On the genus Racekiela in Mexico: molecular and morphological description of Racekiela cresciscrystae n. sp. Author Patricia Gómez Author José Luis Carballo Author Cruz-Barraza, José Antonio Author Camacho-Cancino, Mildred text Journal of Natural History 2019 2019-08-20 53 21 1351 1368 journal article 10.1080/00222933.2019.1637475 75caa414-c102-4cf9-ade8-0f8b2d93b37b 1464-5262 3673676 Racekiela cresciscrystae sp. nov . Material examined Holotype . CNPGG ‒ 2331 La Capilla River ( Villa del Carbónı México Stateı México )ı 19° 43 ʹ 53.4´´ Nı 99°30´49.32´´ Wı 25.III.2017 . Paratypes . CNPGG‒2026 La Capilla River ( Villa del Carbónı México Stateı México )ı 19° 43 ʹ 55.1994 ʹ ’ Nı 99°30 ʹ 49.32 ʹ ’ W; 26 .III.2017. CNPGG‒2030 La Capilla River ( México Stateı México )ı 19°43 ʹ 57.72 ʹ ’ Nı 99°30 ʹ 50.3994 ʹ ’ W; 25 .III.2017. CNPGG‒2332 La Capilla River ( México State )ı 19°43 ʹ 53.4 ʹ ’ Nı 99°30´50.3994 ʹ ’ W; 25 .III.2017 . CNPGG‒2334 La Capilla River ( México State )ı 19°43´57.72´´ Nı 99°30 ʹ 51.12 ʹ ’ W; 26 .VI.2017 . CNPGG‒2335 La Capilla River ( México State )ı 19°44 ʹ 1.694 ʹ ’ Nı 99°30 ʹ 32.24 ʹ ’ W; 26 .VI.2017 . CNPGG‒2336 La Cañada ( Villa del Carbónı Estado de México )ı 19°46 ʹ 42.6 ʹ ’ Nı 99°28 ʹ 42.594 ʹ ’ W; 27 . VI.2017 . CNPGG‒2337 La Capilla River ( México State )ı 19°43 ʹ 58.08 ʹ ’ Nı 99°30 ʹ 48.944 ʹ ’ W; 26 .VI.2017 . Etymology Cresciscrystae is a compound name from the words crescis in Latin meaning rising and crista that means ridge; the main sponge surface trait. Ecology Racekiela cresciscrystae sp. nov. occurs in calmı and running watersı but always in shallow waters (less than 1 m depth) and encrusted on a solid substrate ( Figures 2 and 3 ). In calm waterı the species always grows as a thick encrusting sponge with bulbous outgrowths. Insteadı in running waterı the species has always been found as a thinner encrusting sponge. It is dark green colour in shadeı and lime-green exposed to light. Water quality conditions recorded for the different river sites are: Temperature 13.3 ‒ 14.7°Cı pH 6.7 ‒ 7.6ı dissolved oxygen 5.70 ‒ 8.3 mg /lı conductivity 0.054 ‒ 0.371 ms/cmı salinity 004 – 006 ppm. Figure 3. Racekiela cresciscrystae sp. nov. paratype localities at Villa del Carbón River. (a) and (b.) Sampling sites of the new species shown by arrows. (c) Encrusting live specimen, lime-green colour in underwater photography. (d) Lobate surface of paratype in live. General morphology The new species depicts two morphotypes; the more common is a thick encrusting form with raised ridges or bulbous outgrowths at the surface and dark green in colour when alive. It measures 36 cm long by 19.5 cm wideı 10 mm to up to 3.0 cm thick; the thickest parts owe to the bulbous outgrowthsı like conesı that measure 2.0 cm highı and 2.0 cm at the base ( Figure 2 ). The second morph is a flattened thinner encrustation measuring up to 3.0 mm thick with a lime-green colour ( Figure 3 ). The twoı are ochre yellow in dried stateı and light beige in alcohol. Compressible in consistency but fragileı smooth surface but microhispidı pierced by megascleres due to the skeletal arrangement. Several round oscula visible to the eyeı up to 7 mm in diameter. Ectosomal skeleton with tangential megascleres irregularly scatteredı besides upright oxeas with tips protruding the surface ( Figure 4 ). Choanosomal skeleton conforms an ill-defined isotropic network connected by ill-defined paucispicular tracts of oxeası and scattered megascleres in-between ( Figure 4 ). Also found in choanosome are some scattered birotules and pseudobirotules. Gemmules Exclusively spherical 500 ‒ 690 µm in diameter ( Figure 5 )ı pale yellow in colourı abundant at the basal portion and rare in the sponge body. It is an armed gemmule arranged by a gemmular tri-layered thecaı characterised by the outer gemmular layerı the pneumaticı and the inner layers. The thicker layer is the pneumatic oneı which has birotules radially embeddedı and pseudobirotulesı which generally protruding from the outer layer. Gemmules include an irregular number of chambers that concur with the inner layer. Inside a dense mass of thesocytes is observed. A single and simple foramen is present. Spicules Acanthoxeas always slightly spined all over and hastate ends 200 ‒ 252 ‒ 300 × 7.8 ‒ 10.9 ‒ 13 µmı few of them show centrotyloteı or very seldom malformations intersected fused like ( Figure 6 ). Many markedly thinly smooth and fusiform oxeas are also present;143 ‒ 206 ‒ 260 × 5.2 ‒ 6.2 ‒ 7.8 µm ( Figure 6 ); microscleres absent ( Table 1 ). Figure 4. Cross section throughout the sponge body in light micrographs. (a) Ectosomal tangential megascleres irregularly scattered, with upright oxeas protruding outside the surface. (b) Choanosomal skeletal network. Figure 5. SEM micrographs of gemmule from holotype CNPGG ‒ 2331 Racekiela cresciscrystae sp. nov. (a) Spherical gemmule with shattered foramen, and top view of rotules. (b) Detail of gemmule surface, with birotules (marked by arrows) and pseudobirotules. (c) Cross section of gemmule filled in with thesocytes and tri-layered theca. (d) Detail of tri-layered theca and foramen in a cross section gemmule (shattered at the upper side). (e) Detail of theca with irregular chambers (upper side of frame), thesocytes and pseudobirotulates going outside the surface (lower right side). (f) Detail of foramen taken from the shatter theca. Figure 6. SEM images of megascleres of holotype CNPGG ‒ 2331 Racekiela cresciscrystae sp. nov. (a) Spined oxea and detail of tips. (b) Oxeas not spined. (c) Acanthoxea malformation. (d) Spicular set for size comparison. Gemmuloscleres: birotules with length always greater than rotule diameterı 39 ‒ 51.2 ‒ 59 µm longı straight shaft usually smoothı 5.2 ‒ 5.5 ‒ 7.8 µm in diameterı very seldom bearing one or three acute spines; rotules are flatı some slightly umbonateı 20 ‒ 26 µm in diameter; they have deeply jagged edges with irregular acute raysı ornamented also with finely crenulate spines ( Figures 7 and 8 ). Proportion of the diameter of the rotule vs. length of the shaft is from 1.7 to 2.5. Figure 7. SEM images of gemmuloscleres of holotype CNPGG ‒ 2331 Racekiela cresciscrystae sp. nov. (a) Birotule with smooth shaft, one with very rare spiny shaft. (b) Different rotules showing flat to umbonate details. (c Various pseudobirotules shapes. (d) Pseudobirotules. II (e) Pseudobirotules tips. Figure 8. SEM images of spicules of paratype CNPGG-2027, (a) Spined oxea and detail of tips. (b) Different rotules (c) Rotule. (d) Various pseudobirotules shapes, (e) Rotule. (f), (g) Pseudobirotules II. Pseudobirotules with strongly or somewhat spined shaft. Spines can be straight or hookedı 57 ‒ 66.2 ‒ 75 × 5.2 ‒ 6.2 ‒ 10.4 µm . They are characterised by strongly hooked spines slightly umbonateı and sometimes with a prominent spike. Numerousı slightly smaller and thinner pseudobirotules with umbonate endingsı and with only small wartsı instead of spines ( Figures 7 and 8 ) ( Table 1 ).