, straight to slightly curved, spiny shaft (47–76 µm in length, 3–6 µm in thickness), with spines large, numerous, variably dense, and rotules flat with indented margins (12–19 µm in diameter).

Remarks. —Spicule deposits suggest that the Naskal intertrappean palaeolake was inhabited by a population of sponges with resting stages at the time of deposition. In addition, centric diatoms ( Aulacoseira spp. ) and aquatic to semiaquatic flora were also part of the biotic community.

Stratigraphic and geographic range. — Type locality and horizon only.

Figures

Fig. 1. Map of India showing Deccan volcanic province (green area). A. Location of Naskal intertrappean, Naskal B (white star) and Naskal GSI Quarry sections (red star); map modified after Ahluwalia (1990) and Wilson Mantilla et al. (2022). B. Sponge spicule and diatom bearing horizon in Naskal GSI Quarry section. C. Palynomorph bearing Naskal B section (modified after Wilson Mantilla et al. 2022).

Fig.2. Megascleres of palaeospongillid sponge Longibirotula antiqua gen.et sp. nov.from Upper Cretaceous–lower Paleocene of Naskal GSI Quarry (India). A–I. Oxeas (slides PGNU/NSKQ/SL-1–13) slim to stoutwith variably pointed tips.Diagenetic processes affect all spicules to various degree.Scale bars 20 µm. { fig. will be greyscale in printed version}

Fig. 3. Megascleres of palaeospongillid sponge Longibirotula antiqua gen. et sp. nov. from Upper Cretaceous–lower of Paleocene of Naskal GSI Quarry India). A–H. Acanthoxeas (slides PGNU/NSKQ/SL-1–13) with large spines. Diagenetic processes affect all spicules to various degree. Scale bars 20 µm.

Fig. 4. Gemmuloscleres of palaeospongillid sponge Longibirotula antiqua gen. et sp. non. from Upper Cretaceous–lower Paleocene of Naskal GSI Quarry (India). A–O. Birotules (slides PGNU/NSKQ/SL-1–13) slender, spiny, with long shaft. Diagenetic processes affect all spicules to various degree. Scale bars 20 µm.

Fig. 5. Spicular complement of skeleton and gemmules of palaeospongillid sponge Longibirotula antiquagen.et sp. nov.from Upper Cretaceous–lower Paleocene of Naskal GSI Quarry (India) (slides PGNU/NSKQ/ST-1, 2). A, B. Acanthoxeas short with dense spines.C, D. Oxeas fusiform, long and with acute tips. E, F. Birotules with long shaft. Diagenetic processes affect all spicules to various degree. Scale bars 20 µm.