Vosmaeropsis anomala, Lopes & Padua & Azevedo & Klautau, 2025

Vosmaeropsis anomala sp. nov.

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( Figs 16–18 View FIGURE 16 View FIGURE 17 View FIGURE 18 ; Table 11 View TABLE 11 )

Etymology: From the latin anomalus (= irregular), refers to the irregular growth form of the species body.

Material examined: Holotype — UFRJPOR 8835 , Floating Pier at the Vitória Yacht Club , 31.iii.2017, colls. R. Rocha & L.M. Vieira . Paratype — UFRJPOR 8839 , same data as the holotype . Additional material — UFRJPOR 8937 , UFRJPOR 8938 , UFRJPOR 8940 , UFRJPOR 8950 , same data as the holotype .

Diagnosis: Vosmaeropsis with leuconoid aquiferous system. Cortical skeleton composed of triactines and microdiactines forming a reticulation. Subcortical skeleton composed of pseudosagittal triactines. Choanosomal skeleton composed of three categories of triactines and one of tetractines. Subatrial skeleton composed of triactines and tetractines. Atrial skeleton composed of strongly sagittal triactines and tetractines.

Description: Sponge tubular, repent or erect, light gray to beige in ethanol ( Fig 16A View FIGURE 16 ). Consistency rigid and uncompressible. Surface with ridges and projections, but smooth. Osculum at the top of lateral projections or a single apical aperture, with a bright membrane. Atrium central and smooth, with conspicuous excurrent canals. Aquiferous system leuconoid. All specimens presented reproductive elements, mostly larvae.

Oscular membrane supported by T-shaped triactines and tetractines. Cortical skeleton composed of microdiactines tangentially disposed, forming a reticulation, and triactines of variable sizes ( Fig 16B View FIGURE 16 ). Subcortical skeleton composed of sparse pseudosagittal triactines ( Fig 16C View FIGURE 16 ). Choanosomal skeleton disorganised ( Fig 16D View FIGURE 16 ), composed of three size categories of triactines and one category of tetractines. Triactines III and the tetractines surround the canals ( Figs 16D, E View FIGURE 16 ). Subatrial skeleton composed of triactines and tetractines ( Figs 16F, G View FIGURE 16 ). Atrial skeleton composed of triactines and tetractines ( Fig 16H View FIGURE 16 ). Abnormal tetractines with two apical actines ( Fig 17A View FIGURE 17 ) or one actine growing on another were observed ( Fig 17B View FIGURE 17 ).

Spicules ( Fig 18 View FIGURE 18 ; Table 11 View TABLE 11 ).

Microdiactines: Fusiform, one tip rounded and the other sharp, with large spines covering the entire spicule ( Fig 18A View FIGURE 18 ). We found three of these spicules without spines. Size: 57.5 (± 10.4)/ 2.7 µm (N = 20).

Cortical triactines: Subregular to sagittal. Actines cylindrical, with sharp tips. One actine frequently undulated ( Fig 18B View FIGURE 18 ). Size: paired actine—173.6 (± 19.8)/ 9.7 (± 1.4) µm (N = 20); unpaired actine—126.9 (± 19.5)/ 10.3 (± 1.7) µm (N = 20).

Subcortical triactines: Pseudosagittal.Actines cylindrical, straight or undulated, with sharp tips ( Fig 18C View FIGURE 18 ). Size: paired 1 actine—216.1 (± 32.3)/ 12.8 (± 1.9) µm (N = 20); paired 2 actine—128.6 (± 23.9)/ 11.4 (± 2.3) µm (N = 20); unpaired actine—112.0 (± 22.1)/ 10.9 (± 1.8) µm (N = 20).

Choanosomal triactines I: Regular to subregular. Huge. Actines conical, stout, with sharp tips ( Fig 18D View FIGURE 18 ). Size: 411.5 (± 87.2)/ 31.9 (± 7.8) µm (N = 20).

Choanosomal triactines II: Regular to subregular. Large. Actines cylindrical, with sharp tips ( Fig 18E View FIGURE 18 ). Size: 279.0 (± 43.8)/ 15.5 (± 5.1) µm (N = 20).

Choanosomal triactines III and tetractines (canals): Sagittal. Actines conical, with sharp tips. Paired actines curved ( Figs 18F, G View FIGURE 18 ). Apical actine of tetractines short, conical, slightly curved, with sharp tips. Tetractines are more abundant than the choanosomal triactines III. Size (triactines): paired actine—220.0 (± 21.9)/ 10.7 (± 1.8) µm (N = 20); unpaired actine—276.0 (± 34.2)/ 15.0 (± 2.3) µm (N = 20). Size: (tetractines): paired actine—156.4 (± 32.5)/ 11.3 (± 3.2) µm (N = 20); unpaired actine—208.8 (± 23.0)/ 15.0 µm (N = 2); apical actine—50.0 (± 14.5)/ 9.3 (± 2.4) µm (N = 20).

Subatrial triactines and tetractines: Sagittal. Actines conical to slightly conical, straight, with sharp tips. Paired actines smaller than the unpaired actine ( Figs 18H, I View FIGURE 18 ). Apical actine of tetractines short, cylindrical, straight, with sharp tip. Size (triactines): paired actine—172.5 (± 20.0)/ 14.5 (± 1.4) µm (N = 20); unpaired actine—262.3 (± 29.0)/ 16.4 (± 1.7) µm (N = 2). Size (tetractines): paired actine—192.8 (± 25.2)/ 13.0 (± 1.8) µm (N = 20); unpaired actine—262.8 (± 46.4)/ 15.0 (± 2.2) µm (N = 20); apical actine—42.4 (± 11.4)/ 8.4 (± 1.5) µm (N = 20).

Atrial triactines and tetractines: Strongly sagittal. Actines cylindrical, with blunt tips. Paired actines much longer than the unpaired and form an angle of 180º ( Figs 18J, K View FIGURE 18 ). The apical actine of the tetractines is short, conical, slightly curved, with sharp tip. Size (triactines): paired actine—171.9 (± 22.5)/ 10.5 (± 1.0) µm (N = 20); unpaired actine—72.6 (± 15.9)/ 8.2 (± 0.6) µm (N = 20). Size (tetractines): paired actine—174.4 (± 29.2)/ 10.0 (± 0.9) µm (N = 20); unpaired actine—77.2 (± 18.4)/ 8.5 (± 0.9) µm (N = 20); apical actine—27.7 (± 10.6)/ 6.2 (± 1.1) µm (N = 20).

Ecology: Specimens collected only on artificial substrates.

Distribution: Eastern Brazil ecoregion—Vitória, Espírito Santo State (type locality; present study).

Taxonomic remarks: Vosmaeropsis anomala sp. nov. can be differentiated from all the other 23 accepted species of the genus mainly by the skeleton composition.

Five species of Vosmaeropsis have microdiactines in the cortical skeleton, namely: Vosmaeropsis gardineri Ferrer-Hernández, 1916 , Vosmaeropsis japonica Hôzawa, 1929 , Vosmaeropsis macera ( Carter, 1886) , Vosmaeropsis oruetai Ferrer-Hernández, 1918 and Vosmaeropsis ovata Tanita, 1942 .

Vosmaeropsis gardineri can be differentiated from the new species because it does not have a subatrial skeleton and has only tetractines in the atrium. Vosmaeropsis japonica has cortical diactines and only triactines in the subatrial skeleton, while V. anomala sp. nov. does not have diactines (only microdiactines) and has subatrial triactines and tetractines. Vosmaeropsis macera and V. oruetai have cortical diactines and do not have atrial tetractines, and V. oruetai has also microdiactines in addition to the triactines in the atrial skeleton. The new species has atrial triactines and tetractines and no microdiactines in the atrial skeleton. Finally, the subatrial skeleton of V. ovata has only triactines, while again the new species has subatrial triactines and tetractines.

With the new species, Vosmaeropsis now comprises 24 valid species. The current diagnosis of the genus implies that only triactines compose the subatrial skeleton; however, V. anomala sp. nov. and other two species ( V. hispanica , and V. spinosa ) have triactines and tetractines in their subatrial skeleton, and one has only tetractines ( Vosmaeropsis levis Hôzawa, 1940 ; see Cavalcanti et al. 2015). Therefore, we emend the current diagnosis to consider tetractines in the subatrial skeleton:

Heteropiidae with sylleibid or leuconoid organisation. The choanoskeleton is composed of proximal subatrial triactines and/or tetractines and an irregular layer of scattered triactines and tetractines (modified from Borojević et al. 2002).