Acanthodesmioidea Haeckel 1862

Superfamily ACANTHODESMIOIDEA Haeckel, 1862

Acanthodesmida Haeckel, 1862: 237, 265-266 [as both family and tribe]; 1882: 445 [as a tribe]; 1887: 970, 973 [as a subfamily of Coronida].

Spyridina Ehrenberg, 1846: 385 [nomen nudum, as a family];1847: 54 [as a family]; 1876: 156 [in Spumellaria].— Schomburgk 1847: 124, 126 [as a family]. — Petrushevskaya 1981: 327-328 [as a suborder].

Spyrida – Haeckel 1882: 440 [nomen nudum, as a family]. — Lankester 1885: 850 [as a family]. — Petrushevskaya 1971a: 240-243 [as a suborder]; 1971b: 990 [as a suborder]. — Petrushevskaya & Kozlova 1972: 529. — Riedel & Sanfilippo 1977: 868 [as a suborder]. — Anderson 1983: 39-40 [as a suborder]. — Sanfilippo et al. 1985: 661.

Spyroidea – Haeckel 1884: 31 [nomen nudum, as a family]; 1887: 895 1015-1021 [as a suborder]. — Bütschli 1889: 1979 [as an order]. — Haecker 1908: 445 [as a rank between suborder and family]. — Calkins 1909: 41 [as an order]. — Lankester et al. 1909: 147 [as an order]. — Schröder 1914: 90, 141-142 [as a suborder]. — Dacque 1933: 42 [rank unknown]. — Clark & Campbell 1942: 53 [as a suborder]; 1945: 29. — Campbell & Clark 1944a: 33 [as a suborder]; 1944b: 21. — Deflandre 1953: 430-431 [as a superfamily]. — Chediya 1959: 176 [as a superfamily]. — Anderson 1983: 29. — Cachon & Cachon 1985: 293 [as a superfamily]. — Chen & Tan 1996: 152 [as a suborder]. — Tan & Su 2003: 86 [as a suborder]. — Chen et al. 2017: 167 [as a suborder].

Stephoidea Haeckel, 1887: 895, 931-937 [as a suborder]. — Bütschli 1889: 1976 [as an order]. — nec Rüst 1892: 176 [as an order]. — Lankester et al. 1909: 147 [as an order]. — Popofsky 1913: 283 [s a suborder]. — Schröder 1914: 72, 87 [as a suborder]. — Dacque 1933: 42 [rank unknown]. — Clark & Campbell 1945: 29 [as a suborder]. — Deflandre 1953: 429-430 [as a superfamily]. — Chediya 1959: 167 [as a superfamily]. — Anderson 1983: 29. — Cachon & Cachon 1985: 291 [as a superfamily]. — Chen & Tan 1996: 152 [as a suborder]. — Tan & Su 2003: 83 [as a suborder]. — Chen et al. 2017: 165 [as a suborder].

Stephoidae – Delage & Hérouard 1896: 219 [as a suborder].

Spyroidae – Delage & Hérouard 1896: 233 [as a suborder].

Stephoida – Calkins 1909: 41 [as an order].

Spyroideen – Popofsky 1913: 304 [as a suborder].

Stephaniicae [sic] – Campbell 1954: D105-106 (= Stephanioidea) [as a superfamily].

Acanthodesmiacea [sic] – Loeblich & Tappan 1961: 227 (= Acanthodesmioidea) [as a superfamily]. — De Wever et al. 2001: 227 [as a superfamily].

Acanthodesmoidea [sic] – Petrushevskaya 1986: 136, 138 (= Acanthodesmioidea).

Spyridiniformes – Amon 2000: 25-26.

Spyridinata – Afanasieva et al. 2005: S304 [as an order]. — Afanasieva & Amon 2006: 153 [as an order].

DIAGNOSIS. — One sagittal ring (or D-shaped ring) including MB, A-rod, V-rod and AV-arch. D-, double L-, double l-rods tend to be well developed. The AV-arch is rarely absent. Many small appendages systematically extend from particular portions of these rods. Endoplasm of spherical shape with a thick capsular membrane, transparent in color. Gelatinous matter, if present, wraps the endoplasm, siliceous skeleton, and algal symbionts. Ectoplasm poorly recognized. Pseudopodia visible or invisible.

REMARKS

The Acanthodesmioidea consists of the Acanthodesmiidae, Cephalospyrididae, Paradictyidae and Stephaniidae. Molecular data obtained by Sandin et al. (2019) cannot be used when considering the morphological classification of the family within the Acanthodesmioidea. However, it amounts to the second highest environmental sequence, relative to Plagiacanthoidea, which have the highest (Sandin et al. 2019). Moreover, sequences of Acanthodesmioidea are particularly abundant in the subtropical and tropical South China Sea (Wu et al. 2014).

The appearance of the Acanthodesmioidea species may drastically vary. The images of the same specimen under different orientations were provided in several papers (Goll & BjØrklund 1980: pls 2, 3; 1985: figs 6-9; Tan & Su 1981: pls 1-3; Itaki 2009: pl. 13, figs 1-20). Based on absolute and relative Cartesian coordinates, a precise orientation is the first step to identify this group. The next steps should be followed: 1) Like in pylonioids (Zhang & Suzuki 2017: fig. 4), the absolute Cartesian coordinates (Type 1) are used to define the anatomical orientation of the specimen while the relative Cartesian coordinates (Type 2) are use to describe the orientation of a real specimen in the Type 2 coordinate system. Under Euclidean geometry, the way to define Types 1 and 2 of Acanthodesmioidea is mathematically identical to that of pylonioids by Zhang & Suzuki (2017). To do that, some modifications in previous studies of the Acanthodesmioidea were taken into account (Goll 1968: text-fig. 3B; Goll & BjØrklund 1985: fig. 5B); 2) the origin (O-point) under Euclidian geometry is defined as the joint point of Ax-rod with MB or the V-rod side end of MB for both coordinates of Types 1 and 2; 3) As for Type 1 coordinate, the sagittal plane (Sg-plane) is defined as to roughly include MB, A- and V-rod as well as the sagittal axis (Sg-axis) which is defined in order to include MB; 4) once O-point, Sg-plane and Sg-axis are defined, the polar axis (Pl-axis) is defined in a direction perpendicular to the Sg-axis on Sg-plane and the lateral axis (Lt-axis). The lateral axis is defined by an axis that is in a direction perpendicular to both the Sg- and Pl-axes. The lateral plane (Lt-plane) is defined by the plane including the Pl- and Lt-axes. Additionally, the equatorial (Eq-plane) plane is defined by the plane including the Lt- and Sg-axes; 5) Regarding, Type 2 coordinates, the short and longest axes of the shell are coded as the shortest axis (Sh-axis) and longest axis (Lo-axis). The remaining axis is placed on the remaining direction as middle axis (Md-axis). The longest side plane (Lo-plane) includes the Lo- and Sh-axes; the shortest side plane (Sh-plane) is defined by the Sh- and Md-axes, and the remaining plane as a middle one (Md-plane, including Md- and Lo-axes). The intersection angles among three axes, or three planes, are not necessary to be equal to 90° between each other although all of them must include the O-point. The coordinate system proposed by Goll (1968) and Goll & BjØrklund (1985) cannot be used due to an inappropriate mathematical definition with no O-point and mixture of Types 1 and 2 coordinate systems; 6) the orientation of a specimen faced to observers is defined by the A-rod being in front of the observers. Under the Type 1 coordinate system, the A-rod side direction along Sg-axis is specified as “dorsal” because of presence of D- (dorsal) rod and its opposite direc- tion as “ventral” because of presence of V- (ventral) rod. The right side along the Lt-axis is named “iustum” and left one “sinistram”. The direction of the Ax-rod or of the relevant structure is defined as “inferior” while the opposite side is defined as “supra”; and 7) in the Type 2 coordinate system, the front-back is oriented in the Sh-axis, the right and left in the Lo-axis and the apex-base in the Md-axis.

A second key aspect in understanding the structure of the Acanthodesmioidea, are many common skeletal frames and pores termed by Petrushevskaya (1969: fig. 1; 1971a: fig. 10): 1) Small appendages are systemically coded: c -spinule on the D-rod; t -spinule on the l-rod; p - and d -spinules on L-rod of the MB side; a -, m - and g -spinules on A-rod from the MB side; j -spinule on the V-rod; and f -, z - and q -spinules on the AV-arch of the V-side (Petrushevskaya 1969: fig. 1); 2) Large “pores” along a sagittal ring are named “sagittal pores.” A sagittal pore is always located on the Sg-plane under Type 1 coordinates; 3) Basal pores in the basal ring are coded as J -pores on the Dl-arch, Ca -pores on the Ll-arch and Cerv -pore found on the LV-arch (Petrushevskaya 1971a: fig. 10). These pores are aligned as J-, Ca - and Cerv -pores from the A- to V-rod sides (from the dorsal to the ventral sides).

The Acanthodesmioidea have been widely recognized (Goll 1968, 1969, 1972a, b, 1976, 1978, 1980; Goll & BjØrklund 1980, 1985), but there still remains many undescribed genera and species worldwide. In particular, few names have been proposed for early to early middle Miocene Acanthodesmioidea in, but not limited to, Japan and surrounding areas. To understand the taxonomy several identification criteria are required, such as: 1) the MB, Ax- and A-rods; 2) the orientation of the specimen under both Type 1 and Type 2 coordinates; 3) the number and name codes of the pores; 4) the anatomical position of rods and arches; and 5) the arch names around the sagittal ring. In spite of the difficulties in determining an assignable genus, the species are easily identified after a correct orientation of shell has been confirmed.

The number of basal pores ranges from three to six, but the anatomical architecture is different even when the same number of basal pores are observed. The numbers of the basal pores and their anatomical position is better defined by the presence of five types of pore pattern: 1) Six basal pores forming a full set of double J-, Ca - and Cerv -pores from the dorsal side (Goll 1968: pl. 174, fig. 10). In some taxa, six basal pores are visible from the ventral side, but the double J -basal pore is obliquely located on the dorsal side (Goll 1968: pl. 175, figs 15, 16; 1969: pl. 56, fig. 8; 1972a: pl. 47, fig. 2, pl. 58, fig. 3). If this tendency is extreme, the basal ring appears to have only four basal pores, with double Ca - and Cerv -pores (Goll 1972a: pl. 41, fig. 3); 2) Four basal double pores, the small pair is formed by a double Cerv -pore and the larger pair correspond to the double Ca- pore (Goll 1968: pl. 175, figs 7, 8; 1969: pl. 55, fig. 7, pl. 57, fig. 3;1972a: pl. 42, fig. 3, pl. 48, fig. 2, pl. 50, fig. 4); 3) Two basal pores, sometimes presented as a double pit-like pore originated from very large basal pores. These pores are related to the downward D-rod, and recognized as a double Cerv -pore and double Ca -pore (Goll 1972a: pl. 51, fig. 3). A double basal pore could also appear when the double Ca- and J - or Cerv -pores become degraded, resembling a double pit-like small pore near the base (Goll 1968: pl. 176, fig. 12), or when both J - and Cerv -pores are completely absent (Goll 1972a: pl. 37, figs 1-3). Another case is observed when the reduction of the double l-rod occurs and the pore is constructed with a -spinule of A-rod and a probable j- spinule of V-rod (Sugiyama 1998: pl. 6, figs 3b); 4) Three of three larger basal pores, the V- rod extends upwards from the basal ring and two Cerv -pores unite to become as a single pore (united Cerv -pore herein) and the remaining two pores pertain to the double Ca -pore (Goll 1972a: pl. 57, fig. 1); 5) Finally, the V-rod might be invisible, in this case, three basal pores and a double pit-like pore are found on the basal ring (Goll 1972a: pl. 62, fig. 3; Nishimura 1990: fig. 25.7), however, the double J- pore may be visible or invisible, appearing in this case a double pit (Goll 1969: pl. 56: fig. 8). Thus, double Ca -pores are generally the largest existing basal pores while double J -pores tend to disappear. However, little to nothing is known about the relationship between the taxonomic classification and the variability of basal pore patterns.